Quad Channel, 128-/256-Position, I2C, Nonvolatile Digital Potentiometer AD5123/AD5143 Data Sheet FEATURES FUNCTIONAL BLOCK DIAGRAM VDD 10 k and 100 k 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 s Linear gain setting mode Single- and dual-supply operation Wide operating temperature: -40C to +125C 3 mm x 3 mm package 4 kV ESD protection AD5123/AD5143 POWER-ON RESET RDAC1 A1 INPUT REGISTER 1 W1 B1 RDAC2 INPUT REGISTER 2 SCL A2 W2 B2 SDA SERIAL INTERFACE RDAC3 7/8 INPUT REGISTER 3 ADDR W3 B3 RDAC4 APPLICATIONS INPUT REGISTER 4 Portable electronics level adjustment LCD panel brightness and contrast controls Programmable filters, delays, and time constants Programmable power supplies W4 B4 GND 10878-001 EEPROM MEMORY VSS Figure 1. GENERAL DESCRIPTION Table 1. Family Models The AD5123/AD5143 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. Model AD51231 AD5124 AD5124 AD5143 AD5144 AD5144 AD5144A AD5122 AD5122A AD5142 AD5142A AD5121 AD5141 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 the devices suitable for filter design. 1 The low wiper resistance of only 40 at the ends of the resistor array allows for pin-to-pin connection. Channel Quad Quad Quad Quad Quad Quad Quad Dual Dual Dual Dual Single Single Position 128 128 128 256 256 256 256 128 128 256 256 128 256 Interface I2C SPI/I2C SPI I2C SPI/I2C SPI I2C SPI I2C SPI I2C SPI/I2C SPI/I2C Package LFCSP LFCSP TSSOP LFCSP LFCSP TSSOP TSSOP LFCSP/TSSOP LFCSP/TSSOP LFCSP/TSSOP LFCSP/TSSOP LFCSP LFCSP Two potentiometers and two rheostats. The wiper values can be set through an I2C-compatible digital interface that is also used to read back the wiper register and EEPROM contents. The AD5123/AD5143 are available in a compact, 16-lead, 3 mm x 3 mm LFCSP. The parts are guaranteed to operate over the extended industrial temperature range of -40C to +125C. Rev. A Document Feedback Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 (c)2012-2013 Analog Devices, Inc. All rights reserved. Technical Support www.analog.com AD5123/AD5143 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation ...................................................................... 19 Applications ....................................................................................... 1 RDAC Register and EEPROM .................................................. 19 Functional Block Diagram .............................................................. 1 Input Shift Register .................................................................... 19 General Description ......................................................................... 1 I2C Serial Data Interface ............................................................ 19 Revision History ............................................................................... 2 I2C Address.................................................................................. 19 Specifications..................................................................................... 3 Advanced Control Modes ......................................................... 21 Electrical Characteristics--AD5123 .......................................... 3 EEPROM or RDAC Register Protection ................................. 22 Electrical Characteristics--AD5143 .......................................... 6 RDAC Architecture .................................................................... 25 Interface Timing Specifications .................................................. 9 Programming the Variable Resistor ......................................... 25 Shift Register and Timing Diagrams ....................................... 10 Programming the Potentiometer Divider ............................... 26 Absolute Maximum Ratings .......................................................... 11 Terminal Voltage Operating Range ......................................... 26 Thermal Resistance .................................................................... 11 Power-Up Sequence ................................................................... 26 ESD Caution ................................................................................ 11 Layout and Power Supply Biasing ............................................ 26 Pin Configuration and Function Descriptions ........................... 12 Outline Dimensions ....................................................................... 27 Typical Performance Characteristics ........................................... 13 Ordering Guide .......................................................................... 27 Test Circuits ..................................................................................... 18 REVISION HISTORY 3/13--Rev. 0 to Rev. A Changes to Features Section............................................................ 1 10/12--Revision 0: Initial Version Rev. A | Page 2 of 28 Data Sheet AD5123/AD5143 SPECIFICATIONS ELECTRICAL CHARACTERISTICS--AD5123 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; -40C < TA < +125C, unless otherwise noted. Table 2. Parameter DC CHARACTERISTICS--RHEOSTAT MODE (ALL RDACs) Resolution Resistor Integral Nonlinearity 2 Resistor Differential Nonlinearity2 Nominal Resistor Tolerance Resistance Temperature Coefficient3 Wiper Resistance3 Bottom Scale or Top Scale Nominal Resistance Match DC CHARACTERISTICS--POTENTIOMETER DIVIDER MODE (ALL RDACs) Integral Nonlinearity 4 Differential Nonlinearity4 Full-Scale Error Zero-Scale Error Voltage Divider Temperature Coefficient3 Symbol Test Conditions/Comments N R-INL Min Typ 1 Max 7 RAB = 10 k VDD 2.7 V VDD < 2.7 V RAB = 100 k VDD 2.7 V VDD < 2.7 V R-DNL RAB/RAB (RAB/RAB)/T x 106 RW Unit Bits -1 -2.5 0.1 1 +1 +2.5 LSB LSB -0.5 -1 -0.5 -8 0.1 0.25 0.1 1 35 +0.5 +1 +0.5 +8 LSB LSB LSB % ppm/C 55 130 125 400 -1 40 60 0.2 80 230 +1 % RAB = 10 k RAB = 100 k -0.5 -0.25 -0.25 0.1 0.1 0.1 +0.5 +0.25 +0.25 LSB LSB LSB RAB = 10 k RAB = 100 k -1.5 -0.5 -0.1 0.1 +0.5 LSB LSB Code = full scale Code = zero scale RAB = 10 k RAB = 100 k RBS or RTS RAB = 10 k RAB = 100 k Code = 0xFF RAB1/RAB2 INL DNL VWFSE VWZSE (VW/VW)/T x 106 RAB = 10 k RAB = 100 k Code = half scale Rev. A | Page 3 of 28 1 0.25 5 1.5 0.5 LSB LSB ppm/C AD5123/AD5143 Parameter RESISTOR TERMINALS Maximum Continuous Current Terminal Voltage Range 5 Capacitance A, Capacitance B3 Capacitance W3 Common-Mode Leakage Current3 DIGITAL INPUTS Input Logic3 High Low Input Hysteresis3 Input Current3 Input Capacitance3 DIGITAL OUTPUTS Output High Voltage3 Output Low Voltage3 Three-State Leakage Current Three-State Output Capacitance POWER SUPPLIES Single-Supply Power Range Dual-Supply Power Range Positive Supply Current Negative Supply Current EEPROM Store Current3, 6 EEPROM Read Current3, 7 Power Dissipation 8 Power Supply Rejection Ratio Data Sheet Symbol Test Conditions/Comments Min RAB = 10 k RAB = 100 k -6 -1.5 VSS Typ 1 Max Unit +6 +1.5 VDD mA mA V IA, IB, and IW CA, CB CW f = 1 MHz, measured to GND, code = half scale RAB = 10 k RAB = 100 k f = 1 MHz, measured to GND, code = half scale RAB = 10 k RAB = 100 k VA = V W = V B VINH VINL VHYST IIN CIN VOH VOL -500 25 12 pF pF 12 5 15 pF pF nA +500 0.7 x VDD 0.2 x VDD 0.1 x VDD 1 5 RPULL-UP = 2.2 k to VDD ISINK = 3 mA ISINK = 6 mA VDD -1 0.4 0.6 +1 V V V A pF 5.5 2.75 V V 5.5 A nA A mA A W dB 2 VSS = GND IDD ISS IDD_EEPROM_STORE IDD_EEPROM_READ PDISS PSRR VIH = VDD or VIL = GND VDD = 5.5 V VDD = 2.3 V VIH = VDD or VIL = GND VIH = VDD or VIL = GND VIH = VDD or VIL = GND VIH = VDD or VIL = GND VDD/VSS = VDD 10%, code = full scale Rev. A | Page 4 of 28 2.3 2.25 -5.5 0.7 400 -0.7 2 320 3.5 -66 V V V A pF -60 Data Sheet Parameter DYNAMIC CHARACTERISTICS 9 Bandwidth Total Harmonic Distortion Resistor Noise Density VW Settling Time AD5123/AD5143 Symbol Test Conditions/Comments BW -3 dB RAB = 10 k RAB = 100 k VDD/VSS = 2.5 V, VA = 1 V rms, VB = 0 V, f = 1 kHz RAB = 10 k RAB = 100 k Code = half scale, TA = 25C, f = 10 kHz RAB = 10 k RAB = 100 k VA = 5 V, VB = 0 V, from zero scale to full scale, 0.5 LSB error band RAB = 10 k RAB = 100 k RAB = 10 k RAB = 100 k THD eN_WB tS Crosstalk (CW1/CW2) CT Analog Crosstalk Endurance 10 CTA Min TA = 25C Typ 1 Unit 3 0.43 MHz MHz -80 -90 dB dB 7 20 nV/Hz nV/Hz 2 12 10 25 -90 1 s s nV-sec nV-sec dB Mcycles kcycles Years 100 Data Retention 11 Max 50 Typical values represent average readings at 25C, VDD = 5 V, and VSS = 0 V. Resistor integral nonlinearity (R-INL) error 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 x 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 s. 8 PDISS is calculated from (IDD x VDD). 9 All dynamic characteristics use VDD/VSS = 2.5 V. 10 Endurance is qualified to 100,000 cycles per JEDEC Standard 22, Method A117 and measured at -40C to +125C. 11 Retention lifetime equivalent at junction temperature (TJ) = 125C 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. 1 2 Rev. A | Page 5 of 28 AD5123/AD5143 Data Sheet ELECTRICAL CHARACTERISTICS--AD5143 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; -40C < TA < +125C, unless otherwise noted. Table 3. Parameter DC CHARACTERISTICS--RHEOSTAT MODE (ALL RDACs) Resolution Resistor Integral Nonlinearity 2 Resistor Differential Nonlinearity2 Nominal Resistor Tolerance Resistance Temperature Coefficient3 Wiper Resistance3 Bottom Scale or Top Scale Nominal Resistance Match DC CHARACTERISTICS--POTENTIOMETER DIVIDER MODE (ALL RDACs) Integral Nonlinearity 4 Differential Nonlinearity4 Full-Scale Error Zero-Scale Error Voltage Divider Temperature Coefficient3 Symbol Test Conditions/Comments N R-INL Min Typ 1 Max 8 RAB = 10 k VDD 2.7 V VDD < 2.7 V RAB = 100 k VDD 2.7 V VDD < 2.7 V R-DNL RAB/RAB (RAB/RAB)/T x 106 RW Unit Bits -2 -5 0.2 1.5 +2 +5 LSB LSB -1 -2 -0.5 -8 0.1 0.5 0.2 1 35 +1 +2 +0.5 +8 LSB LSB LSB % ppm/C 55 130 125 400 -1 40 60 0.2 80 230 +1 % RAB = 10 k RAB = 100 k -1 -0.5 -0.5 0.2 0.1 0.2 +1 +0.5 +0.5 LSB LSB LSB RAB = 10 k RAB = 100 k -2.5 -1 -0.1 0.2 +1 LSB LSB Code = full scale Code = zero scale RAB = 10 k RAB = 100 k RBS or RTS RAB = 10 k RAB = 100 k Code = 0xFF RAB1/RAB2 INL DNL VWFSE VWZSE (VW/VW)/T x 106 RAB = 10 k RAB = 100 k Code = half scale Rev. A | Page 6 of 28 1.2 0.5 5 3 1 LSB LSB ppm/C Data Sheet Parameter RESISTOR TERMINALS Maximum Continuous Current Terminal Voltage Range 5 Capacitance A, Capacitance B3 Capacitance W3 Common-Mode Leakage Current3 DIGITAL INPUTS Input Logic3 High Low Input Hysteresis3 Input Current3 Input Capacitance3 DIGITAL OUTPUTS Output High Voltage3 Output Low Voltage3 Three-State Leakage Current Three-State Output Capacitance POWER SUPPLIES Single-Supply Power Range Dual-Supply Power Range Positive Supply Current Negative Supply Current EEPROM Store Current3, 6 EEPROM Read Current3, 7 Power Dissipation 8 Power Supply Rejection Ratio AD5123/AD5143 Symbol Test Conditions/Comments Min RAB = 10 k RAB = 100 k -6 -1.5 VSS Typ 1 Max Unit +6 +1.5 VDD mA mA V IA, IB, and IW CA, CB CW f = 1 MHz, measured to GND, code = half scale RAB = 10 k RAB = 100 k f = 1 MHz, measured to GND, code = half scale RAB = 10 k RAB = 100 k VA = V W = V B VINH VINL VHYST IIN CIN VOH VOL -500 25 12 pF pF 12 5 15 pF pF nA +500 0.7 x VDD 0.2 x VDD 0.1 x VDD 1 5 RPULL-UP = 2.2 k to VDD ISINK = 3 mA ISINK = 6 mA VDD -1 0.4 0.6 +1 V V V A pF 5.5 2.75 V V 5.5 A nA A mA A W dB 2 VSS = GND IDD ISS IDD_EEPROM_STORE IDD_EEPROM_READ PDISS PSRR VIH = VDD or VIL = GND VDD = 5.5 V VDD = 2.3 V VIH = VDD or VIL = GND VIH = VDD or VIL = GND VIH = VDD or VIL = GND VIH = VDD or VIL = GND VDD/VSS = VDD 10%, code = full scale Rev. A | Page 7 of 28 2.3 2.25 -5.5 0.7 400 -0.7 2 320 3.5 -66 V V V A pF -60 AD5123/AD5143 Parameter DYNAMIC CHARACTERISTICS 9 Bandwidth Total Harmonic Distortion Resistor Noise Density VW Settling Time Data Sheet Symbol Test Conditions/Comments BW -3 dB RAB = 10 k RAB = 100 k VDD/VSS = 2.5 V, VA = 1 V rms, VB = 0 V, f = 1 kHz RAB = 10 k RAB = 100 k Code = half scale, TA = 25C, f = 10 kHz RAB = 10 k RAB = 100 k VA = 5 V, VB = 0 V, from zero scale to full scale, 0.5 LSB error band RAB = 10 k RAB = 100 k RAB = 10 k RAB = 100 k THD eN_WB tS Crosstalk (CW1/CW2) CT Analog Crosstalk Endurance 10 CTA Min TA = 25C Typ 1 Unit 3 0.43 MHz MHz -80 -90 dB dB 7 20 nV/Hz nV/Hz 2 12 10 25 -90 1 s s nV-sec nV-sec dB Mcycles kcycles Years 100 Data Retention 11 Max 50 Typical values represent average readings at 25C, VDD = 5 V, and VSS = 0 V. Resistor integral nonlinearity (R-INL) error 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 x 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 s. 8 PDISS is calculated from (IDD x VDD). 9 All dynamic characteristics use VDD/VSS = 2.5 V. 10 Endurance is qualified to 100,000 cycles per JEDEC Standard 22, Method A117 and measured at -40C to +125C. 11 Retention lifetime equivalent at junction temperature (TJ) = 125C 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. 1 2 Rev. A | Page 8 of 28 Data Sheet AD5123/AD5143 INTERFACE TIMING SPECIFICATIONS VDD = 2.3 V to 5.5 V; all specifications TMIN to TMAX, unless otherwise noted. Table 4. I2C Interface Parameter 1 fSCL 2 t1 t2 t3 t4 t5 t6 t7 t8 t9 t10 t11 t11A t12 tSP 3 tEEPROM_PROGRAM 4 tEEPROM_READBACK tPOWER_UP 5 tRESET Test Conditions/Comments Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Fast mode Standard mode Min Fast mode Standard mode Fast mode Fast mode 20 + 0.1 CL Typ 4.0 0.6 4.7 1.3 250 100 0 0 4.7 0.6 4 0.6 4.7 1.3 4 0.6 Max 100 400 3.45 0.9 1000 300 300 300 1000 300 1000 20 + 0.1 CL 20 + 0.1 CL 20 + 0.1 CL 20 + 0.1 CL 0 15 7 30 300 300 300 50 50 30 75 Unit kHz kHz s s s s ns ns s s s s s s s s s s ns ns ns ns ns ns ns ns ns ns ns ms s s s Description Serial clock frequency SCL high time, tHIGH SCL low time, tLOW Data setup time, tSU; DAT Data hold time, tHD; DAT Setup time for a repeated start condition, tSU; STA Hold time (repeated) for a start condition, tHD; STA Bus free time between a stop and a start condition, tBUF Setup time for a stop condition, tSU; STO Rise time of SDA signal, tRDA Fall time of SDA signal, tFDA Rise time of SCL signal, tRCL Rise time of SCL signal after a repeated start condition and after an acknowledge bit, tRCL1 (not shown in Figure 3) Fall time of SCL signal, tFCL Pulse width of suppressed spike (not shown in Figure 3) Memory program time (not shown in Figure 3) Memory readback time (not shown in Figure 3) Power-on EEPROM restore time (not shown in Figure 3) Reset EEPROM restore time (not shown in Figure 3) Maximum bus capacitance is limited to 400 pF. 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. 4 EEPROM program time depends on the temperature and EEPROM write cycles. Higher timing is expected at lower temperatures and higher write cycles. 5 Maximum time after VDD - VSS is equal to 2.3 V. 1 2 Rev. A | Page 9 of 28 AD5123/AD5143 Data Sheet SHIFT REGISTER AND TIMING DIAGRAMS C3 C2 C1 C0 A3 A2 A1 DB8 DB7 A0 D7 DB0 (LSB) D6 D5 D4 D3 D2 D1 D0 10878-002 DB15 (MSB) DATA BITS ADDRESS BITS CONTROL BITS Figure 2. Input Shift Register Contents t11 t12 t6 t8 t2 SCL t5 t1 t6 t4 t10 t3 t9 t7 P S S 2 Figure 3. I C Serial Interface Timing Diagram (Typical Write Sequence) Rev. A | Page 10 of 28 P 10878-003 SDA Data Sheet AD5123/AD5143 ABSOLUTE MAXIMUM RATINGS TA = 25C, unless otherwise noted. Table 5. Parameter VDD to GND VSS to GND VDD to VSS VA, VW, VB to GND Rating -0.3 V to +7.0 V +0.3 V to -7.0 V 7V VSS - 0.3 V, VDD + 0.3 V or +7.0 V (whichever is less) IA, IW, IB Pulsed 1 Frequency > 10 kHz RAW = 10 k RAW = 100 k Frequency 10 kHz RAW = 10 k RAW = 100 k Digital Inputs Operating Temperature Range, TA Maximum Junction Temperature, TJ Maximum Storage Temperature Range Reflow Soldering Peak Temperature Time at Peak Temperature Package Power Dissipation ESD 4 FICDM 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 JA is defined by the JEDEC JESD51 standard, and the value is dependent on the test board and test environment. Table 6. Thermal Resistance 6 mA/d 2 1.5 mA/d2 3 Package Type 16-Lead LFCSP 6 mA/d2 1.5 mA/d2 -0.3 V to VDD + 0.3 V or +7 V (whichever is less) -40C to +125C 150C 1 JA 89.51 JEDEC 2S2P test board, still air (0 m/sec airflow). ESD CAUTION -65C to +150C 260C 20 sec to 40 sec (TJ max - TA)/JA 4 kV 1.5 kV 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. 1 Rev. A | Page 11 of 28 JC 3 Unit C/W AD5123/AD5143 Data Sheet PIN 1 INDICATOR A1 1 B3 5 A2 7 TOP VIEW (Not to Scale) 12 VDD 11 B4 10 W4 9 B2 W2 8 W3 4 VSS 6 B1 3 AD5123/ AD5143 W1 2 NOTES 1. INTERNALLY CONNECT THE EXPOSED PAD TO VSS. 10878-004 14 SDA 13 SCL 16 GND 15 ADDR PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 4. Pin Configuration Table 7. Pin Function Descriptions Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Mnemonic A1 W1 B1 W3 B3 VSS A2 W2 B2 W4 B4 VDD SCL SDA ADDR GND EPAD Description Terminal A of RDAC1. VSS VA VDD. Wiper Terminal of RDAC1. VSS VW VDD. Terminal B of RDAC1. VSS VB VDD. Wiper Terminal of RDAC3. VSS VW VDD. Terminal B of RDAC3. VSS VB VDD. Negative Power Supply. Decouple this pin with 0.1 F ceramic capacitors and 10 F capacitors. Terminal A of RDAC2. VSS VA VDD. Wiper Terminal of RDAC2. VSS VW VDD. Terminal B of RDAC2. VSS VB VDD. Wiper Terminal of RDAC4. VSS VW VDD. Terminal B of RDAC4. VSS VB VDD. Positive Power Supply. Decouple this pin with 0.1 F ceramic capacitors and 10 F capacitors. Serial Clock Line. Data is clocked in at the logic low transition. Serial Data Input/Output. Programmable Address for Multiple Package Decoding. Ground Pin, Logic Ground Reference. Internally Connect the Exposed Paddle to VSS. Rev. A | Page 12 of 28 Data Sheet AD5123/AD5143 TYPICAL PERFORMANCE CHARACTERISTICS 0.5 0.2 10k, +125C 10k, +25C 10k, -40C 100k, +125C 100k, +25C 100k, -40C 0.4 0.3 0.1 0 R-DNL (LSB) R-INL (LSB) 0.2 0.1 0 -0.1 -0.1 -0.2 -0.3 -0.2 -0.4 -0.3 100 0 200 CODE (Decimal) -0.6 10878-005 -0.5 10k, +125C 10k, +25C 10k, -40C 100k, +125C 100k, +25C 100k, -40C 100 0 200 CODE (Decimal) Figure 5. R-INL vs. Code (AD5143) 10878-008 -0.5 -0.4 Figure 8. R-DNL vs. Code (AD5143) 0.20 0.10 0.15 0.05 0.10 0 R-DNL (LSB) R-INL (LSB) 0.05 0 -0.05 -0.05 -0.10 -0.15 -0.10 10k, +125C 10k, +25C 10k, -40C 100k, +125C 100k, +25C 100k, -40C -0.25 0 -0.25 50 100 -0.30 CODE (Decimal) 10k, +125C 10k, +25C 10k, -40C 0 100 Figure 9. R-DNL vs. Code (AD5123) 0.10 10k, -40C 10k, +25C 10k, +125C 100k, -40C 100k, +25C 100k, +125C 0.2 50 CODE (Decimal) Figure 6. R-INL vs. Code (AD5123) 0.3 100k, +125C 100k, +25C 100k, -40C 10878-009 -0.20 -0.20 10878-006 -0.15 0.05 0 DNL (LSB) 0 -0.05 -0.10 -0.15 -0.1 -0.20 -0.2 -0.3 0 100 CODE (Decimal) 200 -0.30 10k, -40C 10k, +25C 10k, +125C 0 100 CODE (Decimal) Figure 10. DNL vs. Code (AD5143) Figure 7. INL vs. Code (AD5143) Rev. A | Page 13 of 28 100k, -40C 100k, +25C 100k, +125C 200 10878-010 -0.25 10878-007 INL (LSB) 0.1 AD5123/AD5143 Data Sheet 0.15 0.06 10k, -40C 10k, +25C 10k, +125C 100k, -40C 100k, +25C 100k, +125C 0.10 100k, -40C 100k, +25C 100k, +125C 0.02 0 0.05 -0.02 DNL (LSB) INL (LSB) 10k, -40C 10k, +25C 10k, +125C 0.04 0 -0.04 -0.06 -0.05 -0.08 -0.10 -0.10 -0.14 10878-011 50 0 100 CODE (Decimal) 0 50 450 10k 100k 400 RHEOSTAT MODE TEMPERATURE COEFFICIENT (ppm/C) 350 300 250 200 150 100 50 350 300 250 200 150 100 50 0 -50 50 100 150 200 255 AD5143 25 50 75 CODE (Decimal) 100 127 AD5123 -50 10878-012 0 0 Figure 12. Potentiometer Mode Temperature Coefficient ((VW/VW)/T x 106) vs. Code 800 700 IDD, VDD = 2.3V IDD, VDD = 3.3V IDD, VDD = 5V 0 50 100 150 200 255 AD5142A 0 25 50 75 CODE (Decimal) 100 127 AD5122A Figure 15. Rheostat Mode Temperature Coefficient ((RWB/RWB)/T x 106) vs. Code 1200 VSS = GND VDD VDD VDD VDD 1000 = 2.3V = 3.3V = 5V = 5.5V IDD CURRENT (A) 500 400 300 800 600 400 200 200 100 0 -40 10 60 TEMPERATURE (C) 110 125 10878-013 CURRENT (nA) 600 Figure 13. Supply Current vs. Temperature 0 0 1 2 3 4 INPUT VOLTAGE (V) Figure 16. IDD Current vs. Digital Input Voltage Rev. A | Page 14 of 28 5 10878-015 0 10878-016 POTENTIOMETER MODE TEMPERATURE COEFFICIENT (ppm/C) Figure 14. DNL vs. Code (AD5123) 100k 10k 400 100 CODE (Decimal) Figure 11. INL vs. Code (AD5123) 450 10878-014 -0.12 -0.15 Data Sheet AD5123/AD5143 10 0 0x80 (0x40) 0 -10 0x40 (0x20) 0x20 (0x10) 0x20 (0x10) -20 0x10 (0x08) 0x8 (0x04) GAIN (dB) GAIN (dB) -20 0x10 (0x08) 0x8 (0x04) -30 0x80 (0x40) -10 0x40 (0x20) 0x4 (0x02) 0x2 (0x01) -40 0x1 (0x00) -30 0x4 (0x02) -40 -50 0x2 (0x01) 0x1 (0x00) 0x00 -60 0x00 -70 -50 -80 1k 10k 100k 1M 10M FREQUENCY (Hz) -90 10 10878-017 100 100 -50 0 1M 10M 10k 100k -10 -20 -60 -30 THD + N (dB) THD + N (dB) 100k Figure 20. 100 k Gain vs. Frequency and Code 10k 100k VDD/VSS = 2.5V VA = 1V rms VB = GND CODE = HALF SCALE NOISE FILTER = 22kHz 10k FREQUENCY (Hz) Figure 17. 10 k Gain vs. Frequency and Code -40 1k 10878-020 AD5143 (AD5123) AD5143 (AD5123) -60 10 -70 -80 -40 -50 -60 -70 VDD/VSS = 2.5V -100 20 200 2k 200k 20k FREQUENCY (Hz) 10878-018 -80 Figure 18. Total Harmonic Distortion Plus Noise (THD + N) vs. Frequency CODE = HALF SCALE NOISE FILTER = 22kHz -90 0.001 0.01 1 Figure 21. Total Harmonic Distortion Plus Noise (THD + N) vs. Amplitude 10 VDD/VSS = 2.5V RAB = 10k 0 0 -10 -20 PHASE (Degrees) -20 -40 -60 -30 -40 -50 -60 -70 QUARTER SCALE MIDSCALE FULL-SCALE 100 1k -80 10k 100k 1M 10M FREQUENCY (Hz) Figure 19. Normalized Phase Flatness vs. Frequency, RAB = 10 k -90 10 QUARTER SCALE MIDSCALE FULL-SCALE 100 VDD/VSS = 2.5V RAB = 100k 1k 10k 100k 1M FREQUENCY (Hz) Figure 22. Normalized Phase Flatness vs. Frequency, RAB = 100 k Rev. A | Page 15 of 28 10878-022 -80 10878-019 PHASE (Degrees) 0.1 VOLTAGE (V rms) 20 -100 10 fIN = 1kHz 10878-021 -90 AD5123/AD5143 Data Sheet 300 200 0.8 0.0015 0.6 0.0010 0.4 0.0005 0.2 100 0 0 0 2 1 4 3 -600 -500 -400 -300 -200 -100 10878-023 0 5 VOLTAGE (V) 0 10k + 0pF 10k + 75pF 10k + 150pF 10k + 250pF 100k + 0pF 100k + 75pF 100k + 150pF 100k + 250pF 200 300 400 500 600 VDD = 5V 10% AC VSS = GND, VA = 4V, VB = GND CODE = MIDSCALE -20 -30 6 5 4 -40 -50 -60 3 -70 2 0 20 40 0 10 20 80 100 120 AD5143 40 30 CODE (Decimal) 50 60 60 AD5123 -90 10 10878-024 0 100k 1M 10M 0.020 0.015 RELATIVE VOLTAGE (V) 0.6 0.5 0.4 0.3 0.2 0.1 0.010 0.005 0 -0.005 -0.010 5 10 TIME (s) 15 10878-025 0 Figure 25. Maximum Transition Glitch -0.020 0 500 1000 1500 TIME (ns) Figure 28. Digital Feedthrough Rev. A | Page 16 of 28 2000 10878-028 -0.015 0 -0.1 10k Figure 27. Power Supply Rejection Ratio (PSRR) vs. Frequency 0x80 TO 0x7F 100k 0x80 TO 0x7F 10k 0.7 1k FREQUENCY (Hz) Figure 24. Maximum Bandwidth vs. Code and Net Capacitance 0.8 100 10878-027 -80 1 RELATIVE VOLTAGE (V) 10k, RDAC1 100k, RDAC1 -10 PSRR (dB) BANDWIDTH (MHz) 7 100 Figure 26. Resistor Lifetime Drift 10 8 0 RESISTOR DRIFT (ppm) Figure 23. Incremental Wiper On Resistance vs. Positive Power Supply (VDD) 9 CUMULATIVE PROBABILITY 400 1.0 0.0020 PROBABILITY DENSITY WIPER ON RESISTANCE () 500 1.2 0.0025 100k, V DD = 2.3V 100k, V DD = 2.7V 100k, V DD = 3V 100k, V DD = 3.6V 100k, V DD = 5V 100k, V DD = 5.5V 10k, VDD = 2.3V 10k, VDD = 2.7V 10k, VDD = 3V 10k, VDD = 3.6V 10k, VDD = 5V 10k, VDD = 5.5V 10878-026 600 Data Sheet 0 AD5123/AD5143 7 10k 100k SHUTDOWN MODE ENABLED 6 THEORETICAL IMAX (mA) -20 -60 -80 5 4 3 2 10k -100 1 100k 100 1k 10k 100k 1M FREQUENCY (Hz) 10M 0 0 0 50 25 100 150 50 75 CODE (Decimal) 200 100 250 AD5143 125 AD5123 Figure 30. Theoretical Maximum Current vs. Code Figure 29. Shutdown Isolation vs. Frequency Rev. A | Page 17 of 28 10878-030 -120 10 10878-029 GAIN (dB) -40 AD5123/AD5143 Data Sheet TEST CIRCUITS Figure 31 to Figure 35 define the test conditions used in the Specifications section. NC VA IW V+ = VDD 10% VDD B V+ VMS ~ Figure 31. Resistor Integral Nonlinearity Error (Rheostat Operation; R-INL, R-DNL) PSRR (dB) = 20 LOG W B 10878-031 NC = NO CONNECT A VMS PSS (%/%) = RSW = VDD% 0.1V ISW CODE = 0x00 W V+ B VMS B A = NC Figure 32. Potentiometer Divider Nonlinearity Error (INL, DNL) W VW B RW = VMS1/IW NC = NO CONNECT 10878-033 VMS1 - VSS TO VDD Figure 35. Incremental On Resistance IW = VDD/RNOMINAL DUT A 0.1V ISW 10878-035 W + V+ = VDD 1LSB = V+/2N 10878-032 DUT A Figure 33. Wiper Resistance Rev. A | Page 18 of 28 VMS VDD ) VMS% Figure 34. Power Supply Sensitivity and Power Supply Rejection Ratio (PSS, PSRR) DUT ( 10878-034 DUT A W Data Sheet AD5123/AD5143 THEORY OF OPERATION The AD5123/AD5143 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 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 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. I2C SERIAL DATA INTERFACE The AD5123/AD5143 has 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 3 for a timing diagram of a typical write sequence. The AD5123/AD5143 supports 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. 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 (AD5143, 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 9). 2. The contents of the RDAC register can be stored to the EEPROM using Command 9 (see Table 9). 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 9). 3. Alternatively, the EEPROM can be written to independently using Command 11 (see Table 15). INPUT SHIFT REGISTER For the AD5123/AD5143, the input shift register is 16 bits wide, as shown in Figure 2. The 16-bit word consists of four control bits, followed by four address bits and by eight data bits. If the AD5143 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 9 and Table 15. 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. 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. 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 facility to make hardwired changes to ADDR allows the user to incorporate up to three of these devices on one bus as outlined in Table 8. Table 8. I2C Address Selection ADDR Pin VDD No connect1 GND 1 7-Bit I2C Device Address 0101000 0101010 0101011 Not available in bipolar mode ( VSS < 0 V). Rev. A | Page 19 of 28 AD5123/AD5143 Data Sheet Table 9. Reduced Commands Operation Truth Table Command Number 0 1 Control Bits[DB15:DB12] C3 C2 C1 C0 0 0 0 0 0 0 0 1 Address Bits[DB11:DB8]1 A3 A2 A1 A0 X X X X 0 0 A1 A0 2 0 0 1 0 0 0 A1 3 0 0 1 1 0 0 9 10 14 15 0 0 1 1 1 1 0 1 1 1 1 0 1 1 1 0 0 0 X A3 0 0 X 0 1 D7 X D7 Data Bits[DB7:DB0]1 D6 D5 D4 D3 D2 D1 X X X X X X D6 D5 D4 D3 D2 D1 D0 X D0 A0 D7 D6 D5 D4 D3 D2 D1 D0 A1 A0 X X X X X X D1 D0 A1 A1 X A1 A0 A0 X A0 X X X X X X X X X X X X X X X X X X X X X X X X X X X X 1 0 X D0 Operation NOP: do nothing Write contents of serial register data to RDAC Write contents of serial register data to input register Read back contents D1 D0 Data 0 1 EEPROM 1 1 RDAC Copy RDAC register to EEPROM Copy EEPROM into RDAC Software reset Software shutdown D0 Condition 0 Normal mode 1 Shutdown mode X = don't care. Table 10. Reduced Address Bits Table A3 1 0 0 0 0 1 A2 X1 0 0 0 0 A1 X1 0 0 1 1 A0 X1 0 1 0 1 Channel All channels RDAC1 RDAC2 RDAC3 RDAC4 X = don't care. Rev. A | Page 20 of 28 Stored Channel Memory Not applicable RDAC1 RDAC2 RDAC3 RDAC4 Data Sheet AD5123/AD5143 ADVANCED CONTROL MODES Low Wiper Resistance Feature The AD5123/AD5143 digital potentiometers include a set of user programming features to address the wide number of applications for these universal adjustment devices (see Table 15 and Table 17). The AD5123/AD5143 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. 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 The contents of the RDAC registers are unchanged by entering in these positions. There are three ways to exit from top scale and bottom scale: by using Command 12 or Command 13 (see Table 15); by loading new data in an RDAC register, which includes increment/decrement operations; or by entering shutdown mode, Command 15 (see Table 15). Input Register The AD5123/AD5143 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 using Command 3 (see Table 15). 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 synchronously by Command 8 (see Table 15). If new data is loaded in an RDAC register, this RDAC register automatically overwrites the associated input register. Linear Gain Setting Mode The patented architecture of the AD5123/AD5143 allows the independent control of each string resistor, RAW, and RWB. To enable linear gain setting mode, use Command 16 (see Table 15) to set Bit D2 of the control register (see Table 17). This mode of operation can control the potentiometer as two independent rheostats connected at a single point, W terminal, as opposed to potentiometer mode where each resistor is complementary, RAW = RAB - RWB. This mode enables a second input and an RDAC register per channel, as shown in Table 16; however, the actual RDAC contents remain unchanged. The same operations are valid for potentiometer and linear setting gain modes. The parts restore in potentiometer mode after a reset or power-up. Table 11 and Table 12 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 11. Top Scale Truth Table Linear Gain Setting Mode RAW RWB RAB RAB RAW RTS Potentiometer Mode RWB RAB Table 12. Bottom Scale Truth Table Linear Gain Setting Mode RAW RWB RTS RBS RAW RAB Potentiometer Mode RWB RBS Linear Increment and Decrement Instructions The increment and decrement commands (Command 4 and Command 5 in Table 15) 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 resistance RDAC position. This command can be executed in a single channel or multiple channels. Rev. A | Page 21 of 28 AD5123/AD5143 Data Sheet 6 dB Increment and Decrement Instructions Reset 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 15). For example, starting with the zero-scale position and executing Command 6 ten times moves the wiper in 6 dB steps to the fullscale 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 13). The AD5123/AD5143 can be reset through software by executing Command 14 (see Table 15). The reset command loads the RDAC registers with the contents of the EEPROM and takes approximately 30 s. The EEPROM is preloaded to midscale at the factory, and initial power-up is, accordingly, at midscale. 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 AD5123/AD5143 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 13. Detailed Left Shift and Right Shift Functions for the 6 dB Step Increment and Decrement Left Shift (+6 dB/Step) 0000 0000 0000 0001 0000 0010 0000 0100 0000 1000 0001 0000 0010 0000 0100 0000 1000 0000 1111 1111 Right Shift (-6 dB/Step) 1111 1111 0111 1111 0011 1111 0001 1111 0000 1111 0000 0111 0000 0011 0000 0001 0000 0000 0000 0000 Shutdown Mode The AD5123/AD5143 can be placed in shutdown mode by executing the software shutdown command, Command 15 (see Table 15), 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 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 14 shows the 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 15 are supported while in shutdown mode. Execute Command 15 (see Table 15) and set the LSB (D0) to 0 to exit shutdown mode. Table 14. Truth Table for Shutdown Mode Linear Gain Setting Mode RAW RWB High impedance High impedance Potentiometer Mode RAW RWB 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 17), which protects the RDAC and EEPROM registers independently. When RDAC is protected, the only operation allowed is to copy the EEPROM into the RDAC register. Burst Mode By enabling the burst mode, multiple data bytes can be sent to the part consecutively. After the command byte, the part interprets the 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 17). Rev. A | Page 22 of 28 Data Sheet AD5123/AD5143 Table 15. Advance Commands Operation Truth Table Command Number 0 1 Control Bits[DB15:DB12] C3 C2 C1 C0 0 0 0 0 0 0 0 1 Address Bits[DB11:DB8]1 A3 A2 A1 A0 X X X X A3 A2 A1 A0 D7 X D7 2 0 0 1 0 A3 A2 A1 A0 3 0 0 1 1 X A2 A1 4 5 6 7 8 0 0 0 0 0 1 1 1 1 1 0 0 0 0 1 0 0 1 1 0 A3 A3 A3 A3 A3 A2 A2 A2 A2 A2 9 0 1 1 1 0 10 11 0 1 1 0 1 0 1 0 12 1 0 0 13 1 0 14 15 1 1 16 1 1 D6 X D6 Data Bits[DB7:DB0] 1 D5 D4 D3 D2 D1 X X X X X D5 D4 D3 D2 D1 D0 X D0 D7 D6 D5 D4 D3 D2 D1 D0 A0 X X X X X X D1 D0 A1 A1 A1 A1 A1 A0 A0 A0 A0 A0 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X 1 0 1 0 X 0 A1 A0 X X X X X X X 1 0 0 0 0 A1 A1 A0 A0 X D7 X D6 X D5 X D4 X D3 X D2 X D1 0 D0 1 A3 A2 A1 A0 1 X X X X X X D0 0 1 A3 A2 A1 A0 0 X X X X X X D0 0 1 1 0 1 0 X A3 X A2 X A1 X A0 X X X X X X X X X X X X X X X D0 1 0 1 X X X X X X X X D3 D2 D1 D0 Operation NOP: do nothing Write contents of serial register data to RDAC Write contents of serial register data to input register Read back contents D1 D0 Data 0 0 Input register 0 1 EEPROM 1 0 Control register 1 1 RDAC Linear RDAC increment Linear RDAC decrement +6 dB RDAC increment -6 dB RDAC decrement Copy input register to RDAC (software LRDAC) Copy RDAC register to EEPROM Copy EEPROM into RDAC Write contents of serial register data to EEPROM Top scale D0 = 0; normal mode D0 = 1; shutdown mode Bottom scale D0 = 1; enter D0 = 0; exit Software reset Software shutdown D0 = 0; normal mode D0 = 1; device placed in shutdown mode Copy serial register data to control register X = don't care. Table 16. Address Bits A3 1 0 0 0 0 0 0 0 0 1 A2 X1 0 1 0 1 0 1 0 1 A1 X1 0 0 0 0 1 1 1 1 A0 X1 0 0 1 1 0 0 1 1 Potentiometer Mode Input Register RDAC Register All channels All channels RDAC1 RDAC1 Not applicable Not applicable RDAC2 RDAC2 Not applicable Not applicable RDAC3 RDAC3 Not applicable Not applicable RDAC4 RDAC4 Not applicable Not applicable Linear Gain Setting Mode Input Register RDAC Register All channels All channels RWB1 RWB1 RAW1 RAW1 RWB2 RWB2 RAW2 RAW2 RWB3 RWB3 RAW3 RAW3 RWB4 RWB4 RAW4 RAW4 X = don't care. Rev. A | Page 23 of 28 Stored RDAC Memory Not applicable RDAC1 Not applicable RDAC2 Not applicable RDAC3 Not applicable RDAC4 Not applicable AD5123/AD5143 Data Sheet Table 17. Control Register Bit Descriptions Bit Name D0 D1 D2 D3 Description RDAC register write protect 0 = wiper position frozen to value in EEPROM memory 1 = allows update of wiper position through digital interface (default) EEPROM program enable 0 = EEPROM program disabled 1 = enables device for EEPROM program (default) Linear setting mode/potentiometer mode 0 = potentiometer mode (default) 1 = linear gain setting mode Burst mode 0 = disabled (default) 1 = enabled (no disable after stop or repeat start condition) Rev. A | Page 24 of 28 Data Sheet AD5123/AD5143 RDAC ARCHITECTURE To achieve optimum performance, Analog Devices, Inc., has patented the RDAC segmentation architecture for all the digital potentiometers. In particular, the AD5123/AD5143 employ a three-stage segmentation approach, as shown in Figure 36. The AD5123/AD5143 wiper switch is designed with the transmission gate CMOS topology and with the gate voltage derived from VDD and VSS. A 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 AD5123: RWB (D ) STS D R AB RW 128 From 0x00 to 0x7F (1) D R AB RW 256 From 0x00 to 0xFF (2) AD5143: RH RWB (D ) RM RH 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. RM RL W 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. RWA starts at the maximum resistance value and decreases as the data loaded into the latch increases. The general equations for this operation are RL 7-BIT/8-BIT ADDRESS DECODER RM RH RM RH SBS AD5123: 10878-036 B Figure 36. AD5123/AD5143 Simplified RDAC Circuit RAW (D ) RAW (D ) PROGRAMMING THE VARIABLE RESISTOR Rheostat Operation--8% Resistor Tolerance The AD5123/AD5143 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 37. A W B A W B B Figure 37. Rheostat Mode Configuration 256 D RAB RW 256 From 0x00 to 0xFF (4) (3) 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. 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 AD5123: R AW (D ) D R AB RW 128 From 0x00 to 0x7F (5) D R AB RW 256 From 0x00 to 0xFF (6) AD5143: W 10878-037 A From 0x00 to 0x7F AD5143: Top Scale/Bottom Scale Architecture In addition, the AD5123/AD5143 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 to 60 (RAB = 100 k). At top scale, the resistance between Terminal A and Terminal W is decreased by 1 LSB, and the total resistance is reduced to 60 (RAB = 100 k). 128 D RAB RW 128 R AW (D ) 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. Rev. A | Page 25 of 28 AD5123/AD5143 Data Sheet VDD In the bottom scale condition or top scale condition, a finite total wiper resistance of 40 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 5. Otherwise, degradation or possible destruction of the internal switch contact can occur. A W VSS PROGRAMMING THE POTENTIOMETER DIVIDER 10878-039 B Figure 39. Maximum Terminal Voltages Set by VDD and VSS Voltage Output Operation POWER-UP SEQUENCE 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 38. Because there are diodes to limit the voltage compliance at Terminal A, Terminal B, and Terminal W (see Figure 39), 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, 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 and VDD. 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. A VB VOUT B Figure 38. 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 VW (D) R (D) RWB (D) VA AW VB RAB RAB LAYOUT AND POWER SUPPLY BIASING (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. 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 F to 10 F tantalum or electrolytic capacitors at the supplies to minimize any transient disturbance and to filter low frequency ripple. Figure 40 illustrates the basic supply bypassing configuration for the AD5123/AD5143. VDD TERMINAL VOLTAGE OPERATING RANGE The AD5123/AD5143 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. Rev. A | Page 26 of 28 VSS + C3 10F C1 0.1F + C4 10F C2 0.1F VDD AD5123/ AD5143 VSS GND 10878-040 W 10878-038 VA Figure 40. Power Supply Bypassing Data Sheet AD5123/AD5143 OUTLINE DIMENSIONS PIN 1 INDICATOR 0.30 0.23 0.18 0.50 BSC PIN 1 INDICATOR 16 13 1 12 EXPOSED PAD 1.75 1.60 SQ 1.45 9 TOP VIEW 0.80 0.75 0.70 0.50 0.40 0.30 4 8 0.25 MIN BOTTOM VIEW 0.05 MAX 0.02 NOM COPLANARITY 0.08 0.20 REF SEATING PLANE 5 FOR PROPER CONNECTION OF THE EXPOSED PAD, REFER TO THE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS SECTION OF THIS DATA SHEET. COMPLIANT TO JEDEC STANDARDS MO-220-WEED-6. 08-16-2010-E 3.10 3.00 SQ 2.90 Figure 41. 16-Lead Lead Frame Chip Scale Package [LFCSP_WQ] 3 mm x 3 mm Body, Very Very Thin Quad (CP-16-22) Dimensions shown in millimeters ORDERING GUIDE Model1, 2 AD5123BCPZ10-RL7 AD5123BCPZ100-RL7 AD5143BCPZ10-RL7 AD5143BCPZ100-RL7 EVAL-AD5143DBZ 1 2 RAB (k) 10 100 10 100 Resolution 128 128 256 256 Interface I2C I2C I2C I2C Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package Description 16-Lead LFCSP_WQ 16-Lead LFCSP_WQ 16-Lead LFCSP_WQ 16-Lead LFCSP_WQ Evaluation Board Package Option CP-16-22 CP-16-22 CP-16-22 CP-16-22 Z = RoHS Compliant Part. The evaluation board is shipped with the 10 k RAB resistor option; however, the board is compatible with all of the available resistor value options. Rev. A | Page 27 of 28 Branding DGZ DH0 DH1 DH2 AD5123/AD5143 Data Sheet NOTES I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors). (c)2012-2013 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D10878-0-3/13(A) Rev. A | Page 28 of 28 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: Analog Devices Inc.: AD5123BCPZ100-RL7 AD5143BCPZ100-RL7 EVAL-AD5143DBZ AD5123BCPZ10-RL7 AD5143BCPZ10-RL7