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Datasheet: AS1109 8-Bit LED Driver with Diagnostics
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AS1109
Constant-Current, 8-Bit LED Driver with Diagnostics
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 1 - 24
1 General Description
The AS1109 is designed to drive up to 8 LEDs through a fast serial
interface and features 8 output constant current drivers and an on-
chip diagnostic read-back function.
The high clock-frequency (up to 50MHz), adjustable output current,
and flexible serial interface makes the device perfectly suited for
high-volume transmission applications.
Output current is adjustable (up to 100mA/channel) using an external
resistor (REXT).
The serial interface with Schmitt trigger inputs includes an integrated
shift register. Additionally, an internal data register stores the
currently displayed data.
The device features integrated diagnostics for over-
temperature, open-LED, and shorted-LED conditions. Integrated
registers store global fault status information during load as well as
the detailed temperature/open-LED/shorted-LED diagnostics results.
The AS1 109 also features a low-current diagnostic mode to minimize
display flicker during fault testing.
With an operating temperature range from -40 to +125°C the
AS1109 is also ideal for industrial applications.
The AS1109 is available in a 16-pin SOIC-150, a 16-pin QFN
(4x4mm) and the 16-pin QSOP-150 package.
Figure 1. Main Diagram and Pin Assignments
2 Key Features
8 Constant-Current Output Channels
Excellent Output Current Accuracy
- Between Channels: ±2%
- Between AS1109 Devices: ±2%
Output Current Per Channel: 0.5 to 100mA
Controlled In-Rush Current
Over-Temperature, Open-LED, Shorted-LED
Diagnostics Functions
Low-Current Test Mode
Global Fault Monitori ng
Low Shutdown Mode Current: 3µA
Fast Serial Interface: up to 50MHz
Cascaded Configuration
Fast Output Drivers Suitab le for PWM
16-pin SOIC-150, 16-pin QFN (4x4mm) and 16-pin QSOP-150
Package
3 Applications
The device is ideal for fixed- or slow-rolling displays using static or
multiplexed LED matrix and dimming functions, large LED matrix
displays, mixed LED display and switch monitoring, displays in
elevators, public transports (underground, trains, buses, taxis,
airplanes, etc.), large displays in stadiums and public areas, price
indicators in retail stores, promotional panels, bar-graph displays,
industrial controller displays, white good panels, emergency light
indicators, and traffic signs.
AS1109
SDI SDO
CLK LD OEN REXT
+VLED
1
GND
AS1109
16 VDD
2
SDI
3
CLK
4
LD
5
OUTN0
15 REXT
14 SDO
13 OEN
9OUTN4
8
OUTN3
7
OUTN2
6
OUTN1
12 OUTN7
11 OUTN6
10 OUTN5
OUTN0 OUTN1 OUTN2 OUTN3 OUTN4 OUTN5 OUTN6 OUTN7
GND VDD
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 2 - 24
AS1109
Datasheet
4 Pin Assignments
Figure 2. Pin Assignments (Top View)
4.1 Pin Descriptions
Table 1. Pin Descriptions
Pin Number Pin Name Description
16-pin QSOP-150
16-pin SOIC-150 16-pin QFN
(4x4mm)
115GND
Ground
216SDI
Serial Data Input
31CLK
Serial Data Clock. The rising edge of the CLK signal is used to clock data into and at
the falling edge out of the AS1 109 shift register . In error mode, the rising edge of the CLK
signal is used to switch error modes.
42LD
Serial Data Load. Data is transferred to the data register at the rising edge of this pin.
5:12 3:10 OUTN0:7 Output Current Drivers. These pins are used as LED drivers or for input sense for
diagnostic modes.
13 11 OEN
Output Enable. The active-low pin OEN signal can always enable output drivers to sink
current independent of the AS1109 mode.
0 = Output drivers are enabled.
1 = Output drivers are disabled.
14 12 SDO
Serial Data Output. In normal mode SDO is clocked out 8.5 clock cycles after SDI is
clocked in.
In global error detection mode this pin indicates the occurrence of a global error.
0 = Global error mode returned an error.
1 = No errors.
15 13 REXT External Resistor Connection. This pin connects through the external resistor (REXT)
to GND, to setup the load current.
16 14 VDD Positive Supply Voltage
1
GND
AS1109
16 VDD
2
SDI
3
CLK
4
LD
5
OUTN0
15 REXT
14 SDO
13 OEN
9OUTN4
8
OUTN3
7
OUTN2
6
OUTN1
12 OUTN7
11 OUTN6
10 OUTN5
SDO
OUTN2
GND VDD REXT
13
6
12
OUTN7
10
5
1415
CLK 1
LD 2
OUTN1 4
AS1109
16-pin QFN
(4x4mm)
OUTN0 3
7 8
OUTN6
9
OEN
11
SDI
16
OUTN3
OUTN4
OUTN5
16-pin QSOP-150
16-pin SOIC-150
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 3 - 24
AS1109
Datashee t - A b s o l u t e M a x i mu m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of
the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect device reliability.
Table 2. Absolute Maximum Ratings
Parameter Min Max Units Comments
Electrical Parameters
VDD to GND -0.3 7 V
Input Voltage -0.4 VDD + 0.4 V
Output Voltage -0.4 15 V
GND Pin Current 1000 m A
Input Current (latch-up immunity) -100 100 mA Norm: JEDEC 78
Electrostatic Discharge
Electrostatic Discharge HBM 2 kV Norm: MIL 883 E method 3015
Temperature Ranges and Storage Conditions
Thermal Resistance ΘJA
33 ºC/W on PCB, 16-pin SOIC-150 package
113 ºC/W on PCB, 16-pin QSOP-150 package
32 ºC/W on PCB, 16-pin QFN (4x4mm) package
Storage Temperature Range -55 +150 ºC
Package Body Temperature +260 ºC
The reflow peak soldering temperature (body
temperature) specified is in accordance with IPC/
JEDEC J-STD-020“Moisture/Reflow Sensitivity
Classification for Non-Hermetic Solid State Surface
Mount Devices”.
The lead finish for Pb-free leaded packages is matte tin
(100% Sn).
Humidity non-condensing 5 85 %
Moisture Sensit iv e Level QFN and QSOP 1 Represents a maximum floor life time of unlimited
Moisture Sensitive
Layer (SOIC) 3 Represents a maximum floor life of 168h
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 4 - 24
AS1109
Datasheet - Electrical Characteristics
6 Electrical Characteristics
VDD = +3.0V to +5.5V, Typical values measured at VDD = 5V, TAMB = 25°C (unless otherwise specified).
Table 3. Electrical Characteristics
Symbol Parameter Condition Min Typ Max Unit
TAMB Operating Temperature Range Device fully functional up to 125°C -40 +85 °C
VDD Supply Voltage 3.0 5.5 V
VDS Output Voltage OUTN0:7 0 15.0 V
IOUT
Output Current
OUTN0:7, VDD = 5V (see Figure 8) 0.5 100
mA
IOH SDO -1.0
IOL SDO 1.0
VIH Input Voltage High Level CLK, OEN, LD, SDI
0.7 x
VDD VDD +
0.3 V
VIL Low Level -0.3 0.3 x
VDD
IDS(OFF) Output Leakage Current OEN = 1, VDS = 15.0V 0.5 µA
VOL Output
Voltage SDO IOL = +1.0mA 0.4 V
VOH IOH = -1.0mA VDD -
0.4V
IAV(LC1) Device-to-Device Average Output Current
from OUTN0 to OUTN7 VDS = 0.5V, VDD = Const.,
REXT = 744Ω24.5 25.26 26 mA
ΔIAV(LC1) Current Skew
(Between Channels) VDS ≥ 0.5V, VDD = Const.,
REXT = 744Ω ±0.9 ±3 %
IAV(LC2) Device-to-Device Average Output Current
from OUTN0 to OUTN7 VDS = 0.6V, VDD > 3.3V,
REXT = 372Ω49.50 50.52 51.55 mA
ΔIAV(LC2) Current Skew
(Between Channels) VDS ≥ 0.6V, VDD = Const.,
REXT = 372Ω ±0.8 ±2 %
IAV(LC3) Device-to-Device Average Output Current
from OUTN0 to OUTN7 VDS = 0.8V, VDD = 5.0V,
REXT = 186Ω 98 101 104 mA
ΔIAV(LC3) Current Skew
(Between Channels) VDS ≥ 0.8V, VDD = Const.,
REXT = 186Ω±0.5 ±2 %
ILC Low-Current Diagnosis Mode VDS = 0.8V, VDD = 5.0V 0.4 0.6 0.8 mA
IPD Power Down Supply Current VDS = 0.8V, VDD = 5.0V,
REXT = 372Ω, OUTN0:7 = On 320µA
%/ΔVDS Output Current vs.
Output Voltage Regulation VDS within 1.0 and 3.0V ±0.1 %/V
%/ΔVDD Output Current vs.
Supply Voltage Regulation VDD within 3.0 and 5.0V ±1 %/V
RIN(UP) Pullup Resistance OEN 250 500 800 kΩ
RIN(DOWN) Pulldown Resistance LD 250 500 800 kΩ
VTHL* Open Error Detection Threshold Voltage No load 0.25 0.35 0.45 V
VTHH* Short Error Detection Threshold Voltage VDD = 3.0V, no load 1.2 1.3 1.4 V
VDD = 5.0V, no load 2.0 2.2 2.4
TOV1 Overtemperature Threshold Flag 150 ºC
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 5 - 24
AS1109
Datasheet - Electrical Characteristics
6.1 Switching Characteristics
VDD = 3.0 to 5.5V, VDS = 0.8V, VIH = VDD, VIL = GND, REXT = 372Ω, VLOAD = 4.0V, RLOAD = 64Ω, CLOAD = 10pF; guaranteed by design.
* If multiple AS1109 devices are cascaded and tr or tf is large, it may be critical to achieve the timing required for data transfer between two
cascaded LED drivers.
Note: All limits are guaranteed. The parameters with min and max values are guaranteed with production tests or SQC (Statistical Quality
Control) methods.
IDD(OFF)0
Supply Current
Off
REXT = Open‚ OUTN0:7 = Off 1.3 2
mA
IDD(OFF)1 REXT = 744Ω‚ OUTN0:7 = Off 3.0 3.68
IDD(OFF)2 REXT = 372Ω‚ OUTN0:7 = Off 4.7 5.37
IDD(OFF)3 REXT = 186Ω, OUTN0:7 = Off 8.1 8.73
IDD(ON)1
On
REXT = 744Ω‚ OUTN0:7 = On 4.5 5
IDD(ON)2 REXT = 372Ω‚ OUTN0:7 = On 7.5 8
IDD(ON)3 REXT = 186Ω‚ OUTN0:7 = On 13.7 15
Table 4. Switching Characteristics
Symbol Parameter Conditions Min Typ Max Unit
tP1 Propagation Delay T i me CLK - SDO 5 10 nstP2 Propagation Delay Time (Without Staggered
Output Delay) LD - OUTNn 100 200
tP3 OEN - OUTNn 100 200
tP4 Propagation Delay Time 10 ns
tW(CLK) Pulse Width CLK 15 nstW(L) LD 15
tW(OE) OEN (@IOUT < 60mA) 200
tR *Maximum CLK Rise Time 500 ns
tF *Maximum CLK Fall Time 500 ns
tOR Output Rise Time of VOUT (Turn Off) 100 200 ns
tOF Output Fall Time of VOUT (Turn On) 100 300 ns
tSU(D) Setup Time for SDI 5 ns
tH(D) Hold Time for SDI 5 ns
tSU(L) Setup Time for LD 5 ns
tH(L) Hold Time for LD 5 ns
tTESTING Minimum OEN Time for Error Detection 2000 ns
tSTAG Staggered Output Delay 20 40 ns
tSU(OE) Output Enable Setup Time 20 ns
tGSW(ERROR) Global Error Switching Setup Time 10 ns
tSU(ERROR) Global Error Detection Setup Time 10 ns
tP(I/O) Propagation Delay Global Error Flag 5 ns
tSW(ERROR) Switching Time Global Error Flag 10 ns
fCLK Maximum Clock Frequency
(Cascade Operation) 30 50 MHz
tP3,ON Low-Current Test Mode
Propagation Delay Time Turn ON 3 5 µs
tTP3,OFF Turn OFF 0.05 0.1 µs
tREXT2,1 External Resistor Reaction Time Change from REXT1 = 372Ω, IOUT1
= 50.52mA to REXT2 = 37.2kΩ,
IOUT2 < 1mA
0.5 1 µs
tREXT2,1 External Resistor Reaction Time Change from REXT1 = 37.2kΩ,
IOUT1 = 0.5mA to REXT2 = 372Ω,
IOUT2 > 25mA
0.5 1 µs
Table 3. Electrical Characteristics (Continued)
Symbol Parameter Condition Min Typ Max Unit
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 6 - 24
AS1109
Datasheet - Typical Operating Characteristics
7 Typical Operating Characteristics
Figure 3. Output Current vs. REXT, Figure 4. Relative Output Current Error vs. VDD,
VDD = 5V; VOUT = 0.8V, TAMB = 25°C Iout/Iout@VDD = 5V - 1, TAMB = 25°C
Figure 5. Output Current vs. VDS; Figure 6. Output Current vs. VDS;
VDD = 5V, TAMB = 25°C VDD = 5V, TAMB = 25°C
Figure 7. Relative IOUT Error vs. Temperature Figure 8. Output Current vs. VDD
VDD = 5V, Iout/Iout@25°C - 1, TAMB = 25°C
1
10
100
100 1000 10000
REXT (Ohm)
IOUT (mA) .
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
33.544.555.5
VDD (V)
Relat iv e Out put Cur r ent Er r or (%)
.
REXT = 744Ω;
VDS = 0.5V
REXT = 372Ω;
VDS = 0.6V
REXT = 186Ω;
VDS = 0.8V
0
20
40
60
80
100
120
140
160
02468101214
VDS (V)
IOUT (mA) .
REXT = 127Ω
REXT = 251Ω
REXT = 372Ω
REXT = 150Ω
REXT = 186Ω
REXT = 744Ω
0
20
40
60
80
100
120
140
160
0 0.2 0.4 0.6 0.8 1 1.2 1.4
VDS (V)
IOUT (mA) .
REXT = 127Ω
REXT = 251Ω
REXT = 372Ω
REXT = 150Ω
REXT = 186Ω
REXT = 744Ω
-1
-0.5
0
0.5
1
-50-250255075100
Temperature ( °C)
Relat iv e Out put Cur r ent Er r or (%)
.
REXT = 372Ω;
VDS = 0.6V
REXT = 744Ω;
VDS = 0.5V
REXT = 186Ω;
VDS = 0.8V
0
20
40
60
80
100
120
140
160
3 3.5 4 4.5 5 5.5
VDD (V)
IOUT (mA) .
VDS = 1V
VDS = 0.9V
VDS = 0.8V
VDS = 0.7V
VDS = 0.6V
VDS = 0.5V
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 7 - 24
AS1109
Datasheet - Detailed Description
8 Detailed Description
The AS1109 is designed to drive up to 8 LEDs through a fast serial interface and 8 constant-current output drivers. Furthermore, the AS1109
provides diagnostics for detecting open- or shorted-LEDs, as well as over-temperature conditions for LED display systems, especially LED traffic
sign application s.
The AS1 109 contains an 8-bit shift register and an 8-bit data register , which convert serial input data into parallel output format. At AS1 109 output
stages, eight regulated current sinks are designed to provide uniform and constant current with excellent matching between ports for driving
LEDs within a wide range of forward voltage variations. External output current is adjustable from 0.5 to 100mA using an external resistor for
flexibility in controlling the brightness intensity of LEDs. The AS1109 guarantees to endure 15V maximum at the outputs.
The serial interface is capable of operating at a minimum of 30 MHz, satisfying the requirements of high-volume data transmission.
Using a multiplexed input/output technique, the AS1109 adds additional functionality to pins SDO, LD and OEN. These pins provide highly useful
functions (open- and shorted-LED detection, over-temperature detection), thus reducing pin count. Over-temperature detection will work on-the-
run, whereas the open- and shorted-LED detection can be used on-the-run or in low-current diagnostic mode (see page 14).
Figure 9. AS1109 - Block Diagram
8.1 Serial Interface
Data accesses are made serially via pins SDI and SDO. At each CLK rising edge, the signal present at pin SDI is shifted into the first bit of the
internal shift register and the other bits are shifted ahead of the first bit. The MSB is the first bit to be clocked in. In error-detection mode the shift
register will latch-in the corresponding error data of temperature-, open-, and short-error register with each falling edge of LD.
AS1109
REXT
OEN
CLK
SDI
LD
Current
Generators
Detailed
Error
Detection
8-Bit Data
Register
8-Bit Shift
Register
Temperature
Detection 8-Bit Open Detec-
tion & Error Reg-
ister
8-Bit Short
Detection & Error
Register
Global Error
Detection
SDO
Indicates 8 Bit Path
Control Logic
+VLED
OUTN0 OUTN1 OUTN2 OUTN3 OUTN4 OUTN5 OUTN6 OUTN7
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 8 - 24
AS1109
Datasheet - Detailed Description
The 8-bit data register will latch the data of the shift register at each rising edge of LD. This data is then used to drive the current generator output
drivers to switch on the corresponding LEDs as OEN goes low.
8.2 Timing Diagrams
This section contains timing diagrams referenced in other sections of this data sheet.
Figure 10. Normal Mode Timing Diagram
Figure 11. Output Delay Timing Diagram
OEN
OUTNx
LD
SDO
SDI
CLK
tSU(L) tH(L)
tW(L)
tW(CLK)
tP1
tH(D)
50% 50% 50%
50% 50%
50%
tSU(D)
OEN Low = Ou tput Enabl e d
tP2
OUTNx High = Output Off
OUTNx Low = Output On
50%
50% 50%
tW(OE)
7XtSTAG
tP3
OEN
OUTN0
OUTN1
OUTN7
50% 50%
50%50%
tOF tOR
tSTAG
90% 90%
10% 10%
7XtSTAG
tSTAG
tP3
50% 50%
50% 50%
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 9 - 24
AS1109
Datasheet - Detailed Description
Figure 12. Data Input Timing Diagram
Figure 13. Data Input Example Timing Diagram
SDI
CLK
OEN
LD
SDO
8 CLK Pulses
tSU(OE)
tW(L)
tSU(L
tW(OE)
tH(D)
tP1
Data Bit
7Data Bit
6Data Bit
5Data Bit
4Data Bit
3Data Bit
2Data Bit
1Data Bit
0
Old Data
Bit 7 Old Data
Bit 6 Old Data
Bit 5 Old Data
Bit 4 Old Data
Bit 3 Old Data
Bit 2 Old Data
Bit 1 Old Data
Bit 0
Don’t Care
Don’t Care
tSU(D)
SDI
OEN
LD
OUTN0
OUTN1
OUTN7
OUTN2
OUTN3
OUTN4
OUTN5
OUTN6
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
Off
On
D6D7 D5 D4 D3 D2 D1 D0
1234567
Time = 0
CLK
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 10 - 24
AS1109
Datasheet - Detailed Description
Figure 14. Switching Global Error Mode Timing Diagram
8.3 Error-Detection Mode
Acquisition of the error status occurs at the rising edge of OEN. Error-detection mode is started on the rising edge of LD when OEN is high. The
CLK signal must be low when entering error detection mode. Error detection for open- and shorted-LEDs can only be performed for LEDs that
are switched on during test time. To switch between error-detection modes clock pulses are needed (see Table 5).
Note: To test all LEDs, a test pattern that turns on all LEDs must be input to the AS1109.
8.4 Global Error Mode
Global error mode is entered when error-detection mode is started. Clock pulses during this period are used to select between temperature,
open-LED, and shorted-LED tests, as well as low-current diagnostic mode and shutdown mode (see Table 5). In global error mode, an error flag
(TFLAG, OFLAG, SFLAG) is delivered to pin SDO if any errors are encountered.
Note: For a valid result SDI must be 1 for the first device.
If there are multiple AS1 109s in a chain, the error flag will be gated through all devices. To get a valid result at the end of the chain, a logic 1 must
be applied to the SDI input of the first device of the chain. If one device produces an error this error will show up after n*tP(I/O) + tSW(ERROR) at
pin SDO of the last device in the chain. This means it is not possible to identify which device in the chain produced the error. Therefore, if a global
error occurs, the detailed error report can be run to identify which AS1109, or LED produced the error.
Note: When no error has occurred, the detailed error report can be skipped, setting LD and subsequently OEN low.
Table 5. Global Error Mode Selections
Clock
Pulses Output Port Error-Detection Mode Global Error Flag/Shutdown Condition
0 Don't Care Over-Tempe rature Detection TFLAG = SDO = 1: No over-temperature warning.
TFLAG = SDO = 0: Over-temperature warning.
1 Enabled Open-LED Detection OFLAG = SDO = 1: No open-LED error.
OFLAG = SDO = 0: Open-LED error.
2 Enabled Shorted-LED Detection SFLAG = SDO = 1: No shorted-LED error.
SFLAG = SDO = 0: Shorted-LED error.
3 Don't Care Low-Current Diagnostic Mode
4 Don't Care Shutdown Mode SDI = 1: Wakeup
SDI = 0: Shutdown
tTESTING
tSU(ERROR)
OFLAG(IN) SFLAG(IN)TFLAG(IN)
TFLAG OFLAG SFLAG
tSW(ERROR)
SDI
OEN
LD
CLK
SDO
Acquisition of Error
Status
Don’t
Care Don’t
Care
tGSW(ERROR)
tP(I/O)
tP4
tP(I/O) tP(I/O)
tSW(ERROR)
tGSW(ERROR)
tGSW(ERROR)
Don’t
Care
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 11 - 24
AS1109
Datasheet - Detailed Description
8.5 Error Detection Functions
8.5.1 Open-LED Detection
The AS1109 open-LED detection is based on the comparison between VDS and VTHL. The open LED status is aquired at the rising edge of
OEN and stored internally. While detecting open-LEDs the output port must be turned on. Open LED detection can be started with 1 clock pulse
during error detection mode while the output port is turned on.
Note: LEDs which are turned off at test time cannot be tested.
8.5.2 Shorted-LED
The AS1109 shorted-LED detection is based on the comparison between VDS and VTHH. The shortened LED status is acquired at the rising
edge of OEN and stored internally. While detecting shorted-LEDs the output port must be turned on. Shorted-LED detection can be started with
2 clock pulses during error detection mode while the output port is turned on.
For valid results, the voltage at OUTN0:OUTN7 must be lower then VTHH under low-current diagnostic mode operating conditions. This can be
achieved by reducing the VLED voltage or by adding additional diodes, resistors or LED’s.
Note: LEDs which are turned off at test time cannot be tested.
8.5.3 Overtemperature
Thermal protection for the AS1109 is provided by continuously monitoring the device’s core temperature. The overtemperature status is aquired
at the rising edge of OEN and stored internally.
Table 6. Open LED Detection Modes
Output Port State Effective Output
Point Conditions Detected Open-LED
Error Status Code Meaning
On VDS < VTHL 0 Open Circuit
On VDS > VTHL 1 Normal
Table 7. Shorted LED Detection Modes
Output Port State Effective Output
Point Conditions Detected Shorted-LED
Error Status Code Meaning
On VDS > VTHH 0 Short Circuit
On VDS < VTHH 1 Normal
Table 8. Overtemperature Modes
Output Port State Effective Output
Point Conditions Detected Overtemperature
Status Code Meaning
Don’t Care Temperature > TOV1 0 Overtemperature Condition
Don’t Care Temperature < TOV1 1Normal
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 12 - 24
AS1109
Datasheet - Detailed Description
8.6 Detailed Error Reports
The detailed error report can be read out after global error mode has been run. On the falling edge of LD, the detailed error report of the selected
test is latched into the shift register and can be clocked out with n*8 clock cycles (n is the number of AS1109s in a chain) via pin SDO. At the
same time new data can be written into the shift register, which will load on the next rising edge of pin LD. This data will show at the output
drivers, at the falling edge of OEN.
8.6.1 Detailed Temperature Warning Report
The detailed temperature warning report can be read out immediately after global error mode has been run. Bit0 of the 8bit data word represents
the temperature flag of the chip.
Figure 15. Detailed Temperature Warning Report Timing Diagram
Detailed Temperature Warning Report Example
Consider a case where five AS1109s are cascaded in one chain. The detailed error report lists the temperatures for each device in the chain:
IC1:[70°] IC2:[85°] IC3:[66°] IC4:[160°] IC5:[76°]
In this case, IC4 is overheated and will generate a global error, and therefore 5*8 clock cycles are needed to write out the detailed temperature
warning report, and optionally read in new data. The detailed temperature warning report would look like this:
XXXXXXX1 XXXXXXX1 XXXXXXX1 XXXXXXX0 XXXXXXX1
The 0 in the detailed temperature warning report indicates that IC4 is the device with the over-temperature condition.
Note: In an actual report there are no spaces in the output.
Global Flag Readout Detailed Error Report Readout
tH(L)
tP4
tP4
SDI
OEN
LD
CLK
SDO
New Data Input
TFLAG
DBit7
Undefined
Don’t
Care
Don’t
Care
Temperature Error Report Output
DBit6 DBit5 DBit4 DBit3 DBit2 DBit1 DBit0
TBit0
t(SU)ERROR
tP1
For detailed timing information see Timing Diagrams on page 8.
tGSW(ERROR)
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 13 - 24
AS1109
Datasheet - Detailed Description
8.6.2 Detailed Open-LED Error Report
The detailed open-LED error report can be read out immediately after global error mode has been run.
Figure 16. Detailed Open-LED Error Report Timing Diagram
Detailed Open-LED Error Report Example
Consider a case where five AS1109s are cascaded in one chain. A 1 indicates a LED is on, a 0 indicates a LED is off, and an X indicates an open
LED. The open-LED test is only applied to LEDs that are turned on. This test is used with a test pattern where all LEDs are on at test time.
IC1:[11111111] IC2:[111XX111] IC3:[11111111] IC4:[1X111111] IC5:[11111111]
IC2 has two open LEDs and IC4 has one open LED switched on due to input. 5*8 clock cycles are needed to write the entire error code out. The
detailed error report would look like this:
Comparing this report with the input data indicates that IC2 is the device with two open LEDs at position 4 and 5 and IC4 with an open LED at
second position. For such a test it is recommended to enter low-current diagnostic mode first (see Low-Current Diagnostic Mode on page 14) to
reduce onscreen flickering.
Note: In an actual report there are no spaces in the output.
LEDs turned off during test time cannot be tested.
Input Data:11111111 11111111 1 1111111 11111111 11111111
LED Status:11111111 111XX111 11111111 1X111111 11111111
Failure Code:11111111 11100111 11111111 10111111 11111111
Acquisition of
Error Status
Global Flag Readout Detailed Error Report Readout
SDI
OEN
LD
CLK
SDO
tH(L)
Open Error Report Output
New Data Input
tP4
tP1
tP4
tSW(ERROR)
tSU(ERROR)
tTESTING
DBit0DBit1DBit2DBit3DBit4DBit5DBit6
OBit0OBit1OBit2OBit3OBit4OBit5OBit6
Don’t
Care
Don’t
Care
OBit7
TFlag OFlag
DBit7
For detailed timing information see Timing Diagrams on page 8.
tGSW(ERROR)
tGSW(ERROR)
tGSW(ERROR)
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 14 - 24
AS1109
Datasheet - Detailed Description
8.6.3 Detailed Shorted-LED Error Report
The detailed shorted-LED error report can be read out immediately after global error mode has been run (see Global Error Mode on page 10).
Figure 17. Deta iled Shorted-LED Error Report Timing Diagram
Detailed Shorted-LED Error Report Example
Consider a case where five AS1109s are cascaded in one chain. A 1 indicates a LED is on, a 0 indicates a LED is off, and an X indicates a
shorted LED. This test is used with a test pattern where all LEDs are on at test time. Additionally, this test should be run after starting low-current
diagnostic mode (see Low-Current Diagnostic Mode on page 14).
IC1:[11111XX1] IC2:[11111111] IC3:[11111111] IC4:[111X1111] IC5:[11111111]
IC2 has two shorted LEDs and IC4 has one shorted LED switched on due to input. 5*8 clock cycles are needed to write the entire error code out.
The detailed error report would look like this:
Showing IC1 as the device with two shorted LEDs at position 6 and 7, and IC4 with one shorted LED at position 4.
Note: In an actual report there are no spaces in the output. LEDs turned off during test time cannot be tested.
8.6.4 Low-Current Diagnostic Mode
To run the open- or shorted-LED test, a test pattern must be used that will turn on each LED to be tested. This test pattern will cause a short
flicker on the screen while the test is being performed. The low-current diagnostic mode can be initiated prior to running a detailed error report to
reduce this on-screen flickering.
Note: Normally, displays using such a diagnosis mode require additional cables, resistors, and other components to reduce the current. The
AS1109 has this current-reduction capability built-in, thereby minimizing the number of external components required.
Low-current diagnostic mode can be initiated via 3 clock pulses during error-detection mode. After the falling edge of LD, a test pattern displaying
all 1s can be written to the shift register which will be used for the next error-detection test.
On the next falling edge of OEN, current is reduced to ILC. With the next rising edge of OEN the current will immediately increase to normal
levels and the detailed error report can be read out entering error-detection mode.
Input Data: 11111111 11111111 11111111 11111111 11111111
LED Status: 11111XX1 11111111 11111111 111X1111 11111111
Failure Code: 11111001 11111111 11111111 11101111 11111111
Global Flag Readout Detailed Error Report Readout
SDI
OEN
LD
CLK
SDO
tH(L)
tSU(ERROR)
tP1
tSW(ERROR)
tP4
TFLAG SFLAG
Acquisition of Error
Status
DBit6 DBit5 DBit4 DBit3 DBit2 DBit1 DBit0 Don’t
Care
Don’t
Care
SBit6 SBit5 SBit4 SBit3 SBit2 SBit1 SBit0SBit7
New Data Input
Shorted-LED Error Report Output
OFLAG
TFLAG
tP4
tTESTING
Global Flag Readout
DBit7
For detailed timing information see Timing Diagrams on page 8.
tGSW(ERROR)
tGSW(ERROR)
tGSW(ERROR)
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 15 - 24
AS1109
Datasheet - Detailed Description
Figure 18. Switching into Low-Current Diagnostic Mode Timing Diagram
8.7 Shutdown Mode
The AS1109 features a shutdown mode which can be entered via 4 clock pulses during error-detection mode. To enable the shutdown mode a 0
must be placed at SDI after the rising edge of the 3rd clock pulse.
To disable shutdown mode a 1 must be placed at SDI after the 3rd clock pulse. The shutdown/wakeup information will be latched through if
multiple AS1109 devices are in a chain. At the rising edge of the 4th clock pulse the shutdown bit will be read out and the AS1109 will shutdown
or wakeup.
Note: In shutdown mode the supply current drops down to typically 3µA.
Figure 19. Shutdown Mode Timing Diagram
OFLAGTFLAG SFLAG Don’t
Care
Re-entering Error Detection
Mode
tTESTING
Global Flag Readout
SDI
OEN
LD
CLK
SDO
Load Internal all 1s T est
Pattern
(optional)
tH(L)
tP4
tSW(ERROR)
tP1
tSU(ERROR)
Normal Operation Current
For detailed timing information see Timing Diagrams on page 8.
tGSW(ERROR)
tGSW(ERROR)
tGSW(ERROR)
2µs Low-Current Diagnosis Mode
tH(L)
SDI
OEN
LD
CLK
SDO
1 = Wakeup
0 = Shutdown
1 = Wakeup
0 = Shutdown
OFLAGTFLAG SFLAG
tP4
tSU(ERROR)
tSU(D)
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 16 - 24
AS1109
Datasheet - Application Information
9 Application Information
9.1 Error Detection
The AS1109 features two types of error detection. The error detection can be used on-the-fly, for active LEDs, without any delay, or by entering
into low-current diagnosis mode.
9.1.1 Error Detection On-The-Fly
Error detection on-the-fly will output the status of active LEDs during operation. Without choosing an error mode this will output the temperature
flag at every input/output cycle. Triggering one clock pulse for open or two clock pulses for short detection during error detection mode outputs
the detailed open- or short-error report with the next input/output cycle (see Figure 20). LEDs that are turned off cannot be tested and their digits
at the error output must be ignored.
Figure 20. Normal Operation with Error Detection During Operation – 128 Cascaded AS1109s
Display
SDI
SDO
CLK
OEN
LD
Current
Data1 Data2 Data3
T/O or S Error Code
Data1
T/O or S Error Code Data0
Data0 T/O or S Error Code
Data2
1024x 1024x 1024x
Clock for Error
Mode 0x/1x/2x
Rising Edge of OEN
Acquisition of Error Status
Falling Edge of LD; Error Register is copied
into Shift Register
≤ 100mA
GEFGEF
GEF = Global Error Flag
Falling Edge of LD; Error Register is copied
into Shift Register
Clock for Error
Mode 0x/1x/2x
Rising Edge of OEN
Acquisition of Error Status
Data2 Data3 Data4
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 17 - 24
AS1109
Datasheet - Application Information
9.1.2 Error Detection with Low-Current Diagnosis Mode
This unique feature of the AS1109 uses an internal all 1s test pattern for a flicker free diagnosis of all LEDs. This error detection mode can be
started anytime, and does not require any SDI input (see Figure 21).
Figure 21. Low-Current Diagnosis Mode with Internal All 1s Test Pattern – 128 Cascaded AS1109s
Low-current diagnosis mode is started with 3 clock pulses during error detection mode. After the three pulses of CLK, a pulse of LD loads the
internal all 1s test pattern. Then OEN should be enabled for 2µs for testing. With the rising edge of OEN the test of the LEDs is stopped and
while LD is high the desired error mode can be selected with the corresponding clock pulses.
With the next data input the detailed error code will be clocked out at SDO.
Note: See Figure 22 for the use of an external test pattern.
Figure 22. Low-Current Diagnosis Mode with External Test Pattern – 128 Cascaded AS1109s
GEF
1024x1024x
Data0 Data1
Rising Edge of OEN
Acquisition of Error Status
Falling Edge of LD; Error Register is cop-
ied into Shift Register
GEF
O or S Error Code of
All 1s Test Patern Temperature Error Code
Load Internal All 1s Test Pattern
≤ 100mA ≤ 100mA
2µs Low-Current Diagnosis Mode
3x Clocks Low-
Current Mode Clock for Error Mode
1x/2x
Display
SDI
SDO
CLK
OEN
LD
Current
≤ 0.8mA GEF = Global Error Flag
Data1 Data2
Temperature Error Code
Data2
Data1
GEF GEF
T/O or S Error Code
Data0
Rising Edge of OEN
Acquisition of Error Status
Display
SDI
SDO
CLK
OEN
LD
1024x
1024x
3x Clocks
Low-Current
Mode Clock for Error
Mode 1x/2x
Falling Edge of LD; Error Register is cop-
ied into Shift Register
O or S Error Code
from Test Pattern
1024x
GEF = Global Error Flag
2µs Low-Current Diagnosis Mode
≤ 100mA ≤ 100mA
Current
≤ 0.8mA
Data2 Data3
External all 1s Test Pattern
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 18 - 24
AS1109
Datasheet - Application Information
9.2 Cascading Devices
To cascade multiple AS1109 devices, pin SDO must be connected to pin SDI of the next AS1 109 (see Figure 23). At each rising edge of CLK the
LSB of the shift register will be written into the shift register SDI of the next AS1109 in the chain. Data at the SDI pin is clocked in at the rising
edge of the CLK pulse and is clocked out at the SDO pin 8.5 clock cycles later at the falling edge of the CLK pulse.
Note: When n*AS1109 devices are in one chain, n*8 clock pulses are needed to latch-in the input data.
Figure 23. Cascading AS1109 Devices
9.3 Constant Current
In LED display applications, the AS1109 provides virtually no current variations from channel-to-channel and from AS1109-to-AS1109. This is
mostly due to 2 factors:
While IOUT ≥ 50mA, the maximum current skew is less than ±2% between channels and less than ±2% between AS1109 devices.
In the saturation region, the characteristics curve of the output stage is flat (see Figure 5 on page 6). Thus, the outp ut current can be kept
constant regardless of the variations of LED forward voltages (VF).
9.4 Adjusting Output Current
The AS1109 scales up the reference current (IREF) set by external resistor (REXT) to sink a current (IOUT) at each output port. As shown in
Figure 3 on page 6 the output current in the saturation region is extremely flat so that it is possible to define it as target current (IOUT TARGET).
IOUT TARGET can be calculated by: VREXT = 1.253V (EQ 1)
IREF = VREXT/REXT (if the other end of REXT is connected to ground) (EQ 2)
IOUT TARGET = IREF*15 = (1.253V/REXT)*15 (EQ 3)
Where:
REXT is the resistance of the external resistor connected to pin REXT.
VREXT is the voltage on pin REXT.
The magnitude of current (as a function of REXT) is around 100mA at 186Ω, 50.52mA at 372Ω and 25.26mA at 744Ω. Figure 3 on page 6
shows the relationship curve between the IOUT TARGET of each channel and the corresponding external resistor (REXT).
AS1109 #n-1
SDI SDO
CLK LD OEN
SDI
CLK
LD
OEN
AS1109 #1
SDI SDO
CLK LD OEN
AS1109 #2
SDI SDO
CLK LD OEN
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 19 - 24
AS1109
Datasheet - Application Information
9.5 Package Power Dissipation
The maximum allowable package power dissipation (PD) is determined as:
PD(MAX) = (TJ-TAMB)/RTH(J-A) (EQ 4)
When 8 output channels are turned on simultaneously, the actual package power dissipation is:
PD(ACT) = (IDD*VDD) + (IOUT*Duty*VDS*8) (EQ 5)
Therefore, to keep PD(ACT) ≤ PD(MAX), the allowable maximum output current as a function of duty cycle is:
IOUT = {[(TJ-TAMB)/RTH(J-A)]-(IDD*VDD)}/VDS/Duty/8 (EQ 6)
Where:
TJ = 150ºC
9.6 Delayed Outputs
The AS1109 has graduated delay circuits between outputs. These delay circuits can be found between OUTNn and constant current block.
The fixed delay time is 20 ns (typ) where OUTN0 has no delay , OUTN1 has 20ns delay, OUTN2 has 40ns delay ... OUTN7 has 140ns delay. This
delay prevents large inrush currents, which reduce power supply bypass capacitor requirements when the outputs turn on (see Figure 12 on
page 9)
9.7 Switching-Noise Reduction
LED drivers are frequently used in switch-mode applications which normally exhibit switching noise due to parasitic inductance on the PCB.
9.8 Load Supply Voltage
Considering the package power dissipation limits (see EQ 4:6), the AS1109 should be operated within the range of
VDS = 0.4 to 1.0V.
For example, if VLED is higher than 5V, VDS may be so hi gh th at PD(ACT) > PD(MAX) where VDS = VLED - VF. In this case, the lowest possible
supply voltage or a voltage reducer (VDROP) should be used. The voltage reducer allows
VDS = (VLED -VF) - VDROP.
Note: Resistors or zener diodes can be used as a voltage reducer as shown in Figure 24.
Figure 24. Voltage Reducer using Resistor (Left) and Zener Diode (Right)
AS1109
VDS
VF
Voltage Supply
}
VLED VDROP
AS1109
VDS
VF
VLED
VDROP
V o ltage Supply
{
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 20 - 24
AS1109
Datasheet - Package Drawings and Markings
10 Package Drawings and Markings
The product is available in a 16-pin SOIC-150, 16-pin QSOP-150, and 16-pin QFN 4x4mm package.
Figure 25. 16-pin SOIC-150 Package
Marking: YYWWRZZ.
YY WW RZZ
Last two digits of the current year Manufacturing Week Plant identifier Traceability code
Symbol Min Nom Max
A--1.75
A1 0.10 - 0.25
A2 1.25 - -
b0.31-0.51
c0.17-0.25
D - 9.90 BSC -
E - 6.00 BSC -
E1 - 3.90 BSC -
e - 1.27 BSC -
L0.40-1.27
L1 - 1.40 REF -
L2 - 0.25 BSC -
R0.07 - -
Symbol Min Nom Max
R1 0.07 -
h0.25-0.50
Θ0º - 8º
Θ1 5º - 15º
Θ20º - -
aaa - 0.10 -
bbb - 0.20 -
ccc - 0.10 -
ddd - 0.25 -
eee - 0.10 -
fff - 0.15 -
ggg - 0.15 -
N16
AS1109B
YYWWRZZ
Notes:
1. Dimensioning & tolerancing conform
to ASME Y14.5M-1994.
2. All dimensions are in millimeters.
Angles are in degrees.
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 21 - 24
AS1109
Datasheet - Package Drawings and Markings
Figure 26. 16-pin QSOP-150 Package
Marking: YYWWRZZ.
YY WW RZZ
Last two digits of the current year Manufacturing Week Plant identifier Traceability code
Symbol Min Nom Max
A- -1.75
A1 0.10 - 0.25
A2 1.24 - -
b 0.20 - 0.30
c 0.15 - 0.25
D 4.90 BSC
E 6.00 BSC
E1 3.91 BSC
e 0.635 BSC
L 0.41 - 1.27
L1 1.04 REF
L2 0.25 BSC
R0.08 - -
R1 0.08 - -
h 0.25 - 0.51
Θ0º - 8º
Θ15º - 15º
Θ20º - -
aaa - 0.10 -
bbb - 0.20 -
ccc - 0.10 -
ddd - 0.18 -
eee - 0.10 -
fff - 0.15 -
N16
Notes:
1. Dimensioning & tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. Datums A & B to be determined at Datum H.
AS1109B
YYWWRZZ
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 22 - 24
AS1109
Datasheet - Package Drawings and Markings
Figure 27. 16 -pin QFN 4x4mm Package
Marking: YYWWQZZ.
YY WW QZZ
Last two digits of the current year Manufacturing Week Plant identifier Traceability code
Symbol Min Nom Max
A 0.70 0.75 0.80
A1 0 0.02 0.05
A3 0.20 REF
L 0.45 0.55 0.65
b 0.25 0.30 0.35
D 4.00 BSC
E 4.00 BSC
e 0.65 BSC
D2 2.00 2.15 2.25
E2 2.00 2.15 2.25
aaa - 0.15 -
bbb - 0.10 -
ccc - 0.10 -
ddd - 0.05 -
eee - 0.08 -
fff - 0.10 -
N16
Notes:
1. Dimensioning & tolerancing conform to ASME Y14.5M-1994.
2. All dimensions are in millimeters. Angles are in degrees.
3. Coplanarity applies to the exposed heat slug as well as the terminal.
4. Radius on terminal is optional.
5. N is the total number of terminals.
AS
1109B
YYWW
QZZ
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 23 - 24
AS1109
Datasheet - Ordering Information
11 Ordering Information
The device is available as the standard products shown in Table 9.
Note: All products are RoHS compliant.
Buy our products or get free samples online at www.ams.com/ICdirect
Technical Support is available at www.ams.com/Technical-Support
For further information and requests, email us at sales@ams.com
(or) find your local distributor at www.ams.com/distributor
Table 9. Ordering Information
Ordering Code Marking Description Delivery Form Package
AS1109-BSOU AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tubes 16-pin SOIC-150
AS1109-BSOT AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tape and Reel 16-pin SOIC-150
AS1109-BSSU AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tubes 16-pin QSOP-150
AS1109-BSST AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tape and Reel 16-pin QSOP-150
AS1109-BQFR AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tray 16-pin QFN (4x4mm)
AS1109-BQFT AS1109B Constant-Current, 8-Bit LED Driver with Diagnostics Tape and Reel 16-pin QFN (4x4mm)
www.ams.com/LED-Driver-ICs/AS1109 Revision 1.21 24 - 24
AS1109
Datasheet - Ordering Information
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reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the
copyright owner.
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warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described
devices from patent infringement. ams AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior
to designing this product into a system, it is necessary to check with ams AG for current information. This product is intended for use in normal
commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability
applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing
by ams AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard
production flow, such as test flow or test location.
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