Quad Channel, 128-/256-Position, I2C/SPI,
Nonvolatile Digital Potentiometer
Data Sheet AD5124/AD5144/AD5144A
Rev. A Document Feedback
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FEATURES
10 kΩ and 100 kΩ resistance options
Resistor tolerance: 8% maximum
Wiper current: ±6 mA
Low temperature coefficient: 35 ppm/°C
Wide bandwidth: 3 MHz
Fast start-up time < 75 μs
Linear gain setting mode
Single- and dual-supply operation
Independent logic supply: 1.8 V to 5.5 V
Wide operating temperature: −40°C to +125°C
4 mm × 4 mm package option
4 kV ESD protection
APPLICATIONS
Portable electronics level adjustment
LCD panel brightness and contrast controls
Programmable filters, delays, and time constants
Programmable power supplies
FUNCTIONAL BLOCK DIAGRAM
V
DD
LRDAC
V
SS
GND WP
V
LOGIC
7/8
SERIAL
INTERFACE
POWER-ON
RESET RDAC1
INPUT
REGISTER 1
RDAC2
INPUT
REGISTER 2
RDAC3
INPUT
REGISTER 3
RDAC4
INPUT
REGISTER 4
EEPROM
MEMORY
A1
W1
B1
A2
W2
B2
A3
W3
B3
A4
W4
B4
AD5124/AD5144
SYNC/ADDR0
SCLK/SCL
SDI/SDA
SDO/ADDR1
DIS
RESET
10877-001
Figure 1. AD5124/AD5144 24-Lead LFCSP
GENERAL DESCRIPTION
The AD5124/AD5144/AD5144A potentiometers provide a
nonvolatile solution for 128-/256-position adjustment applications,
offering guaranteed low resistor tolerance errors of ±8% and up to
±6 mA current density in the Ax, Bx, and Wx pins.
The low resistor tolerance and low nominal temperature coefficient
simplify open-loop applications as well as applications requiring
tolerance matching.
The linear gain setting mode allows independent programming
of the resistance between the digital potentiometer terminals,
through the RAW and RWB string resistors, allowing very accurate
resistor matching.
The high bandwidth and low total harmonic distortion (THD)
ensure optimal performance for ac signals, making these devices
suitable for filter design.
The low wiper resistance of only 40 Ω at the ends of the resistor
array allow for pin-to-pin connection.
The wiper values can be set through an SPI-/I2C-compatible digital
interface that is also used to read back the wiper register and
EEPROM contents.
The AD5124/AD5144/AD5144A are available in a compact,
24-lead, 4 mm × 4 mm LFCSP and a 20-lead TSSOP. The parts
are guaranteed to operate over the extended industrial temperature
range of −40°C to +125°C.
Table 1. Family Models
Model Channel Position Interface Package
AD51231 Quad 128 I2C LFCSP
AD5124 Quad 128 SPI/I2C LFCSP
AD5124 Quad 128 SPI TSSOP
AD51431 Quad 256 I2C LFCSP
AD5144 Quad 256 SPI/I2C LFCSP
AD5144 Quad 256 SPI TSSOP
AD5144A Quad 256 I2C TSSOP
AD5122 Dual 128 SPI LFCSP/TSSOP
AD5122A Dual 128 I2C LFCSP/TSSOP
AD5142 Dual 256 SPI LFCSP/TSSOP
AD5142A Dual 256 I2C LFCSP/TSSOP
AD5121 Single 128 SPI/I2C LFCSP
AD5141 Single 256 SPI/I2C LFCSP
1 Two potentiometers and two rheostats.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 2 of 36
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Functional Block Diagrams—TSSOP ............................................ 3
Specifications ..................................................................................... 4
Electrical Characteristics—AD5124 .......................................... 4
Electrical Characteristics—AD5144 and AD5144A ................ 7
Interface Timing Specifications ................................................ 10
Shift Register and Timing Diagrams ....................................... 11
Absolute Maximum Ratings .......................................................... 13
Thermal Resistance .................................................................... 13
ESD Caution ................................................................................ 13
Pin Configurations and Function Descriptions ......................... 14
Typical Performance Characteristics ........................................... 17
Test Circuits ..................................................................................... 22
Theory of Operation ...................................................................... 23
RDAC Register and EEPROM .................................................. 23
Input Shift Register .................................................................... 23
Serial Data Digital Interface Selection, DIS ............................ 23
SPI Serial Data Interface ............................................................ 23
I2C Serial Data Interface ............................................................ 25
I2C Address .................................................................................. 25
Advanced Control Modes ......................................................... 27
EEPROM or RDAC Register Protection ................................. 28
Load RDAC Input Register (LRDAC) ..................................... 28
RDAC Architecture .................................................................... 31
Programming the Variable Resistor ......................................... 31
Programming the Potentiometer Divider ............................... 32
Terminal Voltage Operating Range ......................................... 32
Power-Up Sequence ................................................................... 32
Layout and Power Supply Biasing ............................................ 32
Outline Dimensions ....................................................................... 33
Ordering Guide .......................................................................... 34
REVISION HISTORY
12/12—Rev. 0 to Rev. A
Changes to Table 12 and Table 13 ................................................ 25
10/12—Revision 0: Initial Version
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 3 of 36
FUNCTIONAL BLOCK DIAGRAMS—TSSOP
V
DD
V
SS
GND
V
LOGIC
7/8
SPI
SERIAL
INTERFACE
SDO
SCLK
SDI
POWER-ON
RESET
SYNC
RDAC 1
INPUT
REGISTER 1
RDAC 2
INPUT
REGISTER 2
RDAC 3
INPUT
REGISTER 3
RDAC 4
INPUT
REGISTER 4
EEPROM
MEMORY
A1
W1
B1
A2
W2
B2
A3
W3
B3
A4
W4
B4
AD5124/AD5144
10877-002
Figure 2. AD5124/AD5144 20-Lead TSSOP
V
DD
VSS
GND
V
LOGIC
8
I
2
C
SERIAL
INTERFACE
ADDR
SCL
SDA
POWER-ON
RESET
RESET
RDAC 1
INPUT
REGISTER 1
RDAC 2
INPUT
REGISTER 2
RDAC 3
INPUT
REGISTER 3
RDAC 4
INPUT
REGISTER 4
EEPROM
MEMORY
A1
W1
B1
A2
W2
B2
A3
W3
B3
A4
W4
B4
AD5144A
10877-003
Figure 3. AD5144A 20-Lead TSSOP
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 4 of 36
SPECIFICATIONS
ELECTRICAL CHARACTERISTICS—AD5124
VDD = 2.3 V to 5.5 V, VSS = 0 V; VDD = 2.25 V to 2.75 V, VSS = −2.25 V to −2.75 V; VLOGIC = 1.8 V to 5.5 V, −40°C < TA < +125°C, unless
otherwise noted.
Table 2.
Parameter Symbol Test Conditions/Comments Min Typ 1 Max Unit
DC CHARACTERISTICS—RHEOSTAT
MODE (ALL RDACs)
Resolution N 7 Bits
Resistor Integral Nonlinearity2 R-INL RAB = 10 kΩ
VDD ≥ 2.7 V −1 ±0.1 +1 LSB
VDD < 2.7 V −2.5 ±1 +2.5 LSB
RAB = 100 kΩ
VDD ≥ 2.7 V −0.5 ±0.1 +0.5 LSB
VDD < 2.7 V −1 ±0.25 +1 LSB
Resistor Differential Nonlinearity2 R-DNL −0.5 ±0.1 +0.5 LSB
Nominal Resistor Tolerance ΔRAB/RAB −8 ±1 +8 %
Resistance Temperature Coefficient3 (ΔRAB/RAB)/ΔT × 106 Code = full scale 35 ppm/°C
Wiper Resistance
3
R
W
Code = zero scale
R
AB
= 10 kΩ
55
125
Ω
RAB = 100 kΩ 130 400 Ω
Bottom Scale or Top Scale RBS or RTS
RAB = 10 kΩ 40 80 Ω
RAB = 100 kΩ 60 230 Ω
Nominal Resistance Match RAB1/RAB2 Code = 0xFF −1 ±0.2 +1 %
DC CHARACTERISTICS—POTENTIOMETER
DIVIDER MODE (ALL RDACs)
Integral Nonlinearity4 INL
RAB = 10 kΩ −0.5 ±0.1 +0.5 LSB
RAB = 100 kΩ −0.25 ±0.1 +0.25 LSB
Differential Nonlinearity4 DNL −0.25 ±0.1 +0.25 LSB
Full-Scale Error VWFSE
RAB = 10 kΩ −1.5 −0.1 LSB
RAB = 100 kΩ −0.5 ±0.1 +0.5 LSB
Zero-Scale Error VWZSE
RAB = 10 kΩ 1 1.5 LSB
RAB = 100 kΩ 0.25 0.5 LSB
Voltage Divider Temperature
Coefficient3
(ΔVW/VW)/ΔT × 106 Code = half scale ±5 ppm/°C
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 5 of 36
Parameter Symbol Test Conditions/Comments Min Typ 1 Max Unit
RESISTOR TERMINALS
Maximum Continuous Current IA, IB, and IW
RAB = 10 kΩ −6 +6 mA
RAB = 100 kΩ −1.5 +1.5 mA
Terminal Voltage Range
5
V
SS
V
DD
V
Capacitance A, Capacitance B3 CA, CB f = 1 MHz, measured to GND,
code = half scale
RAB = 10 kΩ 25 pF
RAB = 100 kΩ 12 pF
Capacitance W3 CW f = 1 MHz, measured to GND,
code = half scale
RAB = 10 kΩ 12 pF
RAB = 100 kΩ 5 pF
Common-Mode Leakage Current3 VA = VW = VB −500 ±15 +500 nA
DIGITAL INPUTS
Input Logic3
High VINH VLOGIC = 1.8 V to 2.3 V 0.8 × VLOGIC V
VLOGIC = 2.3 V to 5.5 V 0.7 × VLOGIC V
Low
V
INL
0.2 × V
LOGIC
V
Input Hysteresis3 VHYST 0.1 × VLOGIC V
Input Current3 IIN ±1 µA
Input Capacitance3 CIN 5 pF
DIGITAL OUTPUTS
Output High Voltage3 VOH RPULL-UP = 2.2 kΩ to VLOGIC VLOGIC V
Output Low Voltage3 VOL ISINK = 3 mA 0.4 V
ISINK = 6 mA, VLOGIC > 2.3 V 0.6 V
Three-State Leakage Current −1 +1 µA
Three-State Output Capacitance 2 pF
POWER SUPPLIES
Single-Supply Power Range VSS = GND 2.3 5.5 V
Dual-Supply Power Range ±2.25 ±2.75 V
Logic Supply Range Single supply, VSS = GND 1.8 VDD V
Dual supply, VSS < GND 2.25 VDD V
Positive Supply Current IDD VIH = VLOGIC or VIL = GND
V
DD
= 5.5 V
0.7
5.5
µA
VDD = 2.3 V 400 nA
Negative Supply Current ISS VIH = VLOGIC or VIL = GND −5.5 −0.7 µA
EEPROM Store Current3, 6 IDD_EEPROM_STORE VIH = VLOGIC or VIL = GND 2 mA
EEPROM Read Current3, 7 IDD_EEPROM_READ VIH = VLOGIC or VIL = GND 320 µA
Logic Supply Current ILOGIC VIH = VLOGIC or VIL = GND 1 120 nA
Power Dissipation8 PDISS VIH = VLOGIC or VIL = GND 3.5 µW
Power Supply Rejection Ratio PSRR ∆VDD/∆VSS = VDD ± 10%,
code = full scale
−66 −60 dB
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 6 of 36
Parameter Symbol Test Conditions/Comments Min Typ 1 Max Unit
DYNAMIC CHARACTERISTICS9
Bandwidth BW −3 dB
RAB = 10 kΩ 3 MHz
RAB = 100 kΩ 0.43 MHz
Total Harmonic Distortion
THD
V
DD
/V
SS
= ±2.5 V, V
A
= 1 V rms,
VB = 0 V, f = 1 kHz
RAB = 10 kΩ −80 dB
RAB = 100 kΩ −90 dB
Resistor Noise Density eN_WB Code = half scale, TA = 25°C,
f = 10 kHz
RAB = 10 kΩ 7 nV/√Hz
RAB = 100 kΩ 20 nV/√Hz
VW Settling Time tS VA = 5 V, VB = 0 V, from
zero scale to full scale,
±0.5 LSB error band
R
AB
= 10 kΩ
2
µs
RAB = 100 kΩ 12 µs
Crosstalk (CW1/CW2) CT RAB = 10 kΩ 10 nV-sec
RAB = 100 kΩ 25 nV-sec
Analog Crosstalk CTA −90 dB
Endurance10 TA = 25°C 1 Mcycles
100 kcycles
Data Retention11 50 Years
1 Typical values represent average readings at 25°C, VDD = 5 V, VSS = 0 V, and VLOGIC = 5 V.
2 Resistor integral nonlinearity error (R-INL) is the deviation from an ideal value measured between the maximum resistance and the minimum resistance wiper
positions. R-DNL measures the relative step change from ideal between successive tap positions. The maximum wiper current is limited to (0.7 × VDD)/RAB.
3 Guaranteed by design and characterization, not subject to production test.
4 INL and DNL are measured at VWB with the RDAC configured as a potentiometer divider similar to a voltage output DAC. VA = VDD and VB = 0 V. DNL specification limits
of ±1 LSB maximum are guaranteed monotonic operating conditions.
5 Resistor Terminal A, Resistor Terminal B, and Resistor Terminal W have no limitations on polarity with respect to each other. Dual-supply operation enables ground
referenced bipolar signal adjustment.
6 Different from operating current; supply current for EEPROM program lasts approximately 30 ms.
7 Different from operating current; supply current for EEPROM read lasts approximately 20 µs.
8 PDISS is calculated from (IDD × VDD) + (ILOGIC × VLOGIC).
9 All dynamic characteristics use VDD/VSS = ±2.5 V, and VLOGIC = 2.5 V.
10 Endurance is qualified to 100,000 cycles per JEDEC Standard 22, Method A117 and measured at −40°C to +125°C.
11 Retention lifetime equivalent at junction temperature (TJ) = 125°C per JEDEC Standard 22, Method A117. Retention lifetime, based on an activation energy of 1 eV,
derates with junction temperature in the Flash/EE memory.
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 7 of 36
ELECTRICAL CHARACTERISTICS—AD5144 AND AD5144A
VDD = 2.3 V to 5.5 V, VSS = 0 V; VDD = 2.25 V to 2.75 V, VSS = −2.25 V to −2.75 V; VLOGIC = 1.8 V to 5.5 V, −40°C < TA < +125°C, unless
otherwise noted.
Table 3.
Parameter Symbol Test Conditions/Comments Min Typ 1 Max Unit
DC CHARACTERISTICS—RHEOSTAT
MODE (ALL RDACs)
Resolution N 8 Bits
Resistor Integral Nonlinearity2 R-INL RAB = 10 kΩ
V
DD
≥ 2.7 V
−2
±0.2
+2
LSB
VDD < 2.7 V −5 ±1.5 +5 LSB
RAB = 100 kΩ
VDD ≥ 2.7 V −1 ±0.1 +1 LSB
VDD < 2.7 V −2 ±0.5 +2 LSB
Resistor Differential Nonlinearity2 R-DNL −0.5 ±0.2 +0.5 LSB
Nominal Resistor Tolerance ΔRAB/RAB −8 ±1 +8 %
Resistance Temperature Coefficient3 (ΔRAB/RAB)/ΔT × 106 Code = full scale 35 ppm/°C
Wiper Resistance3 RW Code = zero scale
RAB = 10 kΩ 55 125 Ω
RAB = 100 kΩ 130 400 Ω
Bottom Scale or Top Scale RBS or RTS
RAB = 10 kΩ 40 80 Ω
RAB = 100 kΩ 60 230 Ω
Nominal Resistance Match RAB1/RAB2 Code = 0xFF −1 ±0.2 +1 %
DC CHARACTERISTICS—POTENTIOMETER
DIVIDER MODE (ALL RDACs)
Integral Nonlinearity4 INL
RAB = 10 kΩ −1 ±0.2 +1 LSB
RAB = 100 kΩ −0.5 ±0.1 +0.5 LSB
Differential Nonlinearity4 DNL −0.5 ±0.2 +0.5 LSB
Full-Scale Error VWFSE
RAB = 10 kΩ −2.5 −0.1 LSB
RAB = 100 kΩ −1 ±0.2 +1 LSB
Zero-Scale Error VWZSE
RAB = 10 kΩ 1.2 3 LSB
RAB = 100 kΩ 0.5 1 LSB
Voltage Divider Temperature
Coefficient3
(ΔVW/VW)/ΔT × 106 Code = half scale ±5 ppm/°C
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 8 of 36
Parameter Symbol Test Conditions/Comments Min Typ 1 Max Unit
RESISTOR TERMINALS
Maximum Continuous Current IA, IB, and IW
RAB = 10 kΩ −6 +6 mA
RAB = 100 kΩ −1.5 +1.5 mA
Terminal Voltage Range
5
V
SS
V
DD
V
Capacitance A, Capacitance B3 CA, CB f = 1 MHz, measured to GND,
code = half scale
RAB = 10 kΩ 25 pF
RAB = 100 kΩ 12 pF
Capacitance W3 CW f = 1 MHz, measured to GND,
code = half scale
RAB = 10 kΩ 12 pF
RAB = 100 kΩ 5 pF
Common-Mode Leakage Current3 VA = VW = VB −500 ±15 +500 nA
DIGITAL INPUTS
Input Logic3
High VINH VLOGIC = 1.8 V to 2.3 V 0.8 × VLOGIC V
VLOGIC = 2.3 V to 5.5 V 0.7 × VLOGIC V
Low
INL
0.2 × V
LOGIC
V
Input Hysteresis3 VHYST 0.1 × VLOGIC V
Input Current3 IIN ±1 µA
Input Capacitance3 CIN 5 pF
DIGITAL OUTPUTS
Output High Voltage3 VOH RPULL-UP = 2.2 kΩ to VLOGIC VLOGIC V
Output Low Voltage3 VOL ISINK = 3 mA 0.4 V
ISINK = 6 mA, VLOGIC > 2.3 V 0.6 V
Three-State Leakage Current −1 +1 µA
Three-State Output Capacitance 2 pF
POWER SUPPLIES
Single-Supply Power Range VSS = GND 2.3 5.5 V
Dual-Supply Power Range ±2.25 ±2.75 V
Logic Supply Range Single supply, VSS = GND 1.8 VDD V
Dual supply, VSS < GND 2.25 VDD V
Positive Supply Current IDD VIH = VLOGIC or VIL = GND
V
DD
= 5.5 V
0.7
5.5
µA
VDD = 2.3 V 400 nA
Negative Supply Current ISS VIH = VLOGIC or VIL = GND −5.5 −0.7 µA
EEPROM Store Current3, 6 IDD_EEPROM_STORE VIH = VLOGIC or VIL = GND 2 mA
EEPROM Read Current3, 7 IDD_EEPROM_READ VIH = VLOGIC or VIL = GND 320 µA
Logic Supply Current ILOGIC VIH = VLOGIC or VIL = GND 1 120 nA
Power Dissipation8 PDISS VIH = VLOGIC or VIL = GND 3.5 µW
Power Supply Rejection Ratio PSRR ∆VDD/∆VSS = VDD ± 10%,
code = full scale
−66 −60 dB
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 9 of 36
Parameter Symbol Test Conditions/Comments Min Typ 1 Max Unit
DYNAMIC CHARACTERISTICS9
Bandwidth BW −3 dB
RAB = 10 kΩ 3 MHz
RAB = 100 kΩ 0.43 MHz
Total Harmonic Distortion
V
DD
/V
SS
= ±2.5 V, V
A
= 1 V rms,
VB = 0 V, f = 1 kHz
RAB = 10 kΩ −80 dB
RAB = 100 kΩ −90 dB
Resistor Noise Density eN_WB Code = half scale, TA = 25°C,
f = 10 kHz
RAB = 10 kΩ 7 nV/√Hz
RAB = 100 kΩ 20 nV/√Hz
VW Settling Time tS VA = 5 V, VB = 0 V, from
zero scale to full scale,
±0.5 LSB error band
R
AB
= 10 kΩ
2
µs
RAB = 100 kΩ 12 µs
Crosstalk (CW1/CW2) CT RAB = 10 kΩ 10 nV-sec
RAB = 100 kΩ 25 nV-sec
Analog Crosstalk CTA −90 dB
Endurance10 TA = 25°C 1 Mcycles
100 kcycles
Data Retention11 50 Years
1 Typical values represent average readings at 25°C, VDD = 5 V, VSS = 0 V, and VLOGIC = 5 V.
2 Resistor integral nonlinearity error (R-INL) is the deviation from an ideal value measured between the maximum resistance and the minimum resistance wiper
positions. R-DNL measures the relative step change from ideal between successive tap positions. The maximum wiper current is limited to (0.7 × VDD)/RAB.
3 Guaranteed by design and characterization, not subject to production test.
4 INL and DNL are measured at VWB with the RDAC configured as a potentiometer divider similar to a voltage output DAC. VA = VDD and VB = 0 V. DNL specification limits
of ±1 LSB maximum are guaranteed monotonic operating conditions.
5 Resistor Terminal A, Resistor Terminal B, and Resistor Terminal W have no limitations on polarity with respect to each other. Dual-supply operation enables ground
referenced bipolar signal adjustment.
6 Different from operating current; supply current for EEPROM program lasts approximately 30 ms.
7 Different from operating current; supply current for EEPROM read lasts approximately 20 µs.
8 PDISS is calculated from (IDD × VDD) + (ILOGIC × VLOGIC).
9 All dynamic characteristics use VDD/VSS = ±2.5 V, and VLOGIC = 2.5 V.
10 Endurance is qualified to 100,000 cycles per JEDEC Standard 22, Method A117 and measured at −40°C to +125°C.
11 Retention lifetime equivalent at junction temperature (TJ) = 125°C per JEDEC Standard 22, Method A117. Retention lifetime, based on an activation energy of 1 eV,
derates with junction temperature in the Flash/EE memory.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 10 of 36
INTERFACE TIMING SPECIFICATIONS
VLOGIC = 1.8 V to 5.5 V; all specifications TMIN to TMAX, unless otherwise noted.
Table 4. SPI Interface
Parameter1 Test Conditions/Comments Min Typ Max Unit Description
t1 VLOGIC > 1.8 V 20 ns SCLK cycle time
VLOGIC = 1.8 V 30 ns
t2 VLOGIC > 1.8 V 10 ns SCLK high time
VLOGIC = 1.8 V 15 ns
t3 VLOGIC > 1.8 V 10 ns SCLK low time
VLOGIC = 1.8 V 15 ns
t4 10 ns SYNC-to-SCLK falling edge setup time
t5 5 ns Data setup time
t6 5 ns Data hold time
t7 10 ns SYNC rising edge to next SCLK fall ignored
t82 20 ns Minimum SYNC high time
t93 50 ns SCLK rising edge to SDO valid
t10 500 ns SYNC rising edge to SDO pin disable
1 All input signals are specified with tr = tf = 1 ns/V (10% to 90% of VDD) and timed from a voltage level of (VIL + VIH)/2.
2 Refer to tEEPROM_PROGRAM and tEEPROM_READBACK for memory commands operations (see Table 6).
3 RPULL_UP = 2.2 kΩ to VDD with a capacitance load of 168 pF.
Table 5. I2C Interface
Parameter1 Test Conditions/Comments Min Typ Max Unit Description
f
SCL2
Standard mode
100
kHz
Serial clock frequency
Fast mode 400 kHz
t1 Standard mode 4.0 µs SCL high time, tHIGH
Fast mode 0.6 µs
t2 Standard mode 4.7 µs SCL low time, tLOW
Fast mode 1.3 µs
t3 Standard mode 250 ns Data setup time, tSU; DAT
Fast mode 100 ns
t4 Standard mode 0 3.45 µs Data hold time, tHD; DAT
Fast mode 0 0.9 µs
t5 Standard mode 4.7 µs Setup time for a repeated start condition, tSU; STA
Fast mode 0.6 µs
t6 Standard mode 4 µs Hold time (repeated) for a start condition, tHD; STA
Fast mode 0.6 µs
t7 Standard mode 4.7 µs Bus free time between a stop and a start condition, tBUF
Fast mode 1.3 µs
t8 Standard mode 4 µs Setup time for a stop condition, tSU; STO
Fast mode
0.6
µs
t9 Standard mode 1000 ns Rise time of SDA signal, tRDA
Fast mode 20 + 0.1 CL 300 ns
t10 Standard mode 300 ns Fall time of SDA signal, tFDA
Fast mode 20 + 0.1 CL 300 ns
t11 Standard mode 1000 ns Rise time of SCL signal, tRCL
Fast mode 20 + 0.1 CL 300 ns
t11A Standard mode 1000 ns Rise time of SCL signal after a repeated start condition
and after an acknowledge bit, tRCL1 (not shown in Figure 5)
Fast mode 20 + 0.1 CL 300 ns
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 11 of 36
Parameter1 Test Conditions/Comments Min Typ Max Unit Description
t12 Standard mode 300 ns Fall time of SCL signal, tFCL
Fast mode 20 + 0.1 CL 300 ns
tSP3 Fast mode 0 50 ns Pulse width of suppressed spike
1 Maximum bus capacitance is limited to 400 pF.
2 The SDA and SCL timing is measured with the input filters enabled. Switching off the input filters improves the transfer rate; however, it has a negative effect on the
EMC behavior of the part.
3 Input filtering on the SCL and SDA inputs suppresses noise spikes that are less than 50 ns for fast mode.
Table 6. Control Pins
Parameter Min Typ Max Unit Description
t1 1 μs End command to LRDAC falling edge
t2 50 ns Minimum LRDAC low time
t3 0.1 10 μs RESET low time
tEEPROM_PROGRAM1 15 50 ms Memory program time (not shown in Figure 8)
tEEPROM_READBACK 7 30 μs Memory readback time (not shown in Figure 8)
tPOWER_UP2 75 μs Start-up time (not shown in Figure 8)
tRESET 30 μs Reset EEPROM restore time (not shown in Figure 8)
1 EEPROM program time depends on the temperature and EEPROM write cycles. Higher timing is expected at lower temperatures and higher write cycles.
2 Maximum time after VDD − VSS is equal to 2.3 V.
SHIFT REGISTER AND TIMING DIAGRAMS
DATA BI TS
DB8DB15 (MSB) DB0 (L SB)
D7 D6 D5 D4 D3 D2 D1 D0
ADDRESS BITS
A0A1
A2C2 C1 C0 A3C3
CONTRO L BI TS
10877-004
DB7
Figure 4. Input Shift Register Contents
t
7
t
6
t
2
t
4
t
11
t
12
t
6
t
5
t
10
t
1
SCL
SD
A
PS S P
t
3
t
8
t
9
10877-005
Figure 5. I2C Serial Interface Timing Diagram (Typical Write Sequence)
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 12 of 36
C3
t
4
t
2
t
3
t
5
t
6
C2 C1 C0 D7 D6 D5 D2 D1 D0SDI
*PREVIO US CO M M A ND RE CEIV ED.
SCLK
SYNC
C3*SDO C2* C1* C0* D7* D6* D5* D2* D1* D0*
t
8
t
9
t
10
t
7
t
1
10877-006
Figure 6. SPI Serial Interface Timing Diagram, CPOL = 0, CPHA = 1
C3
t
4
t
2
t
3
t
5
t
6
C2 C1 C0 D7 D6 D5 D2 D1 D0
SDI
*
PREV IO US COMMAND RECE IVE D.
SCLK
SYNC
C3*
SDO C2* C1* C0* D7* D6* D5* D2* D1* D0*
t
8
t
9
t
10
t
7
t
1
10877-007
Figure 7. SPI Serial Interface Timing Diagram, CPOL = 1, CPHA = 0
SPI INTERFACE
I
2
C INTERFACE
SCL
SCLK
SYNC
SDA
LRDAC
RESET
P
t
1
t
2
t
3
10877-008
Figure 8. Control Pins Timing Diagram
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 13 of 36
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 7.
Parameter Rating
VDD to GND −0.3 V to +7.0 V
VSS to GND +0.3 V to −7.0 V
VDD to VSS 7 V
VLOGIC to GND −0.3 V to VDD + 0.3 V or
+7.0 V (whichever is less)
VA, VW, VB to GND VSS − 0.3 V, VDD + 0.3 V
IA, IW, IB
Pulsed1
Frequency > 10 kHz
RAW = 10 kΩ ±6 mA/d2
RAW = 100 kΩ ±1.5 mA/d2
Frequency ≤ 10 kHz
R
AW
= 10 kΩ
±6 mA/√d
2
RAW = 100 kΩ ±1.5 mA/√d2
Digital Inputs −0.3 V to VLOGIC + 0.3 V or
+7 V (whichever is less)
Operating Temperature Range, TA3 −40°C to +125°C
Maximum Junction Temperature,
TJ Maximum
150°C
Storage Temperature Range −65°C to +150°C
Reflow Soldering
Peak Temperature 260°C
Time at Peak Temperature
20 sec to 40 sec
Package Power Dissipation
(T
J
max − T
A
)/θ
JA
ESD4 4 kV
FICDM 1.5 kV
1 Maximum terminal current is bounded by the maximum current handling of
the switches, maximum power dissipation of the package, and maximum
applied voltage across any two of the A, B, and W terminals at a given
resistance.
2 d = pulse duty factor.
3 Includes programming of EEPROM memory.
4 Human body model (HBM) classification.
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.
THERMAL RESISTANCE
θJA is defined by the JEDEC JESD51 standard, and the value is
dependent on the test board and test environment.
Table 8. Thermal Resistance
Package Type θJA θJC Unit
24-Lead LFCSP 351 3 °C/W
20-Lead TSSOP 1431 45 °C/W
1 JEDEC 2S2P test board, still air (0 m/sec airflow).
ESD CAUTION
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 14 of 36
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
1
2
3
4
5
6
7
8
9
10
GND
A1
W1
W3
A3
B1
SYNC
A2
V
SS
B3
20
19
18
17
16
15
14
13
12
11
SDI
SCLK
V
LOGIC
W4
B4
V
DD
W2
B2
A4
SDO
AD5124/
AD5144
TOP VI EW
(No t t o Scal e)
10877-010
Figure 9. 20-Lead TSSOP, SPI Interface Pin Configuration (AD5124/AD5144)
Table 9. 20-Lead TSSOP, SPI Interface Pin Function Descriptions (AD5124/AD5144)
Pin No. Mnemonic Description
1
SYNC
Synchronization Data Input, Active Low. When
SYNC
returns high, data is loaded into the input shift register.
2 GND Ground Pin, Logic Ground Reference.
3 A1 Terminal A of RDAC1. VSS ≤ VA ≤ VDD.
4 W1 Wiper Terminal of RDAC1. VSS ≤ VW ≤ VDD.
5 B1 Terminal B of RDAC1. VSS ≤ VB ≤ VDD.
6 A3 Terminal A of RDAC3. VSS ≤ VA ≤ VDD.
7 W3 Wiper Terminal of RDAC3. VSS ≤ VW ≤ VDD.
8 B3 Terminal B of RDAC3. VSS ≤ VB ≤ VDD.
9 VSS Negative Power Supply. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
10 A2 Terminal A of RDAC2. VSS ≤ VA ≤ VDD.
11 W2 Wiper Terminal of RDAC2. VSS ≤ VW ≤ VDD.
12
B2
Terminal B of RDAC2. V
SS
≤ V
B
≤ V
DD
.
13 A4 Terminal A of RDAC4. VSS ≤ VA ≤ VDD.
14 W4 Wiper Terminal of RDAC4. VSS ≤ VW ≤ VDD.
15 B4 Terminal B of RDAC4. VSS ≤ VB ≤ VDD.
16 VDD Positive Power Supply. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
17 VLOGIC Logic Power Supply; 1.8 V to VDD. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
18 SCLK Serial Clock Line. Data is clocked in at the logic low transition.
19 SDI Serial Data Input.
20 SDO Serial Data Output. This is an open-drain output pin, and it needs an external pull-up resistor.
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 15 of 36
1
2
3
4
5
6
7
8
9
10
GND
A1
W1
W3
A3
B1
RESET
A2
V
SS
B3
20
19
18
17
16
15
14
13
12
11
SDA
SCL
V
LOGIC
W4
B4
V
DD
W2
B2
A4
ADDR
AD5144A
TOP VI EW
(No t t o Scal e)
10877-011
Figure 10. 20-Lead TSSOP, I2C Interface Pin Configuration (AD5144A)
Table 10. 20-Lead TSSOP, I2C Interface Pin Function Descriptions (AD5144A)
Pin No. Mnemonic Description
1 RESET Hardware Reset Pin. Refresh the RDAC registers from EEPROM. RESET is activated at the logic low. If this pin is not
used, tie RESET to VLOGIC.
2 GND Ground Pin, Logic Ground Reference.
3 A1 Terminal A of RDAC1. VSS ≤ VA ≤ VDD.
4 W1 Wiper Terminal of RDAC1. VSS ≤ VW ≤ VDD.
5 B1 Terminal B of RDAC1. VSS ≤ VB ≤ VDD.
6 A3 Terminal A of RDAC3. VSS ≤ VA ≤ VDD.
7 W3 Wiper Terminal of RDAC3. VSS ≤ VW ≤ VDD.
8 B3 Terminal B of RDAC3. VSS ≤ VB ≤ VDD.
9
V
SS
Negative Power Supply. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
10 A2 Terminal A of RDAC2. VSS ≤ VA ≤ VDD.
11 W2 Wiper Terminal of RDAC2. VSS ≤ VW ≤ VDD.
12 B2 Terminal B of RDAC2. VSS ≤ VB ≤ VDD.
13 A4 Terminal A of RDAC4. VSS ≤ VA ≤ VDD.
14 W4 Wiper Terminal of RDAC4. VSS ≤ VW ≤ VDD.
15 B4 Terminal B of RDAC4. VSS ≤ VB ≤ VDD.
16 VDD Positive Power Supply. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
17 VLOGIC Logic Power Supply; 1.8 V to VDD. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
18 SCL Serial Clock Line. Data is clocked in at the logic low transition.
19 SDA Serial Data Input/Output.
20 ADDR Programmable Address for Multiple Package Decoding.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 16 of 36
10877-009
PIN 1
INDICATOR
1
GND 2
A1 3
W1 4B1 5
A3 6W3
15 VDD
16 VLOGIC
17 SCL/SCLK
NOTES
1. INTE RNALL Y CONNECT THE
EXPOSED PAD TO VSS.
18 DIS
14 B4
13 W4
7
B3 8
VSS 9
A2
11
B2 12
A4
10
W2 21 ADDR1/SDO
22 ADDR0/SYNC
23 LRDAC
24 RESET
20 WP
19 SDA/SDI
AD5124/
AD5144
TOP VIEW
(No t t o Scal e)
Figure 11. 24-Lead LFCSP Pin Configuration (AD5124/AD5144)
Table 11. 24-Lead LFCSP Pin Function Descriptions (AD5124/AD5144)
Pin No. Mnemonic Description
1 GND Ground Pin, Logic Ground Reference.
2 A1 Terminal A of RDAC1. VSS ≤ VA ≤ VDD.
3 W1 Wiper Terminal of RDAC1. VSS ≤ VW ≤ VDD.
4 B1 Terminal B of RDAC1. VSS ≤ VB ≤ VDD.
5 A3 Terminal A of RDAC3. VSS ≤ VA ≤ VDD.
6 W3 Wiper Terminal of RDAC3. VSS ≤ VW ≤ VDD.
7 B3 Terminal B of RDAC3. VSS ≤ VB ≤ VDD.
8 VSS Negative Power Supply. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
9 A2 Terminal A of RDAC2. VSS ≤ VA ≤ VDD.
10 W2 Wiper Terminal of RDAC2. VSS ≤ VW ≤ VDD.
11 B2 Terminal B of RDAC2. VSS ≤ VB ≤ VDD.
12 A4 Terminal A of RDAC4. VSS ≤ VA ≤ VDD.
13 W4 Wiper Terminal of RDAC4. VSS ≤ VW ≤ VDD.
14 B4 Terminal B of RDAC4. VSS ≤ VB ≤ VDD.
15 VDD Positive Power Supply. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
16 VLOGIC Logic Power Supply; 1.8 V to VDD. Decouple this pin with 0.1 µF ceramic capacitors and 10 µF capacitors.
17
SCL/SCLK
I
2
C Serial Clock Line (SCL). Data is clocked in at the logic low transition.
SPI Serial Clock Line (SCLK). Data is clocked in at the logic low transition.
18 DIS Digital Interface Select (SPI/I2C Select). SPI when DIS = 0 (GND), and I2C when DIS = 1 (VLOGIC). This pin cannot be
left floating.
19 SDA/SDI Serial Data Input/Output (SDA), When DIS = 1.
Serial Data Input (SDI), When DIS = 0.
20 WP Optional Write Protect. This pin prevents any changes to the present RDAC and EEPROM content, except when
reloading the content of the EEPROM into the RDAC register. WP is activated at logic low. If this pin is not used,
tie WP to VLOGIC.
21 ADDR1/SDO Programmable Address (ADDR1) for Multiple Package Decoding, When DIS = 1.
Serial Data Output (SDO). Open-drain output, needs an external pull-up resistor, when DIS = 0.
22 ADDR0/SYNC Programmable Address (ADDR0) for Multiple Package Decoding, When DIS = 1.
Synchronization Data Input, When DIS = 0. This pin is active low. When SYNC returns high, data is loaded into
the input shift register.
23 LRDAC Load RDAC. Transfers the contents of the input registers to their respective RDAC registers when their
associated input registers were previously loaded using Command 2 (see Table 20). This allows simultaneous
update of all RDAC registers. LRDAC is activated at the high-to-low transition. If not used, tie LRDAC to VLOGIC.
24 RESET Hardware Reset Pin. Refresh the RDAC registers from EEPROM. RESET is activated at the logic low. If not used,
tie RESET to VLOGIC.
EPAD Internally Connect the Exposed Pad to VSS.
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 17 of 36
TYPICAL PERFORMANCE CHARACTERISTICS
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
0.4
0.5
0100 200
R-INL (LSB)
CODE ( Decimal)
10kΩ, +125°C
10kΩ, + 25°C
10kΩ, –40°C
100kΩ, +125°C
100kΩ, +25°C
100kΩ, –40°C
10877-012
Figure 12. R-INL vs. Code (AD5144/AD5144A)
R-INL (LSB)
CODE ( Decimal)
–0.25
–0.20
–0.15
–0.10
–0.05
0
0.05
0.10
0.15
0.20
050 100
10kΩ, +125°C
10kΩ, +25°C
10kΩ, –40°C
100kΩ, +125°C
100kΩ, +25°C
100kΩ, –40°C
10877-013
Figure 13. R-INL vs. Code (AD5124)
0100 200
–0.3
–0.2
–0.1
0
0.1
0.2
0.3
INL (LSB)
CODE ( Decimal)
10kΩ, –40°C
10kΩ, +25°C
10kΩ, +125°C
100kΩ, –40°C
100kΩ, +25°C
100kΩ, +125°C
10877-014
Figure 14. INL vs. Code (AD5144/AD5144A)
–0.6
–0.5
–0.4
–0.3
–0.2
–0.1
0
0.1
0.2
0100 200
R-DNL (LSB)
10877-015
CODE ( Decimal)
10kΩ, +125°C
10kΩ, +25°C
10kΩ, –40°C
100kΩ, +125°C
100kΩ, +25°C
100kΩ, –40°C
Figure 15. R-DNL vs. Code (AD5144/AD5144A)
CODE ( Decimal)
–0.30
–0.25
–0.20
–0.15
–0.10
–0.05
0
0.05
0.10
050 100
R-DNL (LSB)
10877-016
10kΩ, +125°C
10kΩ, +25°C
10kΩ, –40°C
100kΩ, +125°C
100kΩ, +25°C
100kΩ, –40°C
Figure 16. R-DNL vs. Code (AD5124)
–0.30
–0.25
–0.20
–0.15
–0.10
–0.05
0
0.05
0.10
DNL (LSB)
CODE ( Decimal)
10kΩ, –40°C
10kΩ, +25°C
10kΩ, +125°C
100kΩ, –40°C
100kΩ, +25°C
100kΩ, +125°C
10877-017
0100 200
Figure 17. DNL vs. Code (AD5144/AD5144A)
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 18 of 36
–0.15
–0.10
–0.05
0
0.05
0.10
0.15
050 100
INL (LSB)
CODE ( Decimal)
10877-018
10kΩ, –40°C
10kΩ, +25°C
10kΩ, +125°C
100kΩ, –40°C
100kΩ, +25°C
100kΩ, +125°C
Figure 18. INL vs. Code (AD5124)
10877-019
–50
0
50
100
150
200
250
300
350
400
450
POTENTI O MET ER MODE TEMPERATURE
COEFFICIENT (ppm/°C)
CODE ( Decimal)
100kΩ
10kΩ
0 50 100150200255
0 25 50 75 100127
AD5124
AD5144/
AD5144A
Figure 19. Potentiometer Mode Temperature Coefficient ((ΔVW/VW)/ΔT × 106)
vs. Code
0
100
200
300
400
500
600
700
800
–40 10 60 125110
CURRENT (n A)
TEMPERATURE (°C)
10877-020
I
DD
, V
DD
= 2.3V
I
DD
, V
DD
= 3.3V
I
DD
, V
DD
= 5V
I
LOGIC
, V
LOGIC
= 2.3V
I
LOGIC
, V
LOGIC
= 3.3V
I
LOGIC
, V
LOGIC
= 5V
V
DD
= V
LOGIC
V
SS
= GND
Figure 20. Supply Current vs. Temperature
–0.14
–0.12
–0.10
–0.08
–0.06
–0.04
–0.02
0
0.02
0.04
0.06
050 100
DNL (LSB)
CODE (Deci mal)
10877-021
10kΩ, –40°C
10kΩ, +25°C
10kΩ, +125°C
100kΩ, –40°C
100kΩ, +25°C
100kΩ, +125°C
Figure 21. DNL vs. Code (AD5124)
AD5124
AD5144/
AD5144A
–50
0
50
100
150
200
250
300
350
400
450
RHEOSTAT MODE TEMPERATURE
COEFFICIENT (ppm/°C)
10kΩ
100kΩ
10877-122
CODE ( Decimal)
0 50 100150200255
0 25 50 75 100127
Figure 22. Rheostat Mode Temperature Coefficient ((ΔRWB/RWB)/ΔT × 106)
vs. Code
0
200
400
600
800
1000
1200
012345
I
LOGIC
CURRENT (µA)
INPUT VOLATGE (V)
10877-023
I
2
C, V
LOGIC
= 1.8V
I
2
C, V
LOGIC
= 2.3V
I
2
C, V
LOGIC
= 3.3V
I
2
C, V
LOGIC
= 5V
I
2
C, V
LOGIC
= 5.5V
SPI, V
LOGIC
= 1.8V
SPI, V
LOGIC
= 2.3V
SPI, V
LOGIC
= 3.3V
SPI, V
LOGIC
= 5V
SPI, V
LOGIC
= 5.5V
Figure 23. ILOGIC Current vs. Digital Input Voltage
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 19 of 36
–60
–50
–40
–30
–20
–10
0
10 100 1k 10k 100k 1M 10M
GAIN (d B)
FREQUENCY (Hz)
AD5144/AD5144A (AD5124)
10877-022
0x80 (0x40)
0x40 (0x20)
0x20 (0x10)
0x10 (0x08)
0x8 (0x04)
0x4 (0x02)
0x2 (0x01)
0x1 (0x00)
0x00
Figure 24. 10 kΩ Gain vs. Frequency vs. Code
–100
–90
–80
–70
–60
–50
–40
20 200 2k 20k 200k
THD + N ( dB)
FREQUENCY (Hz)
10kΩ
100kΩ
10877-025
V
DD
/V
SS
= ±2. 5V
V
A
= 1V rms
V
B
= GND
CODE = HALF S CALE
NOISE FI LTE R = 22kHz
Figure 25. Total Harmonic Distortion Plus Noise (THD + N) vs. Frequency
–100
–80
–60
–40
–20
0
20
10 100 1k 10k 100k 1M 10M
PHASE (Degrees)
FREQUENCY (Hz)
10877-026
QUARTER SCALE
MIDSCALE
FULL-SCALE
VDD/VSS = ± 2.5V
RAB = 10kΩ
Figure 26. Normalized Phase Flatness vs. Frequency, RAB = 10 kΩ
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
GAIN (d B)
FREQUENCY (Hz)
10 100 1k 10k 100k 1M 10M
10877-123
0x80 (0x40)
0x40 (0x20)
0x20 (0x10)
0x10 (0x08)
0x8 (0x04)
0x4 (0x02)
0x2 (0x01)
0x1 (0x00)
0x00
AD5144/AD5144A (AD5124)
Figure 27. 100 kΩ Gain vs. Frequency vs. Code
10kΩ
100kΩ
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
0.001 0.01 0.1 1
THD + N ( dB)
VOLTAGE ( V rms)
V
DD
/V
SS
= ±2. 5V
f
IN
= 1kHz
CODE = HALF S CALE
NOISE FILTER = 22kHz
10877-028
Figure 28. Total Harmonic Distortion Plus Noise (THD + N) vs. Amplitude
–80
–90
–70
–60
–50
–40
–30
–20
–10
0
10
10 100 1k 10k 100k 1M
PHASE (Degrees)
FREQUENCY (Hz)
QUARTER SCALE
MIDSCALE
FULL-SCALE
10877-029
V
DD
/V
SS
= ±2. 5V
R
AB
= 100kΩ
Figure 29. Normalized Phase Flatness vs. Frequency, RAB = 100 kΩ
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 20 of 36
0
100
200
300
400
500
600
01234 5
WIPER ON RESISTANCE (Ω)
VOLTAGE (V)
100kΩ, V
DD
= 2.3V
100kΩ, V
DD
= 2.7V
100kΩ, V
DD
= 3V
100kΩ, V
DD
= 3.6V
100kΩ, V
DD
= 5V
100kΩ, V
DD
= 5.5V
10kΩ, V
DD
= 2.3V
10kΩ, V
DD
= 2.7V
10kΩ, V
DD
= 3V
10kΩ, V
DD
= 3.6V
10kΩ, V
DD
= 5V
10kΩ, V
DD
= 5.5V
10877-030
Figure 30. Incremental Wiper On Resistance vs. Positive Power Supply (VDD)
10877-031
0
1
2
3
4
5
6
7
8
9
10
020 40 60 80 100 120
010 20 30 40 50 60
BANDWIDTH ( M Hz )
CODE ( Decimal)
AD5144/
AD5144A
AD5124
10kΩ + 0pF
10kΩ + 75pF
10kΩ + 150pF
10kΩ + 250pF
100kΩ + 0p F
100kΩ + 75p F
100kΩ + 150p F
100kΩ + 250p F
Figure 31. Maximum Bandwidth vs. Code vs. Net Capacitance
–0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 5 10 15
RELAT I VE VOLTAGE (V)
TIME (µs)
0x80 TO 0x7F, 100kΩ
0x80 TO 0x7F, 10kΩ
10877-032
V
DD
/V
SS
= ±2. 5V
V
A
= V
DD
V
B
= V
SS
Figure 32. Maximum Transition Glitch
0
0.2
0.4
0.6
0.8
1.0
1.2
0
0.0005
0.0010
0.0015
0.0020
0.0025
–400–500–600–300–200–100 0 100200 300 400500600
CUMULATIVE PROBABILITY
PROBABILITY DENSITY
RESISTOR DRIFT (ppm)
10877-033
Figure 33. Resistor Lifetime Drift
–90
–80
–70
–60
–50
–40
–30
–20
–10
0
10 100 1k 10k 100k 1M 10M
PSRR ( dB)
FREQUENCY (Hz)
10kΩ
100kΩ
10877-034
V
DD
= 5V ±10% AC
V
SS
= GND, V
A
= 4V, V
B
= GND
CODE = M IDSCALE
Figure 34. Power Supply Rejection Ratio (PSRR) vs. Frequency
–0.020
–0.015
–0.010
–0.005
0
0.005
0.010
0.015
0.020
0500 1000 1500 2000
RELAT I VE VOLTAGE (V)
TIME (n s)
10877-035
VDD/VSS = ± 2.5V
VA = VDD
VB = VSS
CODE = HALF S CALE
Figure 35. Digital Feedthrough
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 21 of 36
–120
–100
–80
–60
–40
–20
0
10 100 1k 10k 100k 1M 10M
GAIN (d B)
FREQUENCY (Hz)
10kΩ
100kΩ
10877-036
SHUT DOWN M ODE E NABLED
Figure 36. Shutdown Isolation vs. Frequency
0
1
2
3
4
5
6
7
050 100 150 200 250
025 50 75 100 125
AD5124
THEORETICAL I
MAX
(mA)
AD5144/
AD5144A
100kΩ
10kΩ
CODE ( Decimal)
10877-037
Figure 37. Theoretical Maximum Current vs. Code
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 22 of 36
TEST CIRCUITS
Figure 38 to Figure 42 define the test conditions used in the Specifications section.
A
W
B
NC
I
W
DUT
V
MS
NC = NO CONNECT
10877-038
Figure 38. Resistor Integral Nonlinearity Error (Rheostat Operation; R-INL, R-DNL)
A
W
B
DUT
V
MS
V+
V+ = V
DD
1LSB = V+/2
N
10877-039
Figure 39. Potentiometer Divider Nonlinearity Error (INL, DNL)
A
W
NC
B
DUT I
W
= V
DD
/R
NOMINAL
V
MS1
V
W
R
W
= V
MS1
/I
W
10877-040
NC = NO CONNECT
Figure 40. Wiper Resistance
AW
BV
MS
V+ = V
DD
±10%
PSRR (dB) = 20 LOG
V
MS
∆V
DD
()
~
V
A
V
DD
∆V
MS%
∆V
DD%
PSS (%/%) =
V+
∆
10877-041
Figure 41. Power Supply Sensitivity and
Power Supply Rejection Ratio (PSS and PSRR)
+
–
DUT
CODE = 0x00
0.1V
V
SS
TO V
DD
R
SW
=0.1
V
I
SW
I
SW
W
B
A = NC
10877-045
Figure 42. Incremental On Resistance
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 23 of 36
THEORY OF OPERATION
The AD5124/AD5144/AD5144A digital programmable
potentiometers are designed to operate as true variable resistors
for analog signals within the terminal voltage range of VSS < VTERM <
VDD. The resistor wiper position is determined by the RDAC
register contents. The RDAC register acts as a scratchpad register
that allows unlimited changes of resistance settings. A secondary
register (the input register) can be used to preload the RDAC
register data.
The RDAC register can be programmed with any position setting
using the I2C or SPI interface (depending on the model). When
a desirable wiper position is found, this value can be stored in
the EEPROM memory. Thereafter, the wiper position is always
restored to that position for subsequent power-ups. The storing
of the EEPROM data takes approximately 15 ms; during this
time, the device is locked and does not acknowledge any new
command, preventing any changes from taking place.
RDAC REGISTER AND EEPROM
The RDAC register directly controls the position of the digital
potentiometer wiper. For example, when the RDAC register is
loaded with 0x80 (AD5144/AD5144A, 256 taps), the wiper is
connected to half scale of the variable resistor. The RDAC register
is a standard logic register; there is no restriction on the number
of changes allowed.
It is possible to both write to and read from the RDAC register
using the digital interface (see Table 14).
The contents of the RDAC register can be stored to the EEPROM
using Command 9 (see Table 14). Thereafter, the RDAC register
always sets at that position for any future on-off-on power
supply sequence. It is possible to read back data saved into the
EEPROM with Command 3 (see Table 14).
Alternatively, the EEPROM can be written to independently
using Command 11 (see Table 20).
INPUT SHIFT REGISTER
For the AD5124/AD5144/AD5144A, the input shift register is
16 bits wide, as shown in Figure 4. The 16-bit word consists of
four control bits, followed by four address bits and by eight
data bits.
If the AD5124 RDAC or EEPROM registers are read from or
written to, the lowest data bit (Bit 0) is ignored.
Data is loaded MSB first (Bit 15). The four control bits determine
the function of the software command, as listed in Table 14 and
Table 20.
SERIAL DATA DIGITAL INTERFACE SELECTION, DIS
The AD5124/AD5144 LFSCP provides the flexibility of a selectable
interface. When the digital interface select (DIS) pin is tied low,
the SPI mode is engaged. When the DIS pin is tied high, the I2C
mode is engaged.
SPI SERIAL DATA INTERFACE
The AD5124/AD5144 contain a 4-wire, SPI-compatible digital
interface (SDI, SYNC, SDO, and SCLK). The write sequence
begins by bringing the SYNC line low. The SYNC pin must be
held low until the complete data-word is loaded from the SDI
pin. Data is loaded in at the SCLK falling edge transition, as
shown in Figure 6. When SYNC returns high, the serial data-
word is decoded according to the instructions in Table 20.
To minimize power consumption in the digital input buffers
when the part is enabled, operate all serial interface pins close
to the VLOGIC supply rails.
SYNC Interruption
In a standalone write sequence for the AD5124/AD5144,
the SYNC line is kept low for 16 falling edges of SCLK, and the
instruction is decoded when SYNC is pulled high. However, if
the SYNC line is kept low for less than 16 falling edges of SCLK,
the input shift register content is ignored, and the write sequence is
considered invalid.
SDO Pin
The serial data output pin (SDO) serves two purposes: to read back
the contents of the control, EEPROM, RDAC, and input registers
using Command 3 (see Table 14 and Table 20), and to connect the
AD5124/AD5144 in daisy-chain mode.
The SDO pin contains an internal open-drain output that needs an
external pull-up resistor. The SDO pin is enabled when SYNC is
pulled low, and the data is clocked out of SDO on the rising
edge of SCLK, as shown in Figure 6 and Figure 7.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 24 of 36
Daisy-Chain Connection
Daisy chaining minimizes the number of port pins required from
the controlling IC. As shown in Figure 43, the SDO pin of one
package must be tied to the SDI pin of the next package. The clock
period may need to be increased because of the propagation
delay of the line between subsequent devices. When two AD5124/
AD5144 devices are daisy chained, 32 bits of data are required.
The first 16 bits are assigned to U2, and the second 16 bits are
assigned to U1, as shown in Figure 44. Keep the SYNC pin low
until all 32 bits are clocked into their respective serial registers.
The SYNC pin is then pulled high to complete the operation.
To prevent data from mislocking (for example, due to noise) the
part includes an internal counter, if the SCLK falling edges count is
not a multiple of 8, the part ignores the command. A valid clock
count is 16, 24, 32, 40, and so on. The counter resets when SYNC
returns high.
MOSI
SSSCLKMISO
MICROCONTROLLER
SDI SDO
SCLK SCLK
R
P
2.2kΩ
R
P
2.2kΩ
SDI SDO
U1 U2
AD5124/
AD5144
AD5124/
AD5144
SYNC
V
LOGIC
SYNC
DAISY-CHAIN
V
LOGIC
10877-046
Figure 43. Daisy-Chain Configuration
DB15
SCLK
SYNC
MOSI
12 16
DB0
DB15
SDO_U1
32
DB15
DB0 DB15
DB0
17 18
DB0
INPUT WORD FOR U2 INPUT WORD FOR U1
INPUT WORD FOR U2
UNDEFINED
10877-047
Figure 44. Daisy-Chain Diagram
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 25 of 36
I2C SERIAL DATA INTERFACE
The AD5144/AD5144A have 2-wire, I2C-compatible serial
interfaces. These devices can be connected to an I2C bus as a
slave device, under the control of a master device. See Figure 5
for a timing diagram of a typical write sequence.
The AD5144/AD5144A support standard (100 kHz) and fast
(400 kHz) data transfer modes. Support is not provided for
10-bit addressing and general call addressing.
The 2-wire serial bus protocol operates as follows:
1. The master initiates a data transfer by establishing a start
condition, which is when a high-to-low transition on the
SDA line occurs while SCL is high. The following byte is
the address byte, which consists of the 7-bit slave address
and an R/W bit. The slave device corresponding to the
transmitted address responds by pulling SDA low during
the ninth clock pulse (this is called the acknowledge bit).
At this stage, all other devices on the bus remain idle while
the selected device waits for data to be written to, or read
from, its shift register.
If the R/W bit is set high, the master reads from the slave
device. However, if the R/W bit is set low, the master writes
to the slave device.
2. Data is transmitted over the serial bus in sequences of nine
clock pulses (eight data bits followed by an acknowledge bit).
The transitions on the SDA line must occur during the low
period of SCL and remain stable during the high period of SCL.
3. When all data bits have been read from or written to, a stop
condition is established. In write mode, the master pulls the
SDA line high during the tenth clock pulse to establish a stop
condition. In read mode, the master issues a no acknowledge
for the ninth clock pulse (that is, the SDA line remains high).
The master then brings the SDA line low before the tenth
clock pulse, and then high again during the tenth clock pulse
to establish a stop condition.
I2C ADDRESS
The AD5144/AD5144A each have two different device address
options available (see Table 12 and Table 13).
Table 12. 20-Lead TSSOP Device Address Selection
ADDR 7-Bit I2C Device Address
VLOGIC 0101000
No connect1 0101010
GND 0101011
1 Not available in bipolar mode (VSS < 0 V) or in low voltage mode (VLOGIC = 1.8 V).
Table 13. 24-Lead LFCSP Device Address Selection
ADDR0 Pin ADDR1 Pin 7-Bit I2C Device Address
VLOGIC VLOGIC 0100000
No connect1 VLOGIC 0100010
GND VLOGIC 0100011
VLOGIC No connect1 0101000
No connect1 No connect1 0101010
GND No connect1 0101011
VLOGIC GND 0101100
No connect1 GND 0101110
GND GND 0101111
1 Not available in bipolar mode (VSS < 0 V) or in low voltage mode (VLOGIC = 1.8 V).
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 26 of 36
Table 14. Reduced Commands Operation Truth Table
Command
Number
Control
Bits[DB15:DB12]
Address
Bits[DB11:DB8]1 Data Bits[DB7:DB0] 1
C3 C2 C1 C0 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Operation
0 0 0 0 0 X X X X X X X X X X X X NOP: do nothing.
1 0 0 0 1 0 0 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Write contents of serial register
data to RDAC
2 0 0 1 0 0 0 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Write contents of serial register
data to input register
3
0
0
1
1
X
0
A1
A0
X
X
X
X
X
X
D1
D0
Read back contents
D1 D0 Data
0 1 EEPROM
1 1 RDAC
9 0 1 1 1 0 0 A1 A0 X X X X X X X 1 Copy RDAC register to EEPROM
10
0
1
1
1
0
0
A1
A0
X
X
X
X
X
X
X
0
Copy EEPROM into RDAC
14 1 0 1 1 X X X X X X X X X X X X Software reset
15 1 1 0 0 A3 0 A1 A0 X X X X X X X D0 Software shutdown
D0
Condition
0 Normal mode
1
Shutdown mode
1 X = don’t care.
Table 15. Reduced Address Bits Table
A3 A2 A1 A0 Channel Stored Channel Memory
1 0 X1 X1 All channels Not applicable
0 0 0 0 RDAC1 RDAC1
0 0 0 1 RDAC2 RDAC2
0 0 1 0 RDAC3 RDAC3
0 0 1 1 RDAC4 RDAC4
1 X = don’t care.
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 27 of 36
ADVANCED CONTROL MODES
The AD5124/AD5144/AD5144A digital potentiometers include
a set of user programming features to address the wide number of
applications for these universal adjustment devices (see Table 20
and Table 22).
Key programming features include the following:
• Input register
• Linear gain setting mode
• Low wiper resistance feature
• Linear increment and decrement instructions
• ±6 dB increment and decrement instructions
• Burst mode (I2C only)
• Reset
• Shutdown mode
Input Register
The AD5124/AD5144/AD5144A include one input register per
RDAC register. These registers allow preloading of the value for
the associated RDAC register. These registers can be written to
using Command 2 and read back from using Command 3 (see
Table 20).
This feature allows a synchronous and asynchronous update of
one or all of the RDAC registers at the same time.
The transfer from the input register to the RDAC register is
done asynchronously by the LRDAC pin or synchronously by
Command 8 (see Table 20).
If new data is loaded into an RDAC register, this RDAC register
automatically overwrites the associated input register.
Linear Gain Setting Mode
The patented architecture of the AD5124/AD5144/AD5144A
allows the independent control of each string resistor, RAW, and
RWB. To enable this feature, use Command 16 (see Table 20) to set
Bit D2 of the control register (see Table 22).
This mode of operation can control the potentiometer as two
independent rheostats connected at a single point, the W terminal.
This feature enables a second input and an RDAC register per
channel, as shown in Table 21, but the actual RDAC contents remain
unchanged. The same operations are valid for potentiometer and
linear gain setting modes. The EEPROM commands affect the
RWB resistance only. The parts restores in potentiometer mode
after a reset or power-up.
Low Wiper Resistance Feature
The AD5124/AD5144/AD5144A include two commands to
reduce the wiper resistance between the terminals when the
devices achieve full scale or zero scale. These extra positions are
called bottom scale, BS, and top scale, TS. The resistance between
Terminal A and Terminal W at top scale is specified as RTS.
Similarly, the bottom scale resistance between Terminal B and
Terminal W is specified as RBS.
The contents of the RDAC registers are unchanged by entering
into these positions. There are three ways to exit from top scale
and bottom scale: by using Command 12 or Command 13
(see Table 20); by loading new data in an RDAC register, which
includes increment/decrement operations; or by entering
shutdown mode, Command 15 (see Table 20).
Table 16 and Table 17 show the truth tables for the top scale
position and the bottom scale position, respectively, when the
potentiometer or linear gain setting mode is enabled.
Table 16. Top Scale Truth Table
Linear Gain Setting Mode
Potentiometer Mode
RAW RWB RAW RWB
RAB RAB RTS RAB
Table 17. Bottom Scale Truth Table
Linear Gain Setting Mode Potentiometer Mode
RAW RWB RAW RWB
RTS RBS RAB RBS
Linear Increment and Decrement Instructions
The increment and decrement commands (Command 4 and
Command 5 in Table 20) are useful for linear step adjustment
applications. These commands simplify microcontroller software
coding by allowing the controller to send an increment or
decrement command to the device. The adjustment can be
individual or in a ganged potentiometer arrangement, where
all wiper positions are changed at the same time.
For an increment command, executing Command 4 automatically
moves the wiper to the next RDAC position. This command
can be executed in a single channel or multiple channels.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 28 of 36
±6 dB Increment and Decrement Instructions
Two programming instructions produce logarithmic taper
increment or decrement of the wiper position control by
an individual potentiometer or by a ganged potentiometer
arrangement where all RDAC register positions are changed
simultaneously. The +6 dB increment is activated by Command 6,
and the −6 dB decrement is activated by Command 7 (see Table 20).
For example, starting with the zero-scale position and executing
Command 6 ten times moves the wiper in 6 dB steps to the full-
scale position. When the wiper position is near the maximum
setting, the last 6 dB increment instruction causes the wiper to go
to the full-scale position (see Table 18).
Incrementing the wiper position by +6 dB essentially doubles the
RDAC register value, whereas decrementing the wiper position
by −6 dB halves the register value. Internally, the AD5124/
AD5144/AD5144A use shift registers to shift the bits left and
right to achieve a ±6 dB increment or decrement. These functions
are useful for various audio/video level adjustments, especially
for white LED brightness settings in which human visual responses
are more sensitive to large adjustments than to small adjustments.
Table 18. Detailed Left Shift and Right Shift Functions for
the ±6 dB Step Increment and Decrement
Left Shift (+6 dB/Step) Right Shift (−6 dB/Step)
0000 0000 1111 1111
0000 0001 0111 1111
0000 0010 0011 1111
0000 0100
0001 1111
0000 1000 0000 1111
0001 0000 0000 0111
0010 0000 0000 0011
0100 0000 0000 0001
1000 0000 0000 0000
1111 1111 0000 0000
Burst Mode (I2C Only)
By enabling the burst mode, multiple data bytes can be sent to
the part consecutively. After the command byte, the part interprets
the following consecutive bytes as data bytes for the command.
A new command can be sent by generating a repeat start or by a
stop and start condition.
The burst mode is activated by setting Bit D3 of the control
register (see Table 22).
Reset
The AD5124/AD5144/AD5144A can be reset through software
by executing Command 14 (see Table 20) or through hardware
on the low pulse of the RESET pin. The reset command loads the
RDAC register with the contents of the EEPROM and takes
approximately 30 µs. The EEPROM is preloaded to midscale at
the factory, and initial power-up is, accordingly, at midscale.
Tie RESET to VDD if the RESET pin is not used.
Shutdown Mode
The AD5124/AD5144/AD5144A can be placed in shutdown mode
by executing the software shutdown command, Command 15
(see Table 20), and setting the LSB (D0) to 1. This feature places
the RDAC in a zero power consumption state where the device
operates in potentiometer mode, Terminal A is open circuited,
and the wiper, Terminal W, is connected to Terminal B; however, a
finite wiper resistance of 40 Ω is present. When the device is
configured in linear gain setting mode, the resistor addressed,
RAW or RWB, is internally place at high impedance. Table 19 shows a
truth table depending on the device operating mode. The contents
of the RDAC register are unchanged by entering shutdown mode.
However, all commands listed in Table 20 are supported while
in shutdown mode. Execute Command 15 (see Table 20) and set
the LSB (D0) to 0 to exit shutdown mode.
Table 19. Shutdown Mode Truth Table
Linear Gain Setting Mode Potentiometer Mode
RAW RWB RAW RWB
High impedance High impedance High impedance RBS
EEPROM OR RDAC REGISTER PROTECTION
The EEPROM and RDAC registers can be protected by disabling
any update to these registers. This can be done by using software or
by using hardware. If these registers are protected by software,
set Bit D0 and/or Bit D1 (see Table 22), which protects the RDAC
and EEPROM registers independently.
If the registers are protected by hardware, pull the WP pin low
(only available in the LFCSP package). If the WP pin is pulled
low when the part is executing a command, the protection is not
enabled until the command is completed (only available in the
LFCSP package).
When RDAC is protected, the only operation allowed is to copy
the EEPROM into the RDAC register.
LOAD RDAC INPUT REGISTER (LRDAC)
LRDAC software or hardware transfers data from the input
register to the RDAC register (and therefore updates the wiper
position). By default, the input register has the same value as the
RDAC register; therefore, only the input register that has been
updated using Command 2 is updated.
Software LRDAC, Command 8, allows updating of a single RDAC
register or all of the channels at once (see Table 20). This is a
synchronous update.
The hardware LRDAC is completely asynchronous and copies
the content of all the input registers into the associated RDAC
registers. If a command is being executed, any transition in
the LRDAC pin is ignored by the part to avoid data corruption.
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 29 of 36
Table 20. Advance Commands Operation Truth Table
Command
Number
Control
Bits[DB15:DB12]
Address
Bits[DB11:DB8]1 Data Bits[DB7:DB0]1
C3 C2 C1 C0 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Operation
0 0 0 0 0 X X X X X X X X X X X X NOP: do nothing
1 0 0 0 1 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Write contents of serial
register data to RDAC
2 0 0 1 0 A3 A2 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Write contents of serial
register data to input
register
3 0 0 1 1 X A2 A1 A0 X X X X X X D1 D0 Read back contents
D1 D0 Data
0 0 Input register
0 1 EEPROM
1 0 Control
register
1 1 RDAC
4
0
1
0
0
A3
A2
A1
A0
X
X
X
X
X
X
X
1
Linear RDAC increment
5 0 1 0 0 A3 A2 A1 A0 X X X X X X X 0 Linear RDAC decrement
6 0 1 0 1 A3 A2 A1 A0 X X X X X X X 1 +6 dB RDAC increment
7 0 1 0 1 A3 A2 A1 A0 X X X X X X X 0 −6 dB RDAC decrement
8 0 1 1 0 A3 A2 A1 A0 X X X X X X X X Copy input register to RDAC
(software LRDAC)
9 0 1 1 1 0 0 A1 A0 X X X X X X X 1 Copy RDAC register to
EEPROM
10 0 1 1 1 0 0 A1 A0 X X X X X X X 0 Copy EEPROM into RDAC
11 1 0 0 0 0 0 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 Write contents of serial
register data to EEPROM
12
1
0
0
1
A3
A2
A1
A0
1
X
X
X
X
X
X
D0
Top scale
D0 = 0; normal mode
D0 = 1; shutdown mode
13
1
0
0
1
A3
A2
A1
A0
0
X
X
X
X
X
X
D0
Bottom scale
D0 = 1; enter
D0 = 0; exit
14 1 0 1 1 X X X X X X X X X X X X Software reset
15 1 1 0 0 A3 A2 A1 A0 X X X X X X X D0 Software shutdown
D0 = 0; normal mode
D0 = 1; device placed in
shutdown mode
16 1 1 0 1 X X X X X X X X D3 D2 D1 D0 Copy serial register data to
control register
1 X = don’t care.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 30 of 36
Table 21. Address Bits
A3 A2 A1 A0
Potentiometer Mode Linear Gain Setting Mode Stored RDAC
Memory Input Register RDAC Register Input Register RDAC Register
1 X1 X1 X1 All channels All channels All channels All channels Not applicable
0 0 0 0 RDAC1 RDAC1 RWB1 RWB1 RDAC1
0 1 0 0 Not applicable Not applicable RAW1 RAW1 Not applicable
0 0 0 1 RDAC2 RDAC2 RWB2 RWB2 RDAC2
0 1 0 1 Not applicable Not applicable RAW2 RAW2 Not applicable
0 0 1 0 RDAC3 RDAC3 RWB3 RWB3 RDAC3
0 1 1 0 Not applicable Not applicable RAW3 RAW3 Not applicable
0 0 1 1 RDAC4 RDAC4 RWB4 RWB4 RDAC4
0 1 1 1 Not applicable Not applicable RAW4 RAW4 Not applicable
1 X = don’t care.
Table 22. Control Register Bit Descriptions
Bit Name Description
D0 RDAC register write protect
0 = wiper position frozen to value in EEPROM memory
1 = allows update of wiper position through digital interface (default)
D1 EEPROM program enable
0 = EEPROM program disabled
1 = enables device for EEPROM program (default)
D2 Linear setting mode/potentiometer mode
0 = potentiometer mode (default)
1 = linear gain setting mode
D3 Burst mode (I2C only)
0 = disabled (default)
1 = enabled (no disable after stop or repeat start condition)
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 31 of 36
RDAC ARCHITECTURE
To achieve optimum performance, Analog Devices, Inc., has
patented the RDAC segmentation architecture for all the digital
potentiometers. In particular, the AD5124/AD5144 employ a
three-stage segmentation approach, as shown in Figure 45. The
AD5124/AD5144/AD5144A wiper switch is designed with the
transmission gate CMOS topology and with the gate voltage
derived from VDD and VSS.
7-BIT/8-BIT
ADDRESS
DECODER
R
L
W
R
L
A
R
H
R
H
R
M
R
M
B
R
M
R
M
R
H
R
H
S
TS
S
BS
10877-048
Figure 45. AD5124/AD5144/AD5144A Simplified RDAC Circuit
Top Scale/Bottom Scale Architecture
In addition, the AD5124/AD5144/AD5144A include new
positions to reduce the resistance between terminals. These
positions are called bottom scale and top scale. At bottom scale,
the typical wiper resistance decreases from 130 Ω to 60 Ω (RAB =
100 kΩ). At top scale, the resistance between Terminal A and
Terminal W is decreased by 1 LSB, and the total resistance is
reduced to 60 Ω (RAB = 100 kΩ).
PROGRAMMING THE VARIABLE RESISTOR
Rheostat Operation—±8% Resistor Tolerance
The AD5124/AD5144/AD5144A operate in rheostat mode when
only two terminals are used as a variable resistor. The unused
terminal can be floating, or it can be tied to Terminal W, as shown
in Figure 46.
A
W
B
A
W
B
A
W
B
10877-049
Figure 46. Rheostat Mode Configuration
The nominal resistance between Terminal A and Terminal B,
RAB, is 10 k or 100 k, and has 128/256 tap points accessed by
the wiper terminal. The 7-bit/8-bit data in the RDAC latch is
decoded to select one of the 128/256 possible wiper settings. The
general equations for determining the digitally programmed
output resistance between Terminal W and Terminal B are
AD5124:
W
AB
WB RR
D
DR
128
)( From 0x00 to 0x7F (1)
AD5144/AD5144A:
W
AB
WB RR
D
DR
256
)( From 0x00 to 0xFF (2)
where:
D is the decimal equivalent of the binary code in the 7-bit/8-bit
RDAC register.
RAB is the end-to-end resistance.
RW is the wiper resistance.
In potentiometer mode, similar to the mechanical potentiometer,
the resistance between Terminal W and Terminal A also produces
a digitally controlled complementary resistance, RWA . RWA also
gives a maximum of 8% absolute resistance error. RWA starts at the
maximum resistance value and decreases as the data loaded into
the latch increases. The general equations for this operation are
AD5124:
W
ABAW RR
D
DR
128
128
)( From 0x00 to 0x7F (3)
AD5144/AD5144A:
W
ABAW RR
D
DR
256
256
)( From 0x00 to 0xFF (4)
where:
D is the decimal equivalent of the binary code in the 7-bit/8-bit
RDAC register.
RAB is the end-to-end resistance.
RW is the wiper resistance.
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 32 of 36
If the part is configured in linear gain setting mode, the resistance
between Terminal W and Terminal A is directly proportional
to the code loaded in the associate RDAC register. The general
equations for this operation are
AD5124:
W
AB
WB RR
D
DR
128
)( From 0x00 to 0x7F (5)
AD5144/AD5144A:
W
AB
WB RR
D
DR
256
)( From 0x00 to 0xFF (6)
where:
D is the decimal equivalent of the binary code in the 7-bit/8-bit
RDAC register.
RAB is the end-to-end resistance.
RW is the wiper resistance.
In the bottom scale condition or top scale condition, a finite
total wiper resistance of 40 Ω is present. Regardless of which
setting the part is operating in, limit the current between
Terminal A to Terminal B, Terminal W to Terminal A, and
Terminal W to Terminal B to the maximum continuous
current of ±6 mA or to the pulse current specified in Table 7.
Otherwise, degradation or possible destruction of the internal
switch contact can occur.
PROGRAMMING THE POTENTIOMETER DIVIDER
Voltage Output Operation
The digital potentiometer easily generates a voltage divider at
wiper-to-B and wiper-to-A that is proportional to the input voltage
at A to B, as shown in Figure 47.
W
A
B
V
A
V
OUT
V
B
10877-050
Figure 47. Potentiometer Mode Configuration
Connecting Terminal A to 5 V and Terminal B to ground
produces an output voltage at the Wiper W to Terminal B
ranging from 0 V to 5 V. The general equation defining the
output voltage at VW with respect to ground for any valid
input voltage applied to Terminal A and Terminal B is
B
AB
AW
A
AB
WB
WV
R
DR
V
R
DR
DV )(
)(
)( (7)
where:
RWB(D) can be obtained from Equation 1 and Equation 2.
RAW(D) can be obtained from Equation 3 and Equation 4.
Operation of the digital potentiometer in the divider mode results
in a more accurate operation over temperature. Unlike the
rheostat mode, the output voltage is dependent mainly on the
ratio of the internal resistors, RAW and RWB, and not the absolute
values. Therefore, the temperature drift reduces to 5 ppm/°C.
TERMINAL VOLTAGE OPERATING RANGE
The AD5124/AD5144/AD5144A are designed with internal ESD
diodes for protection. These diodes also set the voltage boundary
of the terminal operating voltages. Positive signals present on
Terminal A, Terminal B, or Terminal W that exceed VDD are
clamped by the forward-biased diode. There is no polarity
constraint between VA, VW, and VB, but they cannot be higher
than VDD or lower than VSS.
V
DD
A
W
B
V
SS
10877-051
Figure 48. Maximum Terminal Voltages Set by VDD and VSS
POWER-UP SEQUENCE
Because there are diodes to limit the voltage compliance at
Terminal A, Terminal B, and Terminal W (see Figure 48), it is
important to power up VDD first before applying any voltage to
Terminal A, Terminal B, and Terminal W. Otherwise, the diode
is forward-biased such that VDD is powered unintentionally. The
ideal power-up sequence is VSS, VDD, VLOGIC, digital inputs, and
VA, VB, and VW. The order of powering VA, VB, VW, and digital
inputs is not important as long as they are powered after VSS,
VDD, and VLOGIC. Regardless of the power-up sequence and the
ramp rates of the power supplies, once VDD is powered, the
power-on preset activates, which restores EEPROM values to
the RDAC registers.
LAYOUT AND POWER SUPPLY BIASING
It is always a good practice to use a compact, minimum lead
length layout design. Ensure that the leads to the input are as
direct as possible with a minimum conductor length. Ground
paths should have low resistance and low inductance. It is also
good practice to bypass the power supplies with quality capacitors.
Apply low equivalent series resistance (ESR) 1 μF to 10 μF
tantalum or electrolytic capacitors at the supplies to minimize
any transient disturbance and to filter low frequency ripple.
Figure 49 illustrates the basic supply bypassing configuration
for the AD5124/AD5144/AD5144A.
V
DD
V
LOGIC
V
DD
V
LOGIC
+
V
SS
C1
0.1µF
C3
10µF +C6
10µF
C5
0.1µF
+C2
0.1µF
C4
10µF
V
SS
AD5124/
AD5144/
AD5144A
GND
10877-052
Figure 49. Power Supply Bypassing
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 33 of 36
OUTLINE DIMENSIONS
0.50
BSC
0.50
0.40
0.30
0.30
0.25
0.20
COMPLIANT
TO
JEDEC STANDARDS MO-220-WGG D-8.
06-11-2012-A
BOTTOM VIEWTOP VIEW
EXPOSED
PAD
PIN 1
INDICATOR
4.10
4.00 SQ
3.90
SEATING
PLANE
0.80
0.75
0.70
0.20 RE F
0.25 MIN
COPLANARITY
0.08
PIN 1
INDICATOR
2.20
2.10 SQ
2.00
1
24
7
12
13
1819
6
FOR PROPER CONNE CTI ON OF
THE E XPO S ED PAD, REFER TO
THE P IN CONFIG URATI ON AND
FUNCT IO N DES CRI P TI O NS
SECTION OF THIS DATA SHEET.
0.05 M A X
0.02 NOM
Figure 50. 24-Lead Lead Frame Chip Scale Package [LFCSP_WQ]
4 mm × 4 mm Body, Very Very Thin Quad
(CP-24-10)
Dimensions shown in millimeters
COMPLIANT TO JEDEC STANDARDS MO-153-AC
20
1
11
10
6.40 BSC
4.50
4.40
4.30
PIN 1
6.60
6.50
6.40
SEATING
PLANE
0.15
0.05
0.30
0.19
0.65
BSC 1.20 MAX 0.20
0.09 0.75
0.60
0.45
8°
0°
COPLANARIT
Y
0.10
Figure 51. 20-Lead Thin Shrink Small Outline Package [TSSOP]
(RU-20)
Dimensions shown in millimeters
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 34 of 36
ORDERING GUIDE
Model
1, 2
R
AB
(kΩ)
Resolution
Interface
Temperature Range
Package Description
Package Option
AD5124BCPZ10-RL7 10 128 SPI/I2C −40°C to +125°C 24-Lead LFCSP_WQ CP-24-10
AD5124BCPZ100-RL7 100 128 SPI/I2C −40°C to +125°C 24-Lead LFCSP_WQ CP-24-10
AD5124BRUZ10 10 128 SPI −40°C to +125°C 20-lead TSSOP RU-20
AD5124BRUZ100 100 128 SPI −40°C to +125°C 20-lead TSSOP RU-20
AD5124BRUZ10-RL7 10 128 SPI −40°C to +125°C 20-lead TSSOP RU-20
AD5124BRUZ100-RL7 100 128 SPI −40°C to +125°C 20-lead TSSOP RU-20
AD5144BCPZ10-RL7 10 256 SPI/I2C −40°C to +125°C 24-Lead LFCSP_WQ CP-24-10
AD5144BCPZ100-RL7 100 256 SPI/I2C −40°C to +125°C 24-Lead LFCSP_WQ CP-24-10
AD5144BRUZ10 10 256 SPI −40°C to +125°C 20-lead TSSOP RU-20
AD5144BRUZ100
100
256
SPI
−40°C to +125°C
20-lead TSSOP
RU-20
AD5144BRUZ10-RL7 10 256 SPI −40°C to +125°C 20-lead TSSOP RU-20
AD5144BRUZ100-RL7 100 256 SPI −40°C to +125°C 20-lead TSSOP RU-20
EVAL-AD5144DBZ Evaluation Board
AD5144ABRUZ10 10 256 I2C −40°C to +125°C 20-lead TSSOP RU-20
AD5144ABRUZ100 100 256 I2C −40°C to +125°C 20-lead TSSOP RU-20
AD5144ABRUZ10-RL7 10 256 I2C −40°C to +125°C 20-lead TSSOP RU-20
AD5144ABRUZ100-RL7 100 256 I2C −40°C to +125°C 20-lead TSSOP RU-20
1 Z = RoHS Compliant Part.
2 The evaluation board is shipped with the 10 kΩ RAB resistor option; however, the board is compatible with both of the available resistor value options.
Data Sheet AD5124/AD5144/AD5144A
Rev. A | Page 35 of 36
NOTES
AD5124/AD5144/AD5144A Data Sheet
Rev. A | Page 36 of 36
NOTES
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
©2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D10877-0-12/12(A)
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