Charge Pump, 7-Channel
Smart LED Driver with I2C Interface
ADP8860
Rev. 0
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responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
07967-001
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700 www.analog.com
Fax: 781.461.3113 ©2009 Analog Devices, Inc. All rights reserved.
FEATURES
Charge pump with automatic gain selection of 1×, 1.5×, and
2× for maximum efficiency
Up to two built-in comparator inputs with programmable
modes for ambient light sensing
Outdoor, office, and dark modes for maximum backlight
power savings
7 independent and programmable LED drivers
6 drivers capable of 30 mA (typical)
1 driver capable of 60 mA (typical)
Programmable maximum current limit (128 levels)
Standby mode for <1 μA current consumption
16 programmable fade in and fade out times
0.1 sec to 5.5 sec
Choose from linear, square, or cubic rates
Fading override
I2C-compatible interface for all programming
Dedicated reset pin and built-in power-on reset (POR)
Short-circuit, overvoltage, and overtemperature protection
Internal soft start to limit inrush currents
Input-to-output isolation during faults or shutdown
Operation down to VIN = 2.5 V with undervoltage lockout
(UVLO) at VIN = 2.0 V
Small wafer level chip scale package (WLCSP) or lead frame
chip scale package (LFCSP)
APPLICATIONS
Mobile display backlighting
Mobile phone keypad backlighting
Dual RGB backlighting
LED indication
General backlighting of small format displays
GENERAL DESCRIPTION
The ADP8860 combines a programmable backlight LED charge
pump driver with automatic phototransistor control. This combi-
nation allows for significant power savings because it changes the
current intensity in office and dark ambient light conditions. By
performing this function automatically, it eliminates the need for
a processor to monitor the phototransistor.
The light intensity thresholds are fully programmable via the
I2C® interface. A second phototransistor input, with dedicated
comparators, improves the ambient light detection levels for
various user operating conditions.
TYPICAL OPERATING CIRCUIT
V
D3
D1
E3
D2
E4
D3
D4
D4
C4
D5
B4
D6/
CMP_IN2
B3
D7
ALS
V
OUT
OPTIONAL
PHOTOSENSOR
PHOTOSENSO
C3
CMP_IN
R
0.1µF
0.1µF
V
IN A3
1µF
E1
VDDIO
nRST
C2
VDDIO
SDA
E2
VDDIO
SCL
D2
VDDIO
nINT
A4
GND1
D1
GND2
B1
C2+
B2
C2–
C2
1µF
A1
C1+
C1
C1–
C1
1µF
V
OUT
A2
ADP8860
1µF
Figure 1.
The ADP8860 allows as many as six LEDs to be independently
driven up to 30 mA (typical). A seventh LED can be driven to
60 mA (typical). All LEDs are programmable for minimum/max-
imum current and fade in/out times via the I2C interface. These
LEDs can also be combined into groups to reduce the processor
instructions during fade in/out.
Driving this entire configuration is a two-capacitor charge pump
with gains of 1×, 1.5×, and 2×. This setup is capable of driving a
maximum IOUT of 240 mA from a supply of 2.5 V to 5.5 V. The
device includes a variety of safety features including short-circuit,
overvoltage, and overtemperature protection. These features
allow easy implementation of a safe and robust design. Addi-
tionally, input inrush currents are limited via an integrated soft
start combined with controlled input-to-output isolation.
The ADP8860 is available in two package types, either a compact
2 mm × 2.4 mm × 0.6 mm WLCSP (wafer level chip scale package)
or a small LFCSP (lead frame chip scale package).
ADP8860
Rev. 0 | Page 2 of 52
TABLE OF CONTENTS
Features .............................................................................................. 1
Applicat ions ....................................................................................... 1
General Description ......................................................................... 1
Typical Operating Circuit ................................................................ 1
Revision History ............................................................................... 2
Specifications ..................................................................................... 3
I2C Timing Diagram ..................................................................... 5
Absolute Maximum Ratings ............................................................ 6
Maximum Temperature Ranges ................................................. 6
Thermal Resistance ...................................................................... 6
ESD Caution .................................................................................. 6
Pin Configurations and Function Descriptions ........................... 7
Typical Performance Characteristics ............................................. 8
Theory of Operation ...................................................................... 12
Power Stage.................................................................................. 13
Operating Modes ........................................................................ 14
Backlight Operating Levels ....................................................... 16
Backlight Maximum and Dim Settings ................................... 17
Automated Fade In and Fade Out ............................................ 17
Backlight Turn On/Turn Off/Dim ........................................... 17
Automatic Dim and Turn Off Timers ..................................... 18
Fade Override ............................................................................. 19
Ambient Light Sensing .............................................................. 19
Automatic Backlight Adjustment ............................................. 20
Independent Sink Control ........................................................ 20
Short-Circuit Protection Mode ................................................ 21
Overvoltage Protection .............................................................. 21
Thermal Shutdown/Overtemperature Protection ................. 21
Inter rupts ..................................................................................... 23
Applications Information .............................................................. 24
Layout Guidelines....................................................................... 24
Example Circuits ........................................................................ 25
I2C Programming and Digital Control ........................................ 26
Backlight Register Descriptions ............................................... 30
Independent Sink Register Descriptions ................................. 37
Comparator Register Descriptions .......................................... 45
Outline Dimensions ....................................................................... 49
Ordering Guide .......................................................................... 50
REVISION HISTORY
5/09—Revision 0: Initial Version
ADP8860
Rev. 0 | Page 3 of 52
SPECIFICATIONS
VIN = 3.6 V, SCL = 2.7 V, SDA = 2.7 V, nINT = open, nRST = 2.7 V, CMP_IN = 0 V, VD1:D7 = 0.4 V, C1 = 1 F, C2 = 1 F, COUT = 1 F,
typical values are at TA = 25°C and are not guaranteed, minimum and maximum limits are guaranteed from TA = −40°C to +85°C, unless
otherwise noted.
Table 1.
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
SUPPLY
Input Voltage
Operating Range VIN 2.5 5.5 V
Startup Level VIN(START) V
IN increasing 2.05 2.30 V
Low Level VIN(STOP) V
IN decreasing 1.75 1.97 V
VIN(START) Hysteresis VIN(HYS) After startup 80 mV
UVLO Noise Filter tUVLO 10 μs
Quiescent Current IQ
Prior to VIN(START) I
Q(START) V
IN = VIN(START) − 100 mV 10 μA
During Standby IQ(STBY) V
IN = 3.6 V, Bit nSTBY = 0, SCL = SDA = 0 V 0.3 1.0 μA
After Startup and Switching IQ(ACTIVE) V
IN = 3.6 V, Bit nSTBY = 1, IOUT = 0 mA,
gain = 2×
4.5 7.2 mA
OSCILLATOR
Switching Frequency fSW 0.8 1 1.32 MHz
Duty Cycle D 50 %
OUPUT CURRENT CONTROL
Maximum Drive Current ID1:D7(MAX) V
D1:D7 = 0.4 V
D1 to D7 Bit SCR = 0 in the ISC7 register
TJ = 25°C 26.2 30 34.1 mA
TJ = −40°C to +85°C 24.4 34.1 mA
D7 Only (60 mA Setting) ID7(60 mA) V
D7 = 0.4 V, Bit SCR = 1 in the ISC7 register
TJ = 25°C 52.5 60 67 mA
TJ = −40°C to +85°C 48.8 67 mA
LED Current Source Matching1
IMATCH
All Current Sinks IMATCH7 V
D1:D7 = 0.4 V 2.0 %
D2 to D7 Current Sinks IMATCH6 V
D2:D7 = 0.4 V 1.5 %
Leakage Current on LED Pins ID1:D7(LKG) V
IN = 5.5 V, VD1:D7 = 2.5 V, Bit nSTBY = 1 0.5 μA
Equivalent Output Resistance ROUT
Gain = 1× VIN = 3.6 V, IOUT = 100 mA 0.5 Ω
Gain = 1.5× VIN = 3.1 V, IOUT = 100 mA 3.0 Ω
Gain = 2× VIN = 2.5 V, IOUT = 100 mA 3.8 Ω
Regulated Output Voltage VOUT(REG) V
IN = 3 V, gain = 2×, IOUT = 10 mA 4.3 4.9 5.5 V
AUTOMATIC GAIN SELECTION
Minimum Voltage
Gain Increases VHR(UP) Decrease VD1:D7 until the gain switches up 162 200 276 mV
Minimum Current Sink Headroom
Voltage
VHR(MIN) I
DX = IDX(MAX) × 95% 180 mV
Gain Delay tGAIN The delay after gain has changed and
before gain is allowed to change again
100 μs
ADP8860
Rev. 0 | Page 4 of 52
Parameter Symbol Test Conditions/Comments Min Typ Max Unit
AMBIENT LIGHT SENSING
COMPARATORS
Ambient Light Sensor Current IALS CMP_IN = VD6 = 2.8 V, Bit CMP2_SEL = 1 0.70 1.08 1.33 mA
DAC Bit Step
Threshold L2 Level IL2BIT I
L2BIT = IALS/250 4.3 μA
Threshold L3 Level IL3BIT I
L3BIT = IALS/2000 0.54 μA
FAULT PROTECTION
Startup Charging Current Source ISS V
IN = 3.6 V, VOUT = 0.8 × VIN 2.5 3.75 5.5 mA
Output Voltage Threshold VOUT
Exit Soft Start VOUT(START) V
OUT rising 0.92 × VIN V
Short-Circuit Protection VOUT(SC) V
OUT falling 0.55 × VIN V
Output Overvoltage Protection VOVP
Activation Level 5.8 V
OVP Recovery Hysteresis 500 mV
Thermal Shutdown
Threshold TSD 150 °C
Hysteresis TSD(HYS) 20 °C
Isolation from Input to Output
During Fault
IOUTLKG V
IN = 5.5 V, VOUT = 0 V, Bit nSTBY = 0 1.5 μA
Time to Validate a Fault tFAULT 2 μs
I2C INTERFACE
VDDIO Voltage Operating Range VDDIO 5.5 V
Logic Low Input2 VIL V
IN = 3.6 V 0.6 V
Logic High Input3 VIH V
IN = 3.6 V 1.30 V
I2C TIMING SPECIFICATIONS Guaranteed by design
Delay from Reset Deassertion to
I2C access
tRESET 20 μs
SCL Clock Frequency fSCL 400 KHz
SCL High Time tHIGH 0.6 μs
SCL Low Time tLOW 1.3 μs
Setup Time
Data tSU, DAT 100 ns
Repeated Start tSU, STA 0.6 μs
Stop Condition tSU, STO 0.6 μs
Hold Time
Data tHD, DAT 0 0.9 μs
Start/Repeated Start tHD, STA 0.6 μs
Bus Free Time (Stop and Start
Conditions)
tBUF 1.3 μs
Rise Time (SCL and SDA) tR 20 + 0.1 CB 300 ns
Fall Time (SCL and SDA) tF 20 + 0.1 CB 300 ns
Pulse Width of Suppressed Spike tSP 0 50 ns
Capacitive Load Per Bus Line CB 400 pF
1 Current source matching is calculated by dividing the difference between the maximum and minimum current from the sum of the maximum and minimum.
2 VIL is a function of the input voltage. See in the section for typical values over operating ranges. Figure 16
Figure 16
Typical Performance Characteristics
Typical Performance Characteristics
3 VIH is a function of the input voltage. See in the section for typical values over operating ranges.
ADP8860
Rev. 0 | Page 5 of 52
I2C TIMING DIAGRAM
S
D
A
SCL
S
S = START CONDITION
Sr = REPEATED START CONDITION
P = STOP CONDITION
Sr P S
t
LOW
t
R
t
HD, DAT
t
HIGH
t
SU, DAT
t
F
t
F
t
SU, STA
t
HD, STA
t
SP
t
SU, STO
t
BUF
t
R
07967-002
Figure 2. I2C Interface Timing Diagram
ADP8860
Rev. 0 | Page 6 of 52
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 2.
Parameter Rating
VIN, VOUT −0.3 V to +6 V
D1, D2, D3, D4, D5, D6, and D7 −0.3 V to +6 V
CMP_IN −0.3 V to +6 V
nINT, nRST, SCL, and SDA −0.3 V to +6 V
Output Short-Circuit Duration Indefinite
Operating Ambient Temperature Range –40°C to +85°C1
Operating Junction Temperature Range –40°C to +125°C
Storage Temperature Range –65°C to +150°C
Soldering Conditions JEDEC J-STD-020
ESD (Electrostatic Discharge)
Human Body Model (HBM) ±2 kV
Charged Device Model (CDM) ±2 kV
θJA (junction to air) is specified for the worst-case conditions,
that is, a device soldered in a circuit board for surface-mount
packages. The θJA, θJB (junction to board), and θJC (junction to
case) are determined according to JESD51-9 on a 4-layer
printed circuit board (PCB) with natural convection cooling.
For the LFCSP package, the exposed pad must be soldered to
the GND1 and/or GND2 terminal(s) on the board.
Table 3. Thermal Resistance1
Package Type θJA θ
JB θ
JC Unit
WLCSP 48 9 N/A °C/W
LFCSP_VQ 49.5 N/A 5.3 °C/W
1 N/A means not applicable.
1 The maximum operating junction temperature (TJ(MAX)) supersedes the
maximum operating ambient temperature (TA(MAX)). See the Maximum
Temperature Ranges section for more information. ESD CAUTION
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
Absolute maximum ratings apply individually only, not in
combination. Unless otherwise specified, all voltages are
referenced to GND.
MAXIMUM TEMPERATURE RANGES
The maximum operating junction temperature (TJ(MAX))
supersedes the maximum operating ambient temperature
(TA(MAX)). Therefore, in situations where the ADP8860 is
exposed to poor thermal resistance and a high power
dissipation (PD), the maximum ambient temperature may need
to be derated. In these cases, the ambient temperature
maximum can be calculated with the following equation:
TA(MAX) = TJ(MAX) − (θJA × PD(MAX))
ADP8860
Rev. 0 | Page 7 of 52
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
PIN 1
INDICATOR
1D3
2D2
3D1
4SCL
5nRST
13 VOUT
14 VIN
15 GND1
12 C2+
11 C1+
6
nINT
7
SDA
8
GND2
10
C2–
9
C1–
18 CMP_IN
19 D5
20 D4
17 D6/CMP_IN2
16 D7
TOP VIEW
(Not to Scale)
ADP8860
NOTES
1. CONNECT THE EXPOSED PADDLE
TO GND1 AND/OR GND2.
0
7967-003
07967-004
TOP VIEW
(BALL SIDE DOWN)
Not to Scale
ADP8860
1
A
B
C
D
234
Figure 3. LFCSP Pin Configuration
C1+
C1–
C2+
GND2
nRST
VIN
D7
CMP_IN
D1
D2
GND1VOUT
D5
D6/
CMP_IN2
SDA
C2–
nINT D4
D3SCL
E
Figure 4. WLCSP Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
Mnemonic Description LFCSP WLCSP
14 A3 VIN Input Voltage 2.5 V to 5.5 V.
3 D3 D1 LED Sink 1.
2 E3 D2 LED Sink 2.
1 E4 D3 LED Sink 3.
20 D4 D4 LED Sink 4.
19 C4 D5 LED Sink 5.
17 B4 D6/CMP_IN2 LED Sink 6/Comparator Input for Second Phototransistor. When using this pin as a second
phototransistor input, a capacitor (0.1 μF recommended) must be connected from this pin to ground.
16 B3 D7 LED Sink 7.
18 C3 CMP_IN Comparator Input for Phototransistor. When using this function, a capacitor (0.1 μF recommended) must
be connected from this pin to ground.
13 A2 VOUT Charge Pump Output.
11 A1 C1+ Charge Pump C1+.
9 C1 C1− Charge Pump C1−.
12 B1 C2+ Charge Pump C2+.
10 B2 C2− Charge Pump C2−.
15 A4 GND1 Ground. Connect the exposed pad to GND1 and/or GND2.
8 D1 GND2 Ground. Connect the exposed pad to GND1 and/or GND2.
6 D2 nINT Processor Interrupt (Active Low). Requires an external pull-up resistor. If this pin is not used, it can be left
floating.
5 E1 nRST Hardware Reset (Active Low). This bit resets the device to the default conditions. If not used, this pin
must be tied above VIH(MIN).
7 C2 SDA I2C Serial Data. Requires an external pull-up resistor.
4 E2 SCL I2C Clock. Requires an external pull-up resistor.
ADP8860
Rev. 0 | Page 8 of 52
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 3.6 V, SCL = 2.7 V, SDA = 2.7 V, nRST = 2.7 V, VD1:D7 = 0.4 V, CIN = 1 μF, C1 = 1 μF, C2 = 1 μF, COUT = 1 μF, TA= 25°C, unless
otherwise noted.
2.0
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
I
Q
(mA)
V
IN
(V)
+25°C
+85°C
+105°C
–40°C
I
OUT
= NO L OAD
07967-100
Figure 5. Typical Operating Current, G = 1×
5.0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
I
Q
(mA)
V
IN
(V)
+25°C
+85°C
+105°C
–40°C
I
OUT
= NO L OAD
07967-101
Figure 6. Typical Operating Current, G = 2×, IQ(ACTIVE)
10
1
0.1
0.01
0.001 10 23456
IQ (µA)
VIN (V)
+25°C
+85°C
+105°C
–40°C
SCL = SDA = 0V
nRS T = 2. 7V
07967-102
Figure 7. Typical Standby IQ
35
30
25
20
15
10
5
00 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
I
OUT
(mA)
V
HR
(V)
V
IN
= 3. 6V
I
D1:D7
= 30mA
D1
D2
D3
D4
D5
D6
D7
07967-103
Figure 8. Typical Diode Current vs. Current Sink Headroom Voltage (VHR)
35
34
33
32
31
30
29
28
27
26
252.0 5.52.5 3.0 3.5 4.0 4.5 5.0
I
OUT
(mA)
V
IN
(V)
V
D1:D7
= 0.4V
D1
D2
D3
D4
D5
D6
D7
07967-104
Figure 9. Typical Diode Matching vs. VIN
6
0
1
2
3
4
5
0.2 2.01.81.61.41.21.00.80.60.4
MI SMATCH (%)
VHR (V)
+25°C
+85°C
+105°C
–40°C VIN = 3. 6V
ID1:D7 = 30mA
07967-105
Figure 10. Typical Diode Matching vs. Current Sink Headroom Voltage (VHR)
ADP8860
Rev. 0 | Page 9 of 52
35
5
10
15
20
25
30
V
IN
= 3.6V
I
D1:D7
= 30mA
0
I
OUT
(mA)
00.2 2.01.81.61.41.21.00.80.60.4
V
HR
(V)
–40°C
+25°C
+85°C
+105°C
07967-106
Figure 11. Typical Diode Current vs. Current Sink Headroom Voltage (VHR)
1
–5
–4
–3
–2
–1
0
V
IN
= 3.6V
V
D1:D7
= 0.40V
–6
I
OUT
DEVIATION (%)
–40 –10 20 50 80 110
JUNCTION TEMPERATURE (°C)
07967-107
Figure 12. Typical Change In Diode Current vs. Temperature
7
6
5
4
3
2
1
R
OUT
(Ω)
0
–40 –20 0 20 40 60 80 100
TEMPERATURE (°C)
I
OUT
= 100mA
G = 1× @ V = 3.6V
G = 1.5× @ V
IN
= 3V
G = 2× @ V
IN
= 2.5V
IN
07967-108
Figure 13. ROUT vs. Temperature
1.0
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
R
OUT
(Ω)
V
IN
(V)
+25°C
+85°C
+105°C
–40°C
I
OUT
= 100mA
07967-109
Figure 14. Typical ROUT (G = 1×) vs. VIN
10
9
8
7
6
5
4
3
2
1
0
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
I
OUT
(mA)
V
IN
(V)
+25°C
+85°C
+105°C
–40°C
V
OUT
= 80% OF V
IN
07967-110
Figure 15. Typical Soft Start Current, ISS
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
2.5 3.0 3.5 4.0 4.5 5.0 5.5
THRESHOLD (V)
V
IN
(V)
V
IL
= +25°C
V
IL
= +85°C
V
IL
= –40°C
V
IH
= +25°C
V
IH
= +85°C
V
IH
= –40°C
07967-111
Figure 16. Typical I2C Thresholds, VIH and VIL
ADP8860
Rev. 0 | Page 10 of 52
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
I
ALS
(mA)
3.02.5 3.5 4.0 4.5 5.0 5.5
V
IN
(V)
–40°C
+25°C
+85°C
+105°C
07967-112
Figure 17. Typical ALS Current, IALS
5.5
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
V
IN
= 3V
GAIN = 2×
I
OUT
= 10mA
4.5
4.6
V
OUT
(V)
–10–40 20 50 80 110
JUNCTION TEMPERATURE (°C)
07967-113
Figure 18. Typical Regulated Output Voltage (VOUT(REG))
6.0
5.8
5.6
5.4
V
OUT
(V)
5.2
–10–40 20 50 80 110
JUNCTION TEMPERATURE (°C)
OVP THRESHOLD
OVP RECOVERY
07967-114
Figure 19. Typical Overvoltage Protection (OVP) Threshold
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
450
400
350
300
250
200
150
100
50
0
2.5 5.55.04.54.03.53.0
EFFICIENCY (%)
I
IN
(mA)
V
IN
(V)
I
OUT
= 140mA, Vf = 3.1V
I
OUT
= 210mA, Vf = 3.2V
07967-115
Figure 20. Typical Efficiency (Low Vf Diode)
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
450
400
350
300
250
200
150
100
50
0
2.5 5.55.04.54.03.53.0
EFFICIENCY (%)
I
IN
(mA)
V
IN
(V)
I
OUT
= 140mA, Vf = 3.85V
I
OUT
= 210mA, Vf = 4.25V
07967-116
Figure 21. Typical Efficiency (High Vf Diode)
1
3
T
500ns/DIV
V
IN
(AC-COUPLED) 50mV/DIV
V
OUT
(AC-COUPLED) 50mV/DIV
I
IN
(AC-COUPLED) 10mA/DIV
C
IN
= 1µF, C
OUT
= 1µF, C1 = 1µF, C2 = 1µF
V
IN
= 3.6V
I
OUT
= 120mA
07967-117
2
Figure 22. Typical Operating Waveforms, G = 1×
ADP8860
Rev. 0 | Page 11 of 52
T
V
IN
(AC-COUPLED) 50mV/DIV
1
V
OUT
(AC-COUPLED) 50mV/DIV
2
I
IN
(AC-COUPLED) 10mA/DIV
3
500ns/DIV
C
IN
= 1µF, C
OUT
= 1µF, C1 = 1µF, C2 = 1µF
V
IN
= 3.0V
I
OUT
= 120mA
07967-118
Figure 23. Typical Operating Waveforms, G = 1.5×
T
V
IN
(AC-COUPLED) 50mV/DIV
1
V
OUT
(AC-COUPLED) 50mV/DIV
2
I
IN
(AC-COUPLED) 10mA/DIV
3
C
IN
= 1µF, C
OUT
= 1µF, C1 = 1µF, C2 = 1µF
V
IN
= 2.5V
I
OUT
= 120mA 500ns/DIV
07967-119
Figure 24. Typical Operating Waveforms, G = 2×
2
4
100µs/DIV
I
OUT
(10mA/DIV)
V
OUT
(1V/DIV)
I
IN
(10mA/DIV)
V
IN
= 3.7V
07967-120
Figure 25. Typical Start-Up Waveform
ADP8860
Rev. 0 | Page 12 of 52
THEORY OF OPERATION
The ADP8860 combines a programmable backlight LED charge
pump driver with automatic phototransistor control. This combi-
nation allows for significant power savings because it is able to
change the current intensity based on the lighting conditions. It
performs this function automatically thereby removing the
need for a processor to monitor the phototransistor. The light
intensity levels are fully programmable via the I2C interface. A
second phototransistor input, with dedicated comparators,
improves the ambient light detection abilities for various user-
operating conditions.
The ADP8860 allows up to seven LEDs to be independently
driven up to 30 mA (typical). The seventh LED can also be
driven to 60 mA (typical). All LEDs can be individually pro-
grammed or combined into a group to operate backlight LEDs.
A full set of safety features including short-circuit, overvoltage,
and overtemperature protection with input-to-output isolation
allow for a robust and safe design. The integrated soft start
limits inrush currents at startup, restart attempts, and gain
transitions.
C1
1µF
C2
1µF
GND2
D1
nINT
CMP_IN
C3
D2
C
OUT
VOUT
A2
C
IN
VIN V
REFS
I
REFS
STNDBY EN
VIN
VBAT
C1+
SDA
C2
SCL
E2
I
2
C
LOGIC
VDDIO
STNDBY
SWITCH CONTROL
ILED CONTROL
A1
C1
B1
B2
C1–
C2+
C2–
nRST
E1
NOISE FILTER
50µs
RESET
A3
D2
E3
D3
E4
D4
D4
D5
C4
D6
B4
D7
B3
D1
D3
V
ALS
OPTIONAL
PHOTOSENSOR
ID1 ID2 ID3 ID4 ID5 ID6 ID7
GAIN
SELECT
LOGIC
CHARGE
PUMP
LOGIC
V
IN
LIGHT
SENSOR
LOGIC
GND1
A4
CLK
UVLO
PHOTOSENSOR
CONVERSION
CHARGE
PUMP
(1×, 1.5×, 2×)
SOFT START
07967-011
I
SS
Figure 26. Detailed Block Diagram
ADP8860
Rev. 0 | Page 13 of 52
POWER STAGE
Because typical white LEDs require up to 4 V to drive them,
some form of boosting is required over the typical variation in
battery voltage. The ADP8860 accomplishes this with a high
efficiency charge pump capable of producing a maximum IOUT
of 240 mA over the entire input voltage range (2.5 V to 5.5 V).
Charge pumps use the basic principle that a capacitor stores
charge based on the voltage applied to it, as shown in the
following equation:
Q = C × V (1)
By charging the capacitors in different configurations, the
charge, and therefore the gain, can be optimized to deliver
the voltage required to power the LEDs. Because a fixed
charging and discharging combination must be used, only
certain multiples of gain are available. The ADP8860 is capable
of automatically optimizing the gain (G) from 1×, 1.5×, and 2×.
These gains are accomplished with two capacitors (labeled C1
and C2 in Figure 26) and an internal switching network.
In G = 1× mode, the switches are configured to pass VIN
directly to VOUT. In this mode, several switches are connected
in parallel to minimize the resistive drop from input to output.
In G = 1.5× and 2× modes, the switches alternatively charge
from the battery and discharge into the output. For G = 1.5×,
the capacitors are charged from VIN in series and are discharged
to VOUT in parallel. For G = 2×, the capacitors are charged
from VIN in parallel and are discharged to VOUT in parallel. In
certain fault modes, the switches are opened and the output is
physically isolated from the input.
Automatic Gain Selection
Each LED that is driven requires a current source. The voltage
on this current source must be greater than a minimum head-
room voltage (200 mV typical) to maintain accurate current
regulation. The gain is automatically selected based on the
minimum voltage (VDx) at all of the current sources. At startup,
the device is placed into G = 1× mode and the output charges
to VIN. If any VDx level is less than the required headroom
(200 mV), the gain is increased to the next step (G = 1.5×).
A 100 s delay is allowed for the output to stabilize prior to
the next gain switching decision. If there remains insufficient
current sink headroom, then the gain is increased again to 2×.
Conversely, to optimize efficiency, it is not desirable for the
output voltage to be too high. Therefore, the gain reduces when
the headroom voltage is great enough. This point (labeled
VDMAX in Figure 27) is internally calculated to ensure that the
lower gain still results in ample headroom for all the current
sinks. The entire cycle is illustrated in Figure 27.
Note that the gain selection criteria apply only to active current
sources. If current sources have been deactivated through an
I2C command (for example, only five LEDs are used), then the
voltages on the deactivated current sources are ignored.
ADP8860
Rev. 0 | Page 14 of 52
07967-012
NOTES
1.
V
DMAX
IS THE CALCULATED GAIN DOWN TRANSITION POINT.
WAIT
100µs (TYP) MIN (V
D1:D7
) < V
HR(UP)
0
0
1
1
1
1
0
0
STATUP:
CHARGE
V
IN
TO V
OUT
EXIT STBY
VOUT > V
OUT(START)
1
WAIT
100µs (TYP)
WAIT
100µs (TYP)
MIN (V
D1:D7
) < V
HR(UP)
MIN (V
D1:D7
) > V
DMAX
MIN (V
D1:D7
) < V
DMAX
G = 2
G = 3/2
EXIT
STARTUP
G = 1
STBY
0
Figure 27. State Diagram for Automatic Gain Selection
Soft Start Feature
At startup (either from UVLO activation or fault/standby
recovery), the output is first charged by ISS (3.75 mA typical)
until it reaches about 92% of VIN. This soft start feature reduces
the inrush current that is otherwise present when the output
capacitance is initially charged to VIN. When this point is
reached, the controller enters 1× mode. If the output voltage is
not sufficient, then the automatic gain selection determines the
optimal point as defined in the Automatic Gain Selection section.
OPERATING MODES
There are four different operating modes: active, standby,
shutdown, and reset.
Active Mode
In active mode, all circuits are powered up and in a fully
operational state. This mode is entered when nSTBY (in
Register MDCR) is set to 1.
Standby Mode
Standby mode disables all circuitry except for the I2C receivers.
Current consumption is reduced to less than 1 A. This mode is
entered when nSTBY is set to 0 or when the nRST pin is held
low for more than 100 s (maximum). When standby is exited,
a soft start sequence is performed.
Shutdown Mode
Shutdown mode disables all circuitry, including the I2C receivers.
Shutdown occurs when VIN is below the undervoltage thresholds.
When VIN rises above VIN(START) (2.05 V typical), all registers are
reset and the part is placed into standby mode.
Reset Mode
In reset mode, all registers are set to their default values and the
part is placed into standby. There are two ways to reset the part:
power-on reset (POR) and the nRST pin. POR is activated any-
time that the part exits shutdown mode. After a POR sequence
is complete, the part automatically enters standby mode.
After startup, the part can be reset by pulling the nRST pin low.
As long as the nRST pin is low, the part is held in a standby state
but no I2C commands are acknowledged (all registers are kept
at their default values). After releasing the nRST pin, all registers
remain at their default values, and the part remains in standby;
however, the part does accept I2C commands.
The nRST pin has a 50 s (typical) noise filter to prevent inad-
vertent activation of the reset function. The nRST pin must be
held low for this entire time to activate reset.
The operating modes function according to the timing diagram
in Figure 28.
ADP8860
Rev. 0 | Page 15 of 52
V
IN
nSTBY
nRST
V
OUT
V
IN
SHUTDOWN
V
IN
CROSSES ~2.05V AND TRIGGERS POWER ON RESET
BIT nSTBY IN REGISTER
MDCR GOES HIGH
nRST MUST BE HIGH FOR 20µs (MAX)
BEFORE SENDING I
2
C COMMANDS
nRST IS LOW, WHICH FORCES nSTBY LOW
AND RESETS ALL I
2
C REGISTERS
GAIN CHANGES ONLY OCCUR WHEN NECESSARY,
~100µs DELAY BETWEEN POWER UP AND
WHEN I
2
C COMMANDS CAN BE RECEIVED
~3.75mA CHARGES
V
OUT
TO V
IN
LEVEL
25µs TO 100µs NOISE FILTER
BUT HAVE A MIN TIME BEFORE CHANGING
1×
1.5×
2×
SOFT STARTSOFT START 10µs 100µs
0
7967-013
Figure 28. Typical Timing Diagram
ADP8860
Rev. 0 | Page 16 of 52
BACKLIGHT OPERATING LEVELS
Backlight brightness control operates in three distinct levels:
daylight (L1), office (L2), and dark (L3). The BLV bits in
Register 0x04 control the specific level in which the backlight
operates. These bits can be changed manually, or if in automatic
mode (CMP_AUTOEN is set high in Register 0x01), by the
ambient light sensor (see the Ambient Light Sensing section).
By default, the backlight operates at daylight level (BLV = 00),
where the maximum brightness is set using Register 0x09
(BLMX1). A daylight dim setting can also be set using
Register 0x0A (BLDM1). When operating at office level (BLV =
01), the backlight maximum and dim brightness settings are set
by Register 0x0B (BLMX2) and Register 0x0C (BLDM2). When
operating at the dark level (BLV = 10), the backlight maximum
and dim brightness settings are set by Register 0x0D (BLMX3)
and Register 0x0E (BLDM3).
D
A
YLIGHT (L1) OFFICE (L2) DARK (L3)
HT CURRENT
DAYLIGHT_MAX
OFFICE_MAX
BACKLIGHT OPERATING LEVELS
BACKLIG
DAYLIGHT_DIM
DARK_MAX
DARK_DIM
OFFICE_DIM
0
07967-014
30mA
Figure 29. Backlight Operating Levels
ADP8860
Rev. 0 | Page 17 of 52
BACKLIGHT MAXIMUM AND DIM SETTINGS
The backlight maximum and dim current settings are deter-
mined by a 7-bit code programmed by the user into the
registers previously listed in the Backlight Operating Levels
section. The 7-bit resolution allows the user to set the backlight
to one of 128 different levels between 0 mA and 30 mA. The
ADP8860 can implement two distinct algorithms to achieve a
linear and a nonlinear relationship between input code and
backlight current. The law bits in Register 0x04 are used to
change between these algorithms.
By default, the ADP8860 uses a linear algorithm (law = 00),
where the backlight current increases linearly for a
corresponding increase of input code. Backlight current (in
millamperes) is determined by the following equation:
Backlight Current (mA) = Code × (Full-Scale Current/127) (2)
where:
Code is the input code programmed by the user.
Full-Scale Current is the maximum sink current allowed per
LED (typically 30 mA).
The ADP8860 can also implement a nonlinear (square approxima-
tion) relationship between input code and backlight current
level. In this case (law = 01), the backlight current (in
milliamperes) is determined by the following equation:
2
127
)mA( ⎟
⎟
⎞
⎜
⎜
⎛−
×= CurrentScaleFull
CodeCurrentBacklight
⎠⎝
(3)
Figure 30 shows the backlight current level vs. input code for
both the linear and square law algorithms.
30
25
20
15
10
5
BACKLIGHT CURRENT (mA)
0
0 32 64 96 128
SINK CODE
LINEAR
SQUARE
07967-015
Figure 30. Backlight Current vs. Input Code
AUTOMATED FADE IN AND FADE OUT
The LED drivers are easily configured for automated fade in
and fade out. Sixteen fade in and fade out rates can be selected
via the I2C interface. Fade in and fade out rates range from
0.1 sec to 5.5 sec (per full-scale current, either 30 mA or 60 mA).
Table 5. Available Fade In and Fade Out Rates
Code Fade Rate (in sec per Full-Scale Current)
0000 0.1 (disabled)
0001 0.3
0010 0.6
0011 0.9
0100 1.2
0101 1.5
0110 1.8
0111 2.1
1000 2.4
1001 2.7
1010 3.0
1011 3.5
1100 4.0
1101 4.5
1110 5.0
1111 5.5
The fade profile is based on the transfer law selected (linear,
square, Cubic 10, or Cubic 11) and the delta between the actual
current and the target current. Smaller changes in current
reduce the fade time. For linear and square law fades, the fade
time is given by
Fade Time = Fade Rate × (Code/127) (4)
where the Fade Rate is shown in Table 5 .
The Cubic 10 and Cubic 11 laws also use the square backlight
currents in Equation 3; however, the time between each step is
varied to produce a steeper slope at higher currents and a
shallower slope at lighter currents (see Figure 31).
30
0
5
10
15
20
25
010.750.500.25
CURRENT (mA)
UNIT FADE TIME
.00
LINEAR
SQUARE
CUBIC 11
CUBIC 10
07967-016
Figure 31. Comparison of the Dimming Transfers Laws
BACKLIGHT TURN ON/TURN OFF/DIM
With the device in active mode (nSTBY = 1), the backlight can
be turned on using the BL_EN bit in Register 0x01. Before
turning on the backlight, the user chooses which level (daylight
(L1), office (L2), or dark (L3)) in which to operate, and ensures
that maximum and dim settings are programmed for that level.
ADP8860
Rev. 0 | Page 18 of 52
The backlight turns on when BL_EN = 1. The backlight turns
off when BL_EN = 0.
MAX
BACKLIGHT
CURRENT
BL_EN = 1 BL_EN = 0
0
7967-017
Figure 32. Backlight Turn On/Off
While the backlight is on (BL_EN = 1), the user can change to
the dim setting by programming DIM_EN = 1 in Register 0x01.
If DIM_EN = 0, the backlight reverts to its maximum setting.
MAX
DIM
BACKLIGHT
CURRENT
BL_EN = 1 DIM_EN = 1 DIM_EN = 0 BL_EN = 0
0
7967-018
Figure 33. Backlight Turn On/Dim/Turn Off
The maximum and dim settings can be set between 0 mA and
30 mA; therefore, it is possible to program a dim setting that is
greater than a maximum setting. For normal expected opera-
tion, ensure that the dim setting is programmed to be less than
the maximum setting.
AUTOMATIC DIM AND TURN OFF TIMERS
The user can program the backlight to dim automatically by
using the DIMT timer in Register 0x07. The dim timer has 127
settings ranging from 1 sec to 127 sec. Program the dim timer
(DIMT) before turning on the backlight. If BL_EN = 1, the
backlight turns on to its maximum setting and the dim timer
starts counting. When the dim timer expires, the internal state
machine sets DIM_EN = 1, and the backlight enters its dim
setting.
MAX
DIM
BL_EN = 1 BL_EN = 0DIM_EN = 1 DIM_EN = 0 DIM_EN = 1
BACKLIGHT
CURRENT DIM TIMER
RUNNING
DIM TIMER
RUNNING
SET BY USER
SET BY INTERNAL STATEMACHINE
0
7967-019
Figure 34. Dim Timer
If the user clears the DIM_EN bit, the backlight reverts to its
maximum setting and the dim timer begins counting again.
When the dim timer expires, the internal state machine again
sets DIM_EN = 1, and the backlight enters its dim setting. The
backlight can be turned off at any point during the dim timer
countdown by clearing BL_EN.
The user can also program the backlight to turn off automati-
cally by using the OFFT timer in Register 0x06. The off timer
has 127 settings ranging from 1 sec to 127 sec. Program the off
timer (OFFT) before turning on the backlight. If BL_EN = 1,
the backlight turns on to its maximum setting and the off timer
starts counting. When the off timer expires, the internal state
machine clears the BL_EN bit, and the backlight turns off.
MAX
BL_EN = 1 BL_EN = 0
BACKLIGHT
CURRENT OFF TIMER
RUNNING
SET BY USER
SET BY INTERNAL STATE MACHINE
07967-020
Figure 35. Off Timer
The backlight can be turned off at any point during the off
timer countdown by clearing BL_EN.
The dim timer and off timer can be used together for sequential
maximum-to-dim-to-off functionality. With both the dim and
off timers programmed, if BL_EN is asserted, the backlight
turns on to its maximum setting, and when the dim timer
expires, the backlight changes to its dim setting. When the off
timer expires, the backlight turns off.
ADP8860
Rev. 0 | Page 19 of 52
MAX
DIM
BACKLIGHT
CURRENT
BL_EN = 1 BL_EN = 0DIM_EN = 1
DIM TIMER
RUNNING
OFF TIMER
RUNNING
SET BY USER
SET BY INTERNAL STATE MACHINE
07967-021
Figure 36. Dim and Off Timers Used Together
FADE OVERRIDE
A fade override feature (FOVR in Register CFGR (0x04)) enables
the host to override the preprogrammed fade in or fade out
settings. If FOVR is set and the backlight is enabled in the
middle of a fade out process, the backlight instantly (within
approximately 100 ms) returns to its maximum setting. Alter-
natively, if the backlight is fading in, reasserting BL_EN overrides
the programmed fade in time and the backlight instantly goes
to its final fade value. This is useful for situations where a key
is pressed during a fade sequence. However, if FOVR is cleared
and the backlight is enabled in the middle of a fade process, the
backlight gradually brightens from where it was interrupted (it
does not go down to 0 and then come back on).
MAX
BACKLIGHT
CURRENT FADE-IN
OVER-RIDDEN
FADE-OUT
OVER-RIDDEN
BL_EN = 1 BL_EN = 0 BL_EN = 1 BL_EN = 0BL_EN = 1
(RE-ASSERTED)
07967-022
Figure 37. Fade Override Function (FOVR is High)
AMBIENT LIGHT SENSING
The ADP8860 integrates two ambient light sensing comparators.
One of the ambient light sensing comparator pins (CMP_IN)
is always available. The second pin (D6/CMP_IN2) can be
activated rather than connecting an LED to D6. Activating
the CMP_IN2 function of the pin is accomplished through
Bit CMP2_SEL in Register CFGR. Therefore, when Bit CMP2_SEL
is set to 0, Pin D6/CMP_IN2 is programmed as a current sink.
When Bit CMP2_SEL is set to 1, Pin D6/CMP_IN2 becomes
the input for a second phototransistor.
These comparators have two programmable trip points (L2 and
L3) that select among three of the backlight operation modes
(daylight, office, and dark) based on the ambient lighting
conditions.
The L3 comparator controls the dark-to-office mode transition.
The L2 comparator controls the office-to-daylight transition
(see Figure 38). The currents for the different lighting modes
are defined in the BLMXx and BLDMx registers (see the
Backlight Operating Levels section).
BRIGHTNESS
L3 L2
DARK OFFICE DAYLIGHT
0 LUX
0A
L2_OUT = 1
L3_OUT = 1
L2_OUT = 1
L3_OUT = 0
L2_OUT = 0
L3_OUT = 0
07967-023
Figure 38. Light Sensor Modes Based on the Detected Ambient Light Level
Each light sensor comparator uses an external capacitor together
with an internal reference current source to form an analog-to-
digital converter (ADC) that samples the output of the external
photosensor. The ADC result is fed into two programmable trip
comparators. The ADC has an input range of 0 µA to 1080 µA
(typical).
L2_HYS
L2_TRIP
L3_TRIP
L3_HYS
FILTER
SETTINGS
ADC
PHOTO
SENSOR
OUTPUT
L2_EN
L3_EN
L2_OUT
L3_OUT
07967-024
Figure 39. Ambient Light Sensing and Trip Comparators
The L2_CMPR detects when the photosensor output has dropped
below the programmable L2_TRP point (Register 0x1D). If this
event occurs, then the L2_OUT status signal is set. L2_CMPR
contains programmable hysteresis, meaning that the photo-
sensor output must rise above L2_TRP + L2_HYS before
L2_OUT clears. L2_CMPR is enabled via the L2_EN bit. The
L2_TRP and L2_HYS values of L2_CMPR can be set between
0 µA and 1080 µA (typical) in steps of 4.3 µA (typical).
The L3_CMPR detects when the photosensor output has
dropped below the programmable L3_TRP point (Register 0x1F).
If this event occurs, the L3_OUT status signal is set. L3_CMPR
ADP8860
Rev. 0 | Page 20 of 52
contains programmable hysteresis, meaning that the photo-
sensor output must rise above L3_TRP + L3_HYS before
L3_OUT clears. L3_CMPR is enabled via the L3_EN bit. The
L3_TRP and L3_HYS values of L3_CMPR can be set between
0 µA and 137.7 µA (typical) in steps of 0.54 µA (typical).
L2_TRP
L2_HYS
L3_TRP
L3_HYS
1 10 100 1000
ADC RANGE (µA)
07967-025
Figure 40. Comparator Ranges
Note that the full-scale value of the L2_TRP and L2_HYS
registers is 250 (decimal). Therefore, if the value of L2_TRP +
L2_HYS exceeds 250, the comparator output is unable to
deassert. For example, if L2_TRP is set at 204 (80% of the full-
scale value, or approximately 0.80 × 1080 A = 864 A), then
L2_HYS must be set at less than 46 (250 − 204 = 46). If it is not,
then the L2_HYS + L2_TRP exceeds 250 and the L2_CMPR
comparator is never allowed to go low.
When both phototransistors are enabled and programmed
in automatic mode (through Bit L3_EN and Bit L2_EN in
Register 0x1B and Register 0x1C), the user application needs
to determine which of the comparator outputs to use, selecting
Bit SEL_AB in Register 0x04 for automatic light sensing
transitions. For example, the user’s software may select the
comparator of the phototransistor exposed to higher light
intensity to control the transition between the programmed
backlight intensity levels.
The L2_CMPR and L3_CMPR comparators can be enabled
independently of each other, or can operate simultaneously. A
single conversion from each ADC takes 80 ms (typical). When
CMP_AUTOEN is set for automatic backlight adjustment (see
the Automatic Backlight Adjustment section), the ADC and
comparators run continuously. If the backlight is disabled and
at least one independent sink is enabled, it is possible to use the
light sensor comparators in a single shot mode. A single shot
read of the photocomparators is performed by setting the
FORCE_RD bit. After the single shot measurement is completed,
the internal state machine clears the FORCE_RD bit.
The interrupt flags (CMP_INT and CMP_INT2) can be used to
notify the system when either L2 or L3 changes state. Refer to
the Interrupts section for more information.
AUTOMATIC BACKLIGHT ADJUSTMENT
The ambient light sensor comparators can automatically
transition the backlight between one of its three operating
levels. To enable this mode, set the CMP_AUTOEN bit in
Register 0x01.
When enabled, the internal state machine takes control of the
BLV bits and changes them based on the L2_OUT and L3_OUT
status bits. When L2_OUT is set high, it indicates that the
ambient light conditions have dropped below the L2_TRP point
and the backlight should move to its office (L2) level. When
L3_OUT is set high, it indicates that ambient light conditions
have dropped below the L3_TRP point and the backlight should
move to its dark (L3) level. Tabl e 6 shows the relationship
between backlight operation and the ambient light sensor
comparator outputs.
The L3_OUT status bit has greater priority; therefore, the
backlight operates at L3 (dark) even if L2_OUT is set.
Filter times of between 80 ms and 10 sec can be programmed
for the comparators (Register 0x1B and Register 0x1C) before
they change state.
Table 6. Comparator Output Truth Table
CMP_AUTOEN L3_OUT L2_OUT Backlight Operation
0 X1 X
1 BLV can be manually set
by the user
1 0 0 BLV = 00, backlight
operates at L1 (daylight)
1 0 1 BLV = 01, backlight
operates at L2 (office)
1 1 X1 BLV = 10, backlight
operates at L3 (dark)
1 X is the don’t care bit.
INDEPENDENT SINK CONTROL
Each of the seven LEDs can be configured (in Register 0x05) to
operate as either part of the backlight or to operate as an indepen-
dent sink current (ISC). Each ISC can be enabled independently
and has its own current level. All ISCs share the same fade in
rates, fade out rates, and fade law.
The ISCs have additional timers to facilitate blinking functions.
A shared on timer (SCON) used in conjunction with the off
timers of each ISC (SC1OFF, SC2OFF, SC3OFF, SC4OFF,
SC5OFF, SC6OFF, and SC7OFF) allow the LED current sinks to
be configured in various blinking modes. The on timer can be
set to four different settings: 0.2 sec, 0.6 sec, 0.8 sec, and 1.2 sec.
The off timers have four different settings: disabled, 0.6 sec,
1.2 sec, and 1.8 sec. Blink mode is activated by setting the off
timers to any setting other than disabled.
ADP8860
Rev. 0 | Page 21 of 52
SCx_EN
Program all fade, on, and off timers before enabling any of the
LED current sinks. If ISCx is on during a blink cycle and
SCx_EN is cleared, it turns off (or fades to off if fade out is
enabled). If ISCx is off during a blink cycle and SCx_EN is
cleared, it stays off.
MAX
SCx
CURRENT
FADE-IN FADE-OUT FADE-IN FADE-OUT
ON TIME ON TIME
OFF
TIME
OFF
TIME
SET BY USER
07967-026
Figure 41. Independent Sink Blink Mode with Fading
SHORT-CIRCUIT PROTECTION MODE
The ADP8860 can protect against short circuits on the output
(VOUT). Short-circuit protection (SCP) is activated at the point
when VOUT < 55% of VIN. Note that this SCP sensing is disabled
during both start-up and restart attempts (fault recovery). SCP
sensing reenables 4 ms (typical) after activation. During a short-
circuit fault, the device enters a low current consumption state
and an interrupt flag is set. The device can be restarted at any
time after receiving a short-circuit fault by simply rewriting
nSTBY = 1. It then repeats another complete soft start sequence.
Note that the value of the output capacitance (COUT) should be
small enough to allow VOUT to reach approximately 55%
(typical) of VIN within the 4 ms (typical) time. If COUT is too
large, the device inadvertently enters short-circuit protection.
OVERVOLTAGE PROTECTION
Overvoltage protection (OVP) is implemented on the output.
There are two types of overvoltage events: normal (no fault) and
abnormal (from a fault or sudden load change).
Normal Overvoltage
In a normal (no fault) overvoltage, the output voltage approaches
VOUT(REG) (4.9 V typical) during normal operation. This is not
caused by a fault or load change, but it is simply a consequence
of the input voltage times the gain reaching the same level as the
clamped output voltage (VOUT(REG)). To prevent this type of over-
voltage, the ADP8860 detects when the output voltage rises to
VOUT(REG). It then increases the effective ROUT of the gain stage to
reduce the voltage that is delivered. This effectively regulates
VOUT to VOUT(REG); however, there is a limit to the effect that this
system can have on regulating VOUT. It is designed only for normal
operation and it is not intended to protect against faults or sudden
load changes. When the output voltage is regulated to VOUT(REG)
no interrupt is set and the operation is transparent to the LEDs
and the overall application.
Abnormal Overvoltage
Because of the open-loop behavior of the charge pump as well
as how the gain transitions are computed, a sudden load change
or fault can abnormally force VOUT beyond 6 V. This causes an
abnormal overvoltage situation. If the event happens slowly
enough, the system first tries to regulate the output to 4.9 V as
in a normal overvoltage scenario. However, if this is not
sufficient, or if the event happens too quickly, then the
ADP8860 enters overvoltage protection (OVP) mode when
VOUT exceeds the OVP threshold (typically 5.8 V). In the OVP
mode, only the charge pump is disabled to prevent VOUT from
rising too high. The current sources and all other device
functionality remain intact. When the output voltage falls by
about 500 mV (to 5.3 V typical), the charge pump resumes
operation. If the fault or load step recurs, the process may
repeat. An interrupt flag is set at each OVP instance.
THERMAL SHUTDOWN/OVERTEMPERATURE
PROTECTION
If the die temperature of the ADP8860 rises above a safe limit
(150°C typical), the controllers enter thermal shutdown (TSD)
protection mode. In this mode, most of the internal functions
shut down, the part enters standby, and the TSD_INT interrupt
is set. When the die temperature decreases below ~130°C, the
part can be restarted. To restart the part, simply remove it from
standby. No interrupt is generated when the die temperature
falls below 130°C. However, if the software clears the pending
TSD_INT interrupt and the temperature remains above 130°C,
another interrupt is generated.
The complete state machine for these faults (SCP, OVP, and
TSD) is shown in Figure 42.
ADP8860
Rev. 0 | Page 22 of 52
WAIT
100µs (TYP)
G = 2
G = 3/2
0
0
1
1
1
1
0
VOUT > VOVP
OVP FAULT
1
0
1
0
VOUT > VOUT(REG)
TRY TO
REGULATE
VOUT TO
VOUT(REG)
VOUT > VOVP
OVP FAULT
VOUT < VOVP –
VOVP (HYS)
0
1
0
1
1
0
VOUT > VOVP
OVP FAULT
0
1
0
1
1
0
EXIT
STARTUP
G = 1
STBY
1
0
VOUT < VOUT(SC)
0
SCP FAULT
EXIT STBY
STARTUP:
CHARGE
VIN TO VOUT
VOUT > VOUT(START)
DIE TEMP > TSD
0
TSD FAULT
DIE TEMP <
TSD – TSD(HYS)
MIN (VD1:D7)
< VHR(UP)
MIN (VD1:D7)
< VHR(UP)
MIN (VD1:D7)
> VDMAX
MIN (VD1:D7)
> VDMAX
1
0
EXIT STBY
WAIT
100µs (TYP)
WAIT
100µs (TYP)
VOUT < VOVP –
VOVP (HYS)
VOUT > VOUT(REG)
TRY TO
REGULATE
VOUT TO NOTES
VOUT < VOVP –
VOVP(HYS)
1
VOUT(REG) 1. VDMAX IS THE CALCULATED GAIN DOWN TRANSITION POINT.
07967-027
0
Figure 42. Fault State Machine
ADP8860
Rev. 0 | Page 23 of 52
INTERRUPTS
There are five interrupt sources available on the ADP8860.
• Main light sensor comparator: CMP_INT sets every time
the main light sensor comparator detects a threshold (L2
or L3) transition (rising or falling conditions).
• Sensor Comparator 2: CMP2_INT interrupt works the
same way as CMP_INT, except the sensing input derives
from the second light sensor. The programmable thresholds
are the same as the main light sensor comparator.
• Overvoltage protection: OVP_INT is generated when the
output voltage exceeds 5.8 V (typical).
• Thermal shutdown circuit: An interrupt (TSD_INT) is
generated when entering overtemperature protection.
• Short-circuit detection: SHORT_INT is generated when
the device enters short-circuit protection mode.
The interrupt (if any) that appears on the nINT pin is deter-
mined by the bits mapped in Register INTR_EN. To clear an
interrupt, write a 1 to the interrupt in the MDCR2 register or
reset the part. Reading the interrupt, or writing a 0, has no effect.
ADP8860
Rev. 0 | Page 24 of 52
07967-14
APPLICATIONS INFORMATION
The ADP8860 allows the charge pump to operate efficiently
with a minimum of external components. Specifically, the user
must select an input capacitor (CIN), output capacitor (COUT),
and two charge pump fly capacitors (C1 and C2). CIN should be
1 F or greater. The value must be high enough to produce a
stable input voltage signal at the minimum input voltage and
maximum output load. A 1 F capacitor for COUT is recommended.
Larger values are permissible, but care must be exercised to
ensure that VOUT charges above 55% (typical) of VIN within
4 ms (typical). See the Short-Circuit Protection Mode section
for more details.
For best practice, it is recommended that the two charge pump
fly capacitors be 1 F; larger values are not recommended and
smaller values may reduce the ability of the charge pump to
deliver maximum current. For optimal efficiency, the charge
pump fly capacitors should have low equivalent series resistance
(ESR). Low ESR X5R or X7R capacitors are recommended for
all four components. Use voltage ratings of 10 V or greater for
these capacitors.
If one or both ambient light sensor comparator inputs (CMP_IN
and D6/CMP_IN2) are used, a small capacitor (0.1 F is
recommended) must be connected from the input to ground.
Any color of LED can be used if the Vf (forward voltage) is less
than 4.1 V. However, using lower Vf LEDs reduces the input
power consumption by allowing the charge pump to operate at
lower gain states.
The equivalent circuit model for a charge pump is shown in
Figure 43.
0
V
DX
C
OUT
G × V
IN
R
OUT
V
OUT
I
OUT
Figure 43. Charge Pump Equivalent Circuit Model
The input voltage is multiplied by the gain (G) and delivered to
the output through an effective resistance (ROUT). The output
current flows through ROUT and produces an IR drop to yield
VOUT = G ×VIN − IOUT × ROUT(G) (5)
The ROUT term is a combination of the RDSON resistance for the
switches used in the charge pump and a small resistance that
accounts for the effective dynamic charge pump resistance. The
ROUT level changes based upon the gain (the configuration of the
switches). Typical ROUT values are given in Table 1 and Figure 13
and Figure 14.
VOUT is also equal to the largest Vf of the LEDs that are used
plus the voltage drop across the regulating current source. This
gives
VOUT = Vf(MAX) + VDx (6)
Combining Equation 5 and Equation 6 gives
VIN = (Vf(MAX) + VDx + IOUT × ROUT(G))/G (7)
This equation is useful for calculating approximate bounds for
the charge pump design.
Determining the Transition Point of the Charge Pump
Consider the following design example where:
Vf(MAX) = 3.7 V
IOUT = 140 mA (7 LEDs at 20 mA each)
ROUT (G = 1.5×) = 3 Ω (obtained from Figure 13)
At the point of a gain transition, VDx = VHR(UP), Tabl e 1 gives the
typical value of VHR(UP) as 0.2 V. Therefore, the input voltage
level when the gain transitions from 1.5× to 2× is
VIN = (3.7 V + 0.2 V + 140 mA × 3 Ω)/1.5 = 2.88 V
LAYOUT GUIDELINES
• For optimal noise immunity, place the CIN and COUT
capacitors as close as possible to their respective pins.
These capacitors should share a short ground trace. If the
LEDs are a significant distance from the VOUT pin, another
capacitor on VOUT, placed closer to the LEDs, is advisable.
• For optimal efficiency, place the charge pump fly capacitors
as close to the part as possible.
• The ADP8860 does not distinguish between power ground
and analog ground. Therefore, both ground pins can be
connected directly together. It is recommended that these
ground pins be connected at the ground for the input and
output capacitors.
• If using the LFCSP package, the exposed pad must be
soldered at the board to the GND1 and/or GND2 pin(s).
• Unused diode pins (Pin D1 to Pin D7) can be connected to
ground, VOUT, or remain floating. However, the unused
diode current sinks must be disabled by setting them as
independent sinks in Register 0x05 and then disabling
them in Register 0x10. If they are not disabled, the charge
pump efficiency may suffer.
• If the CMP_IN phototransistor input is not used, it can be
connected to ground or remain floating.
• If the interrupt pin (nINT) is not used, connect it to
ground or leave it floating. Never connect it to a voltage
supply, except through a ≥1 k series resistor.
ADP8860
Rev. 0 | Page 25 of 52
• The ADP8860 has an integrated noise filter on the nRST
pin. Under normal conditions, it is not necessary to filter
the reset line. However, if exposed to an unusually noisy
signal, then it is beneficial to add a small RC filter or
bypass capacitor on this pin. If the nRST pin is not used, it must
be pulled well above the VIH(MIN) level (see Table 1). Do not allow
the nRST pin to float.
EXAMPLE CIRCUITS
V
07967-028
D3
D1
E3
D2
E4
D3
D4
D4
C4
D5
B4
D6
B3
D7
C3
CMP_IN
V
OUT
OPTIONAL
PHOTOSENSOR
PHOTOSENSOR
ALS
0.1µF
0.1µF
E1
VDDIO
nRST
C2
VDDIO
SDA
E2
VDDIO
SCL
D2
VDDIO
nINT
A3
V
IN
1µF
A4
GND1
D1
GND2
B1
C2+
B2
C2–
C2
1µF
A1
C1+
C1
C1–
C1
1µF
V
OUT
1µF
A2
ADP8860
Figure 44. Generic Application Schematic
KEYPAD LIGHT
UP TO 10 LEDs (6mA EACH)
60mA MAX TOTAL CURRENT
ACCESSORY
LIGHTS OR
SUB-DISPLAY BL
PH1
MAIN
PHOTOSENSOR
PH2
OPTIONAL
PHOTOSENSOR
0
7967-029
D3
D1
DL1
E3
D2
DL2
E4
D3
DL3
D4
D4
DL4
C4
D5
DL5
B4
D6/
CMP_IN2
DL6
B3
D7
C3
CMP_IN
E1
R1 R2 R3 R4
VDDIO
C2
SDA
E2
SCL
D2
B1
C2+
B2
C2–
A1
C1+
VOUT
GND2
C1
C1–
ADP8860
VIN
GND1
A3
A4
V
IN
A2
D1
DISPLAY BACKLIGHT
DL7
R5
DL8
R6
DL17
R15
2.8V
nRST
nINT
nRST
nINT
0.1µF
0.1µF
C2
1µF
C1
1µF
1µF
1µF
I
2
C
CONTROL
SIGNALS
Figure 45. Application Schematic with Keypad Light Control
ADP8860
Rev. 0 | Page 26 of 52
I2C PROGRAMMING AND DIGITAL CONTROL
The ADP8860 provides full software programmability to
facilitate its adoption in various product architectures. The
default I2C address is 0101010x (x = 0 during write, x = 1 during
read). Therefore, the default write address is 0x54 and the read
address is 0x55.
Note the following general behavior of registers:
• All registers are set to their default values during reset or
after a UVLO event.
• All registers are read/write unless otherwise specified.
• Unused bits are read as zero.
The following tables provide register and bit descriptions. The
reset value for all bits in the bit map tables is all 0s, except in
Table 9 (see Table 9 for its unique reset value). Wherever the
acronym N/A appears in the tables, it means not applicable.
0 1 0 1 0 1 0
R/W
0 0 0
ST SP
0 = WRITE
1 = READ
CHIP ADDRESS REG ADDRESS DATA
ACK
ACK
ACK
07967-030
Figure 46. I2C Command Sequence
Table 7. Register Set Definitions
Address Register Name Description
0x00 MFDVID Manufacturer and device ID
0x01 MDCR Device mode and status
0x02 MDCR2 Device mode and Status Register 2
0x03 INTR_EN Interrupts enable
0x04 CFGR Configuration register
0x05 BLSEN Sink enable backlight or independent
0x06 BLOFF Backlight off timeout
0x07 BLDIM Backlight dim timeout
0x08 BLFR Backlight fade in and out rates
0x09 BLMX1 Backlight (Brightness Level 1—daylight) maximum current
0x0A BLDM1 Backlight (Brightness Level 1—daylight) dim current
0x0B BLMX2 Backlight (Brightness Level 2—office) maximum current
0x0C BLDM2 Backlight (Brightness Level 2—office) dim current
0x0D BLMX3 Backlight (Brightness Level 3—dark) maximum current
0x0E BLDM3 Backlight (Brightness Level 3—dark) dim current
0x0F ISCFR Independent sink current fade control register
0x10 ISCC Independent sink current control register
0x11 ISCT1 Independent Sink Current Timer Register LED[7:5]
0x12 ISCT2 Independent Sink Current Timer Register LED[4:1]
0x13 ISCF Independent sink current fade register
0x14 ISC7 Independent Sink Current LED7
0x15 ISC6 Independent Sink Current LED6
0x16 ISC5 Independent Sink Current LED5
0x17 ISC4 Independent Sink Current LED4
0x18 ISC3 Independent Sink Current LED3
0x19 ISC2 Independent Sink Current LED2
0x1A ISC1 Independent Sink Current LED1
0x1B CCFG Comparator configuration
0x1C CCFG2 Second comparator configuration
0x1D L2_TRP L2 comparator reference
0x1E L2_HYS L2 hysteresis
0x1F L3_TRP L3 comparator reference
ADP8860
Rev. 0 | Page 27 of 52
Address Register Name Description
0x20 L3_HYS L3 hysteresis
0x21 PH1LEVL First phototransistor ambient light level—low byte register
0x22 PH1LEVH First phototransistor ambient light level—high byte register
0x23 PH2LEVL Second phototransistor ambient light level—low byte register
0x24 PH2LEVH Second phototransistor ambient light level—high byte register
Table 8. Register Map
Addr Reg. Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
0x00 MFDVID Manufacture ID Device ID
0x01 MDCR Reserved INT_CFG NSTBY DIM_EN Reserved SIS_EN CMP_AUTOEN BLEN
0x02 MDCR2 Reserved SHORT_INT TSD_INT OVP_INT CMP2_INT CMP_INT
0x03 INTR_EN Reserved SHORT_IEN TSD_IEN OVP_IEN CMP2_IEN CMP_IEN
0x04 CFGR Reserved SEL_AB CMP2_SEL BLV Law FOVR
0x05 BLSEN Reserved D7EN D6EN D5EN D4EN D3EN D2EN D1EN
0x06 BLOFF Reserved OFFT
0x07 BLDIM Reserved DIMT
0x08 BLFR BL_FO BL_FI
0x09 BLMX1 Reserved BL1_MC
0x0A BLDM1 Reserved BL1_DC
0x0B BLMX2 Reserved BL2_MC
0x0C BLDM2 Reserved BL2_DC
0x0D BLMX3 Reserved BL3_MC
0x0E BLDM3 Reserved BL3_DC
0x0F ISCFR Reserved SC_LAW
0x10 ISCC Reserved SC7_EN SC6_EN SC5_EN SC4_EN SC3_EN SC2_EN SC1_EN
0x11 ISCT1 SCON SC7OFF SC6OFF SC5OFF
0x12 ISCT2 SC4OFF SC3OFF SC2OFF SC1OFF
0x13 ISCF SCFO SCFI
0x14 ISC7 SCR SCD7
0x15 ISC6 Reserved SCD6
0x16 ISC5 Reserved SCD5
0x17 ISC4 Reserved SCD4
0x18 ISC3 Reserved SCD3
0x19 ISC2 Reserved SCD2
0x1A ISC1 Reserved SCD1
0x1B CCFG FILT FORCE_RD L3_OUT L2_OUT L3_EN L2_EN
0x1C CCFG2 FILT2 FORCE_RD2 L3_OUT2 L2_OUT2 L3_EN2 L2_EN2
0x1D L2_TRP L2_TRP
0x1E L2_HYS L2_HYS
0x1F L3_TRP L3_TRP
0x20 L3_HYS L3_HYS
0x21 PH1LEVL PH1LEV_LOW
0x22 PH1LEVH Reserved PH1LEV_HIGH
0x23 PH2LEVL PH2LEV_LOW
0x24 PH2LEVH Reserved PH2LEV_HIGH
ADP8860
Rev. 0 | Page 28 of 52
Manufacturer and Device ID (MFDVID)—Register 0x00
This is a read-only register.
Table 9. MFDVID Manufacturer and Device ID Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Manufacture ID Device ID
0 0 0 0 0 1 1 1
Mode Control Register (MDCR)—Register 0x01
Table 10. MDCR Mode Control Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved INT_CFG nSTBY DIM_EN Reserved SIS_EN CMP_AUTOEN BL_EN
Table 11. Bit Descriptions for the MDCR Register
Bit Name Bit No. Description
N/A 7 Reserved.
INT_CFG 6 Interrupt configuration.
1 = processor interrupt deasserts for 50 μs and reasserts with pending events.
0 = processor interrupt remains asserted if the host tries to clear the interrupt while there is a pending event.
nSTBY 5 1 = device is in active mode.
0 = device is in standby mode, only the I2C interface is enabled.
DIM_EN 4 DIM_EN is set by the hardware after a DIM timeout. The user may also force the backlight into DIM mode by
asserting this bit. DIM mode can only be entered if BL_EN is also enabled.
1 = backlight is operating at the DIM current level (BL_EN must also be asserted).
0 = backlight is not in DIM mode.
N/A 3 Reserved.
SIS_EN 2 Synchronous independent sinks enable.
1 = enables all LED current sinks designated as independent sinks. All of the ISC enable bits must be cleared; if
any of the SC_EN bits in Register 0x10 are set, this bit has no effect.
0 = disables all sinks designated as independent sinks. All of the ISC enable bits must be cleared; if any of the
SC_EN bits are set in Register 0x10, this bit has no effect.
CMP_AUTOEN 1 1 = backlight automatically responds to the comparator outputs (L2_OUT and L3_OUT). L2_EN and/or L3_EN
must be set for this to function. BLV values in Register 0x04 are overridden.
0 = backlight does not autorespond to comparator level changes. The user can manually select backlight
operating levels using Bit BLV in Register 0x04.
BL_EN 0 1 = backlight is enabled (nSTBY must also be asserted).
0 = backlight is disabled.
ADP8860
Rev. 0 | Page 29 of 52
Mode Control Register 2 (MDCR2)—Register 0x02
Table 12. MDCR2 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SHORT_INT TSD_INT OVP_INT CMP2_INT CMP_INT
Table 13. Bit Descriptions for the MDCR2 Register
Bit Name Bit No. Description1
N/A 7:5 Reserved.
SHORT_INT 4 Short-circuit error.
1 = a short-circuit or overload condition on VOUT was detected.
0 = no short-circuit or overload condition has been detected.
TSD_INT 3 Thermal shutdown.
1 = the device temperature has exceeded 150°C (typical).
0 = no overtemperature condition has been detected.
OVP_INT 2 Overvoltage interrupt.
1 = VOUT has exceeded VOVP.
0 = VOUT has not exceeded VOVP.
CMP2_INT 1 1 = indicates that the second ALS comparator (CMP_IN2) has changed state.
0 = the second sensor comparator has not triggered.
CMP_INT 0 1 = indicates that the main ALS comparator (CMP_IN) has changed state.
0 = the main sensor comparator has not triggered.
1 Interrupt bits are cleared by writing a 1 to the flag; writing a 0 or reading the flag has no effect.
Interrupt Enable (INTR_EN)—Register 0x03
Table 14. INTR_EN Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SHORT_IEN TSD_IEN OVP_IEN CMP2_IEN CMP_IEN
Table 15. Bit Descriptions for the INTR_EN Register
Bit Name Bit No. Description
N/A 7:5 Reserved.
SHORT_IEN 4 Short-circuit interrupt is enabled. When the SHORT_INT status bit is set after an error condition, an interrupt is
raised to the host if the SHORT_IEN flag is enabled.
1 = the short-circuit interrupt is enabled.
0 = the short-circuit interrupt is disabled (the SHORT_INT flag continues to assert).
TSD_IEN 3 Thermal shutdown interrupt is enabled. When the TSD_INT status bit is set after an error condition, an interrupt is
raised to the host if the TSD_IEN flag is enabled.
1 = the thermal shutdown interrupt is enabled.
0 = the thermal shutdown interrupt is disabled (the TSD_INT flag continues to assert).
OVP_IEN 2 Overvoltage interrupt enabled. When the OVP_INT status bit is set after an error condition, an interrupt is raised to
the host if the OVP_IEN flag is enabled.
1 = the overvoltage interrupt is enabled.
0 = the overvoltage interrupt is disabled (the OVP_INT flag continues to assert).
CMP2_IEN 1 When the CMP2_INT status bit is set after an enabled comparator trips, an interrupt is raised if the CMP2_IEN flag is
enabled.
1 = the second phototransistor comparator interrupt is enabled.
0 = the second phototransistor comparator interrupt is disabled (the CMP2_INT flag continues to assert).
ADP8860
Rev. 0 | Page 30 of 52
Bit Name Bit No. Description
CMP_IEN 0 When the CMP_INT status bit is set after an enabled comparator trips, an interrupt is raised if the CMP_IEN flag is
enabled.
1 = the main comparator interrupt is enabled.
0 = the main comparator interrupt is disabled (the CMP_INT flag continues to assert).
BACKLIGHT REGISTER DESCRIPTIONS
Configuration Register (CFGR)—Register 0x04
Table 16. CFGR Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SEL_AB CMP2_SEL BLV Law FOVR
Table 17. Bit Descriptions for the CFGR Register
Bit Name Bit No. Description
N/A 7 Reserved.
SEL_AB 6 1 = selects the second phototransistor (CMP_IN2) to control the backlight.
0 = selects the main phototransistor (CMP_IN) to control the backlight.
CMP2_SEL 5 1 = the second phototransistor is enabled; the current sink on D6 is disabled.
0 = the second phototransistor is disabled.
BLV 4:3 Brightness level. This field indicates the brightness level at which the device is operating. The software may force the
backlight to operate at one of the three brightness levels. Setting CMP_AUTOEN high (Register 0x01) sets these
values automatically and overwrites any previously written values.
00 = Level 1 (daylight).
01 = Level 2 (office).
10 = Level 3 (dark).
11 = off (backlight set to 0 mA).
Law 2:1 Backlight transfer law.
00 = linear law DAC, linear time steps.
01 = square law DAC, linear time steps.
10 = square law DAC, nonlinear time steps (Cubic 10).
11 = square law DAC, nonlinear time steps (Cubic 11).
FOVR 0 Backlight fade override.
1 = the backlight fade override is enabled.
0 = the backlight fade override is disabled.
Backlight Sink Enable (BLSEN)—Register 0x05
Table 18. BLSEN Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved D7EN D6EN D5EN D4EN D3EN D2EN D1EN
Table 19. Bit Descriptions for the BLSEN Register
Bit Name Bit No. Description
N/A 7 Reserved.
D7EN 6 Diode 7 backlight sink enable.
1 = selects LED7 as an independent sink.
0 = connects LED7 sink to backlight enable (BL_EN).
D6EN 5 Diode 6 backlight sink enable.
1 = selects LED6 as an independent sink.
0 = connects LED6 sink to backlight enable (BL_EN).
ADP8860
Rev. 0 | Page 31 of 52
Bit Name Bit No. Description
D5EN 4 Diode 5 backlight sink enable.
1 = selects LED5 as an independent sink.
0 = connects LED5 sink to backlight enable (BL_EN).
D4EN 3 Diode 4 backlight sink enable.
1 = selects LED4 as independent sink.
0 = connects LED4 sink to backlight enable (BL_EN).
D3EN 2 Diode 3 backlight sink enable.
1 = selects LED3 as independent sink.
0 = connects LED3 sink to backlight enable (BL_EN).
D2EN 1 Diode 2 backlight sink enable.
1 = selects LED2 as independent sink.
0 = connects LED2 sink to backlight enable (BL_EN).
D1EN 0 Diode 1 backlight sink enable.
1 = selects LED1 as independent sink.
0 = connects LED1 sink to backlight enable (BL_EN).
Backlight Off Timeout (BLOFF)—Register 0x06
Table 20. BLOFF Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved OFFT
Table 21. Bit Descriptions for the BLOFF Register
Bit Name Bit No. Description
N/A 7 Reserved.
OFFT 6:0 Backlight off timeout. After the off timeout (OFFT) period, the backlight turns off. If the dim timeout (DIMT) is
enabled, the off timeout starts after the dim timeout.
0000 = timeout disabled
0000001 = 1 sec
0000010 = 2 sec
0000011 = 3 sec
…
1111111 = 127 sec
Backlight Dim Timeout (BLDIM)—Register 0x07
Table 22. BLDIM Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved DIMT
Table 23. Bit Descriptions for the BLDIM Register
Bit Name Bit No. Description
N/A 7 Reserved.
DIMT 6:0 Backlight dim timeout. After the dim timeout (DIMT) period, the backlight is set to the dim current value. The dim
timeout starts after backlight reaches the maximum current.
0000 = timeout disabled
0000001 = 1 sec
0000010 = 2 sec
0000011 = 3 sec
…
1111111 = 127 sec
ADP8860
Rev. 0 | Page 32 of 52
Backlight Fade (BLFR)—Register 0x08
Table 24. BLFR Backlight Fade Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
BL_FO BL_FI
Table 25. Bit Descriptions for the BLFR Register
Bit
Name Bit No. Description
BL_FO 7:4 Backlight fade out rate. If the fade out is disabled (BL_FO = 0000), the backlight changes instantly (within 100 ms). If the
fade out rate is set, the backlight fades from its current value to the dim or the off value. The times listed for BL_FO are
for a full-scale fade out (30 mA to 0 mA). Fades between closer current values reduce the fade time. See the Automated
Fade In and Fade Out section for more information.
0000 = 0.1 sec (fade out disabled)1
0001 = 0.3 sec
0010 = 0.6 sec
0011 = 0.9 sec
0100 = 1.2 sec
0101 = 1.5 sec
0110 = 1.8 sec
0111 = 2.1 sec
1000 = 2.4 sec
1001 = 2.7 sec
1010 = 3.0 sec
1011 = 3.5 sec
1100 = 4.0 sec
1101 = 4.5 sec
1110 = 5.0 sec
1111 = 5.5 sec
BL_FI 3:0 Backlight fade in rate. If the fade in is disabled (BL_FI = 0000), the backlight changes instantly (within 100 ms). If the
fade in rate is set, the backlight fades from its current value to its maximum when the backlight is turned on. The times
listed for BL_FI are for a full-scale fade in (0 mA to 30 mA). Fades between closer current values reduce the fade time.
See the Automated Fade In and Fade Out section for more information.
0000 = 0.1 sec (fade in disabled)1
0001 = 0.3 sec
0010 = 0.6 sec
0011 = 0.9 sec
…
1111 = 5.5 sec
1 When fade in and fade out are disabled, the backlight does not instantaneously fade, but instead, fades rapidly within about 100 ms.
ADP8860
Rev. 0 | Page 33 of 52
Backlight Level 1 (Daylight) Maximum Current Register (BLMX1)—Register 0x09
Table 26. BLMX1 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved BL1_MC
Table 27. Bit Descriptions for the BLMX1 Register
Bit Name Bit No. Description
N/A 7 Reserved.
BL1_MC 6:0 Backlight maximum Level 1 (daylight) current. The backlight maximum current can be set according to
the linear or square law function, as follows (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.708 0.017
… … …
1111111 30 30
Table 28. Linear and Square Law Currents Per DAC Code
DAC Code Linear Law (mA) Square Law1 (mA)
0x00 0 0.000
0x01 0.236 0.002
0x02 0.472 0.007
0x03 0.709 0.017
0x04 0.945 0.030
0x05 1.181 0.047
0x06 1.417 0.067
0x07 1.654 0.091
0x08 1.890 0.119
0x09 2.126 0.151
0x0A 2.362 0.186
0x0B 2.598 0.225
0x0C 2.835 0.268
0x0D 3.071 0.314
0x0E 3.307 0.365
0x0F 3.543 0.419
0x10 3.780 0.476
0x11 4.016 0.538
0x12 4.252 0.603
0x13 4.488 0.671
0x14 4.724 0.744
0x15 4.961 0.820
0x16 5.197 0.900
0x17 5.433 0.984
0x18 5.669 1.071
0x19 5.906 1.163
0x1A 6.142 1.257
0x1B 6.378 1.356
0x1C 6.614 1.458
0x1D 6.850 1.564
0x1E 7.087 1.674
DAC Code Linear Law (mA) Square Law1 (mA)
0x1F 7.323 1.787
0x20 7.559 1.905
0x21 7.795 2.026
0x22 8.031 2.150
0x23 8.268 2.279
0x24 8.504 2.411
0x25 8.740 2.546
0x26 8.976 2.686
0x27 9.213 2.829
0x28 9.449 2.976
0x29 9.685 3.127
0x2A 9.921 3.281
0x2B 10.157 3.439
0x2C 10.394 3.601
0x2D 10.630 3.767
0x2E 10.866 3.936
0x2F 11.102 4.109
0x30 11.339 4.285
0x31 11.575 4.466
0x32 11.811 4.650
0x33 12.047 4.838
0x34 12.283 5.029
0x35 12.520 5.225
0x36 12.756 5.424
0x37 12.992 5.627
0x38 13.228 5.833
0x39 13.465 6.043
0x3A 13.701 6.257
0x3B 13.937 6.475
0x3C 14.173 6.696
0x3D 14.409 6.921
ADP8860
Rev. 0 | Page 34 of 52
DAC Code Linear Law (mA) Square Law1 (mA)
0x3E 14.646 7.150
0x3F 14.882 7.382
0x40 15.118 7.619
0x41 15.354 7.859
0x42 15.591 8.102
0x43 15.827 8.350
0x44 16.063 8.601
0x45 16.299 8.855
0x46 16.535 9.114
0x47 16.772 9.376
0x48 17.008 9.642
0x49 17.244 9.912
0x4A 17.480 10.185
0x4B 17.717 10.463
0x4C 17.953 10.743
0x4D 18.189 11.028
0x4E 18.425 11.316
0x4F 18.661 11.608
0x50 18.898 11.904
0x51 19.134 12.203
0x52 19.370 12.507
0x53 19.606 12.814
0x54 19.842 13.124
0x55 20.079 13.439
0x56 20.315 13.757
0x57 20.551 14.078
0x58 20.787 14.404
0x59 21.024 14.733
0x5A 21.260 15.066
0x5B 21.496 15.403
0x5C 21.732 15.743
0x5D 21.968 16.087
0x5E 22.205 16.435
DAC Code Linear Law (mA) Square Law1 (mA)
0x5F 22.441 16.787
0x60 22.677 17.142
0x61 22.913 17.501
0x62 23.150 17.863
0x63 23.386 18.230
0x64 23.622 18.600
0x65 23.858 18.974
0x66 24.094 19.351
0x67 24.331 19.733
0x68 24.567 20.118
0x69 24.803 20.507
0x6A 25.039 20.899
0x6B 25.276 21.295
0x6C 25.512 21.695
0x6D 25.748 22.099
0x6E 25.984 22.506
0x6F 26.220 22.917
0x70 26.457 23.332
0x71 26.693 23.750
0x72 26.929 24.173
0x73 27.165 24.599
0x74 27.402 25.028
0x75 27.638 25.462
0x76 27.874 25.899
0x77 28.110 26.340
0x78 28.346 26.784
0x79 28.583 27.232
0x7A 28.819 27.684
0x7B 29.055 28.140
0x7C 29.291 28.599
0x7D 29.528 29.063
0x7E 29.764 29.529
0x7F 30.000 30.000
1 Cubic 10 and Cubic 11 laws use the square law DAC setting but vary the time
step per DAC code (see ). Figure 31
ADP8860
Rev. 0 | Page 35 of 52
Backlight Level 1 (Daylight) Dim Current Register (BLDM1)—Register 0x0A
Table 29. BLDM1 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved BL1_DC
Table 30. Bit Descriptions for the BLDM1 Register
Bit Name Bit No. Description
N/A 7 Reserved.
BL1_DC 6:0 Backlight Level 1 (daylight) dim current. The backlight is set to the dim current value after a dim timeout or
if the DIM_EN flag is set by the user (see Table 28 for a complete list of values).
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
Backlight Level 2 (Office) Maximum Current Register (BLMX2)—Register 0x0B
Table 31. BLMX2 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved BL2_MC
Table 32. Bit Descriptions for the BLMX2 Register
Bit Name Bit No. Description
N/A 7 Reserved.
BL2_MC 6:0 Backlight Level 2 (office) maximum current (see Table 28 for a complete list of values).
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
ADP8860
Rev. 0 | Page 36 of 52
Backlight Level 2 (Office) Dim Current Register (BLDM2)—Register 0x0C
Table 33. BLDM2 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved BL2_DC
Table 34. Bit Descriptions for the BLDM2 Register
Bit Name Bit No. Description
N/A 7 Reserved.
BL2_DC 6:0 Backlight Level 2 (office) dim current. See Table 28 for a complete list of values. The backlight is set to the
dim current value after a dim timeout or if the DIM_EN flag is set by the user.
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
Backlight Level 3 (Dark) Maximum Current Register (BLMX3)—Register 0x0D
Table 35. BLMX3 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved BL3_MC
Table 36. Bit Descriptions for the BLMX3 Register
Bit Name Bit No. Description
N/A 7 Reserved.
BL3_MC 6:0 Backlight Level 3 (dark) maximum current. See Table 28 for a complete list of values.
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
ADP8860
Rev. 0 | Page 37 of 52
Backlight Level 3 (Dark) Dim Current Register (BLDM3)—Register 0x0E
Table 37. BLDM3 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved BL3_DC
Table 38. Bit Descriptions for the BLDM3 Register
Bit Name Bit No. Description
N/A 7 Reserved.
BL3_DC 6:0 Backlight Level 3 (dark) dim current. See Table 28 for a complete list of values. The backlight is set to the
dim current value after a dim timeout or if the DIM_EN flag is set by the user.
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
INDEPENDENT SINK REGISTER DESCRIPTIONS
Independent Sink Current Fade Control Register (ISCFR)—Register 0x0F
Table 39. ISCFR Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SC_LAW
Table 40. Bit Descriptions for the ISCFR
Bit Name Bit No. Description
N/A 7:2 Reserved.
SC_LAW 1:0 Independent sink current fade transfer law.
00 = linear law DAC, linear time steps.
01 = square law DAC, linear time steps.
10 = square law DAC, nonlinear time steps (Cubic 10).
11 = square law DAC, nonlinear time steps (Cubic 11).
Independent Sink Current Control (ISCC)—Register 0x10
Table 41. ISCC Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SC7_EN SC6_EN SC5_EN SC4_EN SC3_EN SC2_EN SC1_EN
Table 42. Bit Descriptions for the ISCC Register
Bit Name Bit No. Description
N/A 7 Reserved.
SC7_EN 6 This enable acts upon the LED7.
1 = SC7 is turned on.
0 = SC7 is turned off.
SC6_EN 5 This enable acts upon the LED6.
1 = SC6 is turned on.
0 = SC6 is turned off.
SC5_EN 4 This enable acts upon the LED5.
1 = SC5 is turned on.
0 = SC5 is turned off.
ADP8860
Rev. 0 | Page 38 of 52
Bit Name Bit No. Description
SC4_EN 3 This enable acts upon the LED4.
1 = SC4 is turned on.
0 = SC4 is turned off.
SC3_EN 2 This enable acts upon the LED3.
1 = SC3 is turned on.
0 = SC3 is turned off.
SC2_EN 1 This enable acts upon the LED2.
1 = SC2 is turned on.
0 = SC2 is turned off.
SC1_EN 0 This enable acts upon the LED1.
1 = SC1 is turned on.
0 = SC1 is turned off.
Independent Sink Current Time (ISCT1)—Register 0x11
Table 43. ISCT1 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
SCON SC7OFF SC6OFF SC5OFF
Table 44. Bit Descriptions for the ISCT1 Register
Bit Name Bit No. Description1, 2
SCON 7:6 SC on time. If the SCxOFF time is not disabled, then when the independent current sink is enabled (Register 0x10) it
remains on for the on time selected (per the following list) and then turns off.
00 = 0.2 sec.
01 = 0.6 sec.
10 = 0.8 sec.
11 = 1.2 sec.
SC7OFF 5:4 SC7 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, the ISC turns off for the off time (per the following listed times) and then turns on according to the SCON
setting.
00 = off time disabled.
01 = 0.6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
SC6OFF 3:2 SC6 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, the ISC turns off for the off time (per the following listed times) and then turns on according to the SCON
setting.
00 = off time disabled.
01 = 0.6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
SC5OFF 1:0 SC5 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, the ISC turns off for the off time (per the following listed times) and then turns on according to the SCON
setting.
00 = off time disabled.
01 = 0.6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
1 An independent sink remains on continuously when SCx_EN = 1 and SCx_OFF is 00 (disabled).
2 To enable multiple independent sinks, set the appropriate SCx_EN bits. To create equivalent blinking and fading sequences, enable all independent sinks in one write
cycle to cause a preprogrammed sequence to start simultaneously.
ADP8860
Rev. 0 | Page 39 of 52
Independent Sink Current Time (ISCT2)—Register 0x12
Table 45. ISCT2 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
SC4OFF SC3OFF SC2OFF SC1OFF
Table 46. Bit Descriptions for the ISCT2 Register
Designation Bit Description1, 2
SC4OFF 7:6 SC4 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, then the ISC turns off for the off time (per the following listed times) and then turns on according to
the SCON setting.
00 = off time disabled.
01 = 0. 6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
SC3OFF 5:4 SC3 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, then the ISC turns off for the off time (per the following listed times) and then turns on according to
the SCON setting.
00 = off time disabled.
01 = 0. 6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
SC2OFF 3:2 SC2 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, then the ISC turns off for the off time (per the following listed times) and then turns on according to
the SCON setting.
00 = off time disabled.
01 = 0. 6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
SC1OFF 1:0 SC1 off time. When the SC off time is disabled, the ISC remains on while enabled. When the SC off time is set to any
other value, then the ISC turns off for the off time (per the following listed times) and then turns on according to
the SCON setting.
00 = off time disabled.
01 = 0. 6 sec.
10 = 1.2 sec.
11 = 1.8 sec.
1 An independent sink remains on continuously when SCx_EN = 1 and SCx_OFF is 00 (disabled).
2 To enable multiple independent sinks, set the appropriate SCx_EN bits. To create equivalent blinking and fading sequences, enable all independent sinks in one write
cycle. This causes a preprogrammed sequence to start simultaneously.
ADP8860
Rev. 0 | Page 40 of 52
Independent Sink Current Fade (ISCF)—Register 0x13
Table 47. ISCF Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
SCFO SCFI
Table 48. Bit Descriptions for the ISCF Register
Bit Name Bit No. Description
SCFO 7:4 Sink current fade out rate. The following times listed are for a full-scale fade out (30 mA to 0 mA). Fades between
closer current values reduce the fade time. See the Automated Fade In and Fade Out section for more information.
0000 = disabled.
0001 = 0.30 sec.
0010 = 0.60 sec.
0011 = 0.90 sec.
0100 = 1.2 sec.
0101 = 1.5 sec.
0110 = 1.8 sec.
0111 = 2.1 sec.
1000 = 2.4 sec.
1001 = 2.7 sec.
1010 = 3.0 sec.
1011 = 3.5 sec.
1100 = 4.0 sec.
1101 = 4.5 sec.
1110 = 5.0 sec.
1111 = 5.5 sec.
SCFI 3:0 Sink current fade in rate. The following times listed are for a full-scale fade in (0 mA to 30 mA). Fades between closer
current values reduce the fade time. See the Automated Fade In and Fade Out section for more information.
0000 = disabled.
0001 = 0.30 sec.
0010 = 0.60 sec.
0011 = 0.90 sec.
0100 = 1.2 sec.
0101 = 1.5 sec.
0110 = 1.8 sec.
0111 = 2.1 sec.
1000 = 2.4 sec.
1001 = 2.7 sec.
1010 = 3.0 sec.
1011 = 3.5 sec.
1100 = 4.0 sec.
1101 = 4.5 sec.
1110 = 5.0 sec.
1111 = 5.5 sec.
ADP8860
Rev. 0 | Page 41 of 52
Sink Current Register LED7 (ISC7)—Register 0x14
Table 49. ISC7 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
SCR SCD7
Table 50. Bit Descriptions for the ISC7 Register
Bit Name Bit No. Description
SCR 7 1 = Sink Current 1.
0 = Sink Current 0. For the lowest input current consumption and optimal efficiency, set SCR to 0 when D7 is set
to ISC in Register 0x05 and SC7_EN = 0.
SCD7 6:0 For Sink Current 0, use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
For Sink Current 1, use the following DAC code schedule (see Table 51 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.472 0.004
0000010 0.945 0.014
0000011 01.417 0.034
… … …
1111111 60 60
Table 51. Linear and Square Law Currents for LED7 (SCR = 1)
DAC Code Linear Law (mA) Square Law1 (mA)
0x00 0.000 0
0x01 0.472 0.004
0x02 0.945 0.014
0x03 1.42 0.034
0x04 1.89 0.06
0x05 2.36 0.094
0x06 2.83 0.134
0x07 3.31 0.182
0x08 3.78 0.238
0x09 4.25 0.302
0x0A 4.72 0.372
0x0B 5.20 0.45
0x0C 5.67 0.536
0x0D 6.14 0.628
0x0E 6.61 0.73
0x0F 7.09 0.838
0x10 7.56 0.952
0x11 8.03 1.076
0x12 8.50 1.206
0x13 8.98 1.342
DAC Code Linear Law (mA) Square Law1 (mA)
0x14 9.45 1.488
0x15 9.92 1.64
0x16 10.39 1.8
0x17 10.87 1.968
0x18 11.34 2.142
0x19 11.81 2.326
0x1A 12.28 2.514
0x1B 12.76 2.712
0x1C 13.23 2.916
0x1D 13.70 3.128
0x1E 14.17 3.348
0x1F 14.65 3.574
0x20 15.12 3.81
0x21 15.59 4.052
0x22 16.06 4.3
0x23 16.54 4.558
0x24 17.01 4.822
0x25 17.48 5.092
0x26 17.95 5.372
0x27 18.43 5.658
ADP8860
Rev. 0 | Page 42 of 52
DAC Code Linear Law (mA) Square Law1 (mA)
0x28 18.90 5.952
0x29 19.37 6.254
0x2A 19.84 6.562
0x2B 20.31 6.878
0x2C 20.79 7.202
0x2D 21.26 7.534
0x2E 21.73 7.872
0x2F 22.20 8.218
0x30 22.68 8.57
0x31 23.15 8.932
0x32 23.62 9.3
0x33 24.09 9.676
0x34 24.57 10.058
0x35 25.04 10.45
0x36 25.51 10.848
0x37 25.98 11.254
0x38 26.46 11.666
0x39 26.93 12.086
0x3A 27.40 12.514
0x3B 27.87 12.95
0x3C 28.35 13.392
0x3D 28.82 13.842
0x3E 29.29 14.3
0x3F 29.76 14.764
0x40 30.24 15.238
0x41 30.71 15.718
0x42 31.18 16.204
0x43 31.65 16.7
0x44 32.13 17.202
0x45 32.60 17.71
0x46 33.07 18.228
0x47 33.54 18.752
0x48 34.02 19.284
0x49 34.49 19.824
0x4A 34.96 20.37
0x4B 35.43 20.926
0x4C 35.91 21.486
0x4D 36.38 22.056
0x4E 36.85 22.632
0x4F 37.32 23.216
0x50 37.80 23.808
0x51 38.27 24.406
0x52 38.74 25.014
0x53 39.21 25.628
DAC Code Linear Law (mA) Square Law1 (mA)
0x54 39.69 26.248
0x55 40.16 26.878
0x56 40.63 27.514
0x57 41.10 28.156
0x58 41.57 28.808
0x59 42.05 29.466
0x5A 42.52 30.132
0x5B 42.99 30.806
0x5C 43.46 31.486
0x5D 43.94 32.174
0x5E 44.41 32.87
0x5F 44.88 33.574
0x60 45.35 34.284
0x61 45.83 35.002
0x62 46.30 35.726
0x63 46.77 36.46
0x64 47.24 37.2
0x65 47.72 37.948
0x66 48.19 38.702
0x67 48.66 39.466
0x68 49.13 40.236
0x69 49.61 41.014
0x6A 50.08 41.798
0x6B 50.55 42.59
0x6C 51.02 43.39
0x6D 51.50 44.198
0x6E 51.97 45.012
0x6F 52.44 45.834
0x70 52.91 46.664
0x71 53.39 47.5
0x72 53.86 48.346
0x73 54.33 49.198
0x74 54.80 50.056
0x75 55.28 50.924
0x76 55.75 51.798
0x77 56.22 52.68
0x78 56.69 53.568
0x79 57.17 54.464
0x7A 57.64 55.368
0x7B 58.11 56.28
0x7C 58.58 57.198
0x7D 59.06 58.126
0x7E 59.53 59.058
0x7F 60 60
1 Cubic 10 and Cubic 11 laws use the square law DAC setting but vary the time
step per DAC code (see Figure 31).
ADP8860
Rev. 0 | Page 43 of 52
Sink Current Register LED6 (ISC6)—Register 0x15
Table 52. ISC6 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SCD6
Table 53. Bit Descriptions for the ISC6 Register
Bit Name Bit No. Description
N/A 7 Reserved.
SCD6 6:0 Sink current. Use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
Sink Current Register LED5 (ISC5)—Register 0x16
Table 54. ISC5 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SCD5
Table 55. Bit Descriptions for the ISC5 Register
Bit Name Bit No. Description
N/A 7 Reserved.
SCD5 6:0 Sink current. Use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
Sink Current Register LED4 (ISC4)—Register 0x17
Table 56. ISC4 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SCD4
Table 57. Bit Descriptions for the ISC4 Register
Bit Name Bit No. Description
N/A 7 Reserved.
SCD4 6:0 Sink current. Use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
ADP8860
Rev. 0 | Page 44 of 52
Sink Current Register LED3 (ISC3)—Register 0x18
Table 58. ISC3 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SCD3
Table 59. Bit Descriptions for the ISC3 Register
Bit Name Bit No. Description
N/A 7 Reserved.
SCD3 6:0 Sink current. Use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
Sink Current Register LED2 (ISC2)—Register 0x19
Table 60. ISC2 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SCD2
Table 61. Bit Descriptions for the ISC2 Register
Bit Name Bit No. Description
N/A 7 Reserved.
SCD2 6:0 Sink current. Use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
Sink Current Register LED1 (ISC1)—Register 0x1A
Table 62. ISC1 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved SCD1
Table 63. Bit Descriptions for the ISC1 Register
Bit Name Bit No. Description
N/A 7 Reserved
SCD1 6:0 Sink current. Use the following DAC code schedule (see Table 28 for a complete list of values):
DAC Linear Law (mA) Square Law (mA)
0000000 0 0
0000001 0.236 0.002
0000010 0.472 0.007
0000011 0.709 0.017
… … …
1111111 30 30
ADP8860
Rev. 0 | Page 45 of 52
COMPARATOR REGISTER DESCRIPTIONS
Comparator Configuration (CCFG)—Register 0x1B
Table 64. CCFG Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
FILT FORCE_RD L3_OUT L2_OUT L3_EN L2_EN
Table 65. Bit Descriptions for the CCFG Register
Bit Name Bit No. Description
FILT 7:5 Filter setting for the CMP_IN light sensor.
000 = 80 ms.
001 = 160 ms.
010 = 320 ms.
011 = 640 ms.
100 = 1280 ms.
101 = 2560 ms.
110 = 5120 ms.
111= 10,240 ms.
FORCE_RD 4 Force a read of the CMP_IN light sensor while independent sinks are running, but the backlight is not. Reset by chip
after the conversion is complete and L2_OUT and L3_OUT are valid. Ignored if the backlight is enabled.
L3_OUT 3 This bit is the output of the L3 comparator.
L2_OUT 2 This bit is the output of the L2 comparator.
L3_EN 1 1 = the L3 comparator is enabled for the CMP_IN comparator.
0 = the L3 comparator is disabled for the CMP_IN comparator.
L2_EN 0 Note that the L3 comparator has priority over L2.
1 = the L2 comparator is enabled for the CMP_IN comparator.
0 = the L2 comparator is disabled for the CMP_IN comparator.
Second Comparator Configuration (CCFG2)—Register 0x1C
Table 66. CCFG2 Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
FILT2 FORCE_RD2 L3_OUT2 L2_OUT2 L3_EN2 L2_EN2
Table 67. Bit Descriptions for the CCFG2 Register
Bit Name Bit No. Description
FILT2 7:5 Filter setting for the CMP_IN2 light sensor.
000 = 80 ms.
001 = 160 ms.
010 = 320 ms.
011 = 640 ms.
100 = 1280 ms.
101 = 2560 ms.
110 = 5120 ms.
111= 10,240 ms.
FORCE_RD2 4 Force a read of the CMP_IN2 light sensor while independent sinks are running, but the backlight is not. Reset by
chip after the conversion is complete and L2_OUT and L3_OUT are valid. Ignored if the backlight is enabled.
L3_OUT2 3 This bit is the output of the L3 comparator for the second light sensor.
L2_OUT2 2 This bit is the output of the L2 comparator for the second light sensor.
L3_EN2 1 1 = the L3 comparator is enabled for the CMP_IN2 comparator.
0 = the L3 comparator is disabled for the CMP_IN2 comparator.
ADP8860
Rev. 0 | Page 46 of 52
Bit Name Bit No. Description
L2_EN2 0 Note that the L3 comparator has priority over L2.
1 = the L2 comparator is enabled for the CMP_IN2 comparator.
0 = the L2 comparator is disabled for the CMP_IN2 comparator.
Comparator Level 2 Threshold (L2_TRP)—Register 0x1D
Table 68. L2_TRP Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
L2_TRP
Table 69. Bit Descriptions for the L2_TRP Register
Bit Name Bit No. Description
L2_TRP 7:0 Comparator Level 2 threshold. If the comparator input is below L2_TRP, then the comparator trips and
the backlight enters Level 2 (office) mode. The following lists the code settings for photosensor current:
00000000 = 0 μA.
00000001 = 4.3 μA.
00000010 = 8.6 μA.
00000011 = 12.9 μA.
…
11111010 = 1080 μA.
…
11111111 = 1106 μA.
Although codes above 1111010 (250) are possible, they should not be used. Furthermore, the maximum
value of L2_TRP + L2_HYS must not exceed 1111010 (250).
Comparator Level 2 Hysteresis (L2_HYS)—Register 0x1E
Table 70. L2_HYS Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
L2_HYS
Table 71. Bit Descriptions for the L2_HYS Register
Bit Name Bit No. Description
L2_HYS 7:0 Comparator Level 2 hysteresis. If the comparator input is above L2_TRP + L2_HYS, the comparator trips
and the backlight enters Level 1 (daylight) mode. The following lists the code settings for photosensor
current hysteresis:
0000000 = 0 μA.
00000001 = 4.3 μA.
00000010 = 8.6 μA.
00000011 = 12.9 μA.
…
11111010 = 1080 μA.
…
11111111 = 1106 μA.
Although codes above 1111010 (250) are possible, they should not be used. Furthermore, the maximum
value of L2_TRP + L2_HYS must not exceed 1111010 (250).
ADP8860
Rev. 0 | Page 47 of 52
Comparator Level 3 Threshold (L3_TRP)—Register 0x1F
Table 72. L3_TRP Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
L3_TRP
Table 73. Bit Descriptions for the L3_TRP Register
Bit Name Bit No. Description
L3_TRP 7:0 Comparator Level 3 threshold. If the comparator input is below L3_TRP, the comparator trips and the
backlight enters Level 3 (dark) mode. The following lists the code settings for photosensor current:
0000000 = 0 μA.
0000001 = 0.54 μA.
0000010 = 1.08 μA.
0000011 = 1.62 μA.
…
1111111 = 137.7 μA.
Comparator Level 3 Hysteresis (L3_HYS)—Register 0x20
Table 74. L3_HYS Comparator Level 3 Hysteresis Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
L3_HYS
Table 75. Bit Descriptions for the L3_HYS Register
Bit Name Bit No. Description
L3_HYS 7:0 Comparator Level 3 hysteresis. If the comparator input is above L3_TRP + L3_HYS, the comparator trips
and the backlight enters Level 2 (office) mode. The following lists the code settings for photosensor
current hysteresis:
0000000 = 0 μA.
0000001 = 0.54 μA.
0000010 = 1.08 μA.
0000011 = 1.62 μA.
…
1111111 = 137.7 μA.
First Phototransistor Register: Low Byte (PH1LEVL)—Register 0x21
Table 76. PH1LEVL Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
PH1LEV_LOW
Table 77. Bit Descriptions for the PH1LEVL Register
Bit Name Bit No. Description
PH1LEV_LOW 7:0 13-bit conversion value for the first light sensor—low byte (Bit 7 to Bit 0). The value is updated every
80 ms (when the light sensor is enabled). This is a read-only register.
ADP8860
Rev. 0 | Page 48 of 52
First Phototransistor Register: High Byte (PH1LEVH)—Register 0x22
Table 78. PH1LEVH Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved PH1LEV_HIGH
Table 79. Bit Descriptions for the PH1LEVH Register
Bit Name Bit No. Description
N/A 7:5 Reserved.
PH1LEV_HIGH 4:0 13-bit conversion value for the first light sensor—high byte (Bit 12 to Bit 8). The value is updated every
80 ms (when the light sensor is enabled). This is a read-only register.
Second Phototransistor Register: Low Byte (PH2LEVL)—Register 0x23
Table 80. PH2LEVL Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
PH2LEV_LOW
Table 81. Bit Descriptions for the PH2LEVL Register
Bit Name Bit No. Description
PH2LEV_LOW 7:0 13-bit conversion value for the second light sensor—low byte (Bit 7 to Bit 0) The value is updated every 80 ms
(when the light sensor is enabled). This is a read-only register.
Second Phototransistor Register: High Byte (PH2LEVH)—Register 0x24
Table 82. PH2LEVH Bit Map
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reserved PH2LEV_HIGH
Table 83. Bit Descriptions for the PH2LEVH Register
Bit Name Bit No. Description
N/A 7:5 Reserved.
PH2LEV_HIGH 4:0 13-bit conversion value for the second light sensor—high byte (Bit 12 to Bit 8). The value is updated every
80 ms (when the light sensor is enabled). This is a read-only register.
ADP8860
Rev. 0 | Page 49 of 52
OUTLINE DIMENSIONS
0.645
0.600
0.555
1.995
1.955
1.915
A
B
C
D
E
1
2
3
4
BOTTOM VIEW
(BALL SIDE UP)
TOP VIEW
(BALL SIDE DOWN)
0.287
0.267
0.247
1.60
REF
SEATING
PLANE
0.40
REF
0.415
0.400
0.385 0.230
0.200
0.170
0.05 MAX
COPLANARITY
2.395
2.355
2.315
BALL A1
IDENTIFIER
021009-A
Figure 47. 20-Ball Wafer Level Chip Scale Package [WLCSP]
(CB-20-6)
Dimensions shown in millimeters
2.65
2.50 SQ
2.35
3.75
BSC SQ
4.00
BSC SQ
1
0.50
BSC
PIN 1
INDICATOR
0.50
0.40
0.30
COMPLIANT
TO
JEDEC STANDARDS MO-220-VGGD-1
090408-B
TOP VIEW
12° MAX 0.80 MAX
0.65 TYP
SEATING
PLANE
PIN 1
INDI
C
ATOR
COPLANARITY
0.08
1.00
0.85
0.80
0.30
0.23
0.18
0.05 MAX
0.02 NOM
0.20 REF
20
6
16
10
11
15
5
EXPOSED
PAD
(BOTTOM VIEW)
0.60 MAX
0.60 MAX
0.25 MIN
FOR PROPER CONNECTION OF
THE EXPOSED PAD, REFER TO
THE PIN CONFIGURATION AND
FUNCTION DESCRIPTIONS
SECTION OF THIS DATA SHEET.
Figure 48. 20-Lead Lead Frame Chip Scale Package [LFCSP_VQ]
4 mm × 4 mm Body, Very Thin Quad
(CP-20-4)
Dimensions shown in millimeters
ADP8860
Rev. 0 | Page 50 of 52
ORDERING GUIDE
Model Temperature Range Package Description Package Option
ADP8860ACBZ-R71−40°C to +85°C 20-Ball WLCSP, Tape and Reel CB-20-6
ADP8860ACPZ-R71
−40°C to +85°C 20-Lead LFCSP_VQ, Tape and Reel CP-20-4
1 Z = RoHS Compliant Part.
07967-033
07967-034
Figure 49. Tape and Reel Orientation for WLCSP Units
Figure 50. Tape and Reel Orientation for LFCSP Units
ADP8860
Rev. 0 | Page 51 of 52
NOTES
ADP8860
Rev. 0 | Page 52 of 52
NOTES
©2009 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D07967-0-5/09(0)
