Data Sheet AS1500/1/2/3 Digital Potentiometer AS1500/AS1501/AS1502/AS1503 Key Features - - DATASHEET PRELIMINARY FACT SHEET programming rates up to 10MHz. The AS1500 is available in four different resistor values. The AS1500 incorporates a 256-Position Available in four Resistance values - AS1500 resistance 10kOhms - AS1501 resistance 20kOhms - AS1502 resistance 50kOhms - AS1503 resistance 100kOhms Power Shutdown --Less than 1 A 3-Wire SPI-Compatible Serial Data Input 10 MHz Update Data Loading Rate 2.7 V to 5.5 V Single-Supply Operation Temperature Range -40C to +125C Package SO-8 Compatible to AD8400 10k, the AS1501 a 20k, the AS1502 a 50k and the AS1503 a 100k fixed resistor. The wiper contact taps the fixed resistor at points determined by the 8-bit digital code word. The resistance between the wiper and the endpoint of the resistor is linear. The switching action is performed in a way that no glitches occur. Furthermore the AS150x product family includes a shutdown mode, where it consumes less than 1A. The AS150x is available in an 8-pin SOIC package. All parts are guaranteed to operate over the extended industrial temperature range of -40C to +125C. Applications General Description - The AS1500 is a digital potentiometer with 256 programmable steps. The values of the resistor can be controlled via 3 wire serial interface capable to handle - Line Impedance Matching Volume Control, Panning Mechanical Potentiometer Replacement Power Supply Adjustment Programmable Filters, Delays, Time Constants VDD B 1 GND 2 CSN 3 SDI 4 8 AS150x Top View A SDI 7 W CK 6 VDD CSN 5 CK A 10 Bit Serial Latch 8 8-Bit Latch 8 W B AS1500 GND Figure 1 Pinout andfunctional Block Diagram of Digital Potentiometer AS150x family Revision 1.0, Oct 2004 Page 1 of 8 Data Sheet AS1500/1/2/3 ABSOLUTE MAXIMUM RATINGS (TA = 25C, unless otherwise noted.) Parameter VDD to GND VA, VB, VW to GND AX - BX, AX - WX, BX - WX Digital Input and Output Voltage to GND Operating Temperature Range Maximum Junction Temperature (TJ max) Storage Temperature Package body temperature 1 Limits -0.3V, +7V 0V, VDD 20mA 0V, +7V -40C to +125C 150C -65C to +150C 260C Package Power Dissipation (TJ max - TA) / JA ESD 1kV 2 Table 1: Absolute Maximum Ratings Pin 1 2 3 4 5 6 7 8 Table 1 2 Name B GND Description Terminal B RDAC Ground Chip Select Input, Active Low. When CS returns high, CSN data in the serial input register is loaded into the DAC register. SDI Serial Data Input CK Serial Clock Input, Positive Edge Triggered. Positive power supply, specified for operation at both 3V VDD and 5V. W Wiper RDAC A Terminal A RDAC 2: Pin Function Description The reflow peak soldering temperature (body temperature) is specified according IPC/JEDEC J-STD-020C "Moisture/Reflow Sensitivity Classification for non hermetic Solid State Surface Mount Devices". HBM MIL-Std883E 3015.7methods. Revision 1.0, Oct 2004 Page 2 of 8 Data Sheet AS1500/1/2/3 AS1500 / AS1501 - SPECIFICATIONS VDD = 3V10% or 5V10%, V A = VDD, V B = 0V, -40C T A +125C unless otherwise noted. ELECTRICAL CHARACTERISTICS - 10k and 20k VERSIONS Parameter Symbol Conditions DC CHARACTERISTICS RHEOSTAT MODE T A = 25C, VDD = 5V, AS1500, Version: 10k Nominal Resistance 4 R AB T A = 25C, VDD = 5V, AS1501, Version: 20k Resistance Tempco 5 R AB /T V AB = VDD, Wiper = No Connect Wiper Resistance RW VDD = 5V Resistor Differential NL 6 R-DNL R WB , VDD = 5V, V A = No Connect Resistor Integral NL R-INL R WB , VDD = 5V, V A = No Connect DC CHARACTERISTICS POTENTIOMETER DIVIDER Resolution N VDD = 5.5V T A = 25C Integral Nonlinearity INL VDD = 2.7V T A = 25C VDD = 5.5V T A = 25C Differential Nonlinearity DNL VDD = 2.7V T A = 25C Voltage Divider Tempco V W /T Code = 80 H Full-Scale Error V WFSE Code = FF H , VDD = 5.5V Zero-Scale Error V WZSE Code = 00 H , VDD = 5.5V RESISTOR TERMINALS Voltage Range 7 V A, B, W Capacitance 8 Ax, Bx C A, B f =1MHz, Measured to GND, Code = 80 H Capacitance Wx CW f =1MHz, Measured to GND, Code = 80 H DIGITAL INPUTS AND OUTPUTS Input Logic High V IH VDD = 5V Input Logic Low V IL VDD = 5V Input Logic High V IH VDD = 3V Input Logic Low V IL VDD = 3V Input Current I IH , I IL V IN = 5V or 0V, VDD = 5V Input Capacitance C IL POWER SUPPLIES Power Supply Range VDD Supply Current (CMOS) IDD V IH = VDD or V IL = 0V, VDD = 5.5V Supply Current (TTL) 9 IDD V IH = 2.4V or 0.8V, VDD = 5.5V Power Dissipation P V DISS IH = VDD or V IL = 0V, VDD = 5.5V (CMOS) 10 AS1500, Version: 10k Power Supply Suppression VDD = 5V + 0.5V P PSSR sine wave @ 1kHz Ratio AS1501, Version: 20k DYNAMIC CHARACTERISTICS 11 BW_10k R WB = 10k, VDD = 5V Bandwidth -3dB Bandwidth -3dB BW_20k R WB = 20k, VDD = 5V Total Harmonic Distortion THD W V A = 1V RMS + 2V DC , V B = 2V DC , f = 1kHz R WB = 5k, V A = VDD, V B = 0V, 1% Error t S _10k Band V W Settling Time R WB = 10k, V A = VDD, V B = 0V, 1% Error t S _20k Band e NWB _10k R WB = 5k, f =1kHz Resistor Noise Voltage e NWB _20k R WB = 10k, f =1kHz Min Typ 3 Max Unit 8 16 10 20 500 100 1/4 1/2 12 24 k k ppm/C LSB LSB 20 -1 -2 -2 -2 -1 -1 -4 0 8 1/2 1/2 1/4 1/4 15 -2.8 1.3 0 200 +1 +2 +2 +2 +1 +1 0 2 VDD 75 120 2.4 0.8 2.1 0.6 1 5 2.7 0.1 0.9 -54 -52 Bits LSB LSB LSB LSB ppm/C LSB LSB V pF pF V V V V A pF 5.5 1 4 V A mA 27.5 W -25 -25 dB dB 1000 500 0.003 kHz kHz % 2 s 4 s 9 13 nV/ Hz nV/ Hz Table 3: Electrical Characteristics - 10k and 20k Versions 3 Typicals represent average readings at 25C and VDD = 5V. Wiper is not connected. I AB = 350A for the 10k version and 175A for the 20k version. 5 All Tempcos are guaranteed by design and not subject to production test. 6 Terminal A is not connected. I W = 350A for the 10k version and 175A for the 20k version. 7 Resistor terminals A, B, W have no limitations on polarity with respect to each other. 8 All capacitances are guaranteed by design and not subject to production test. Resistor-terminal capacitance tests are measured with 2.5V bias on the measured terminal. The remaining resistor terminals are left open circuit. 9 Worst-case supply current consumed when input logic level at 2.4V, standard characteristic of CMOS logic. 10 P DI SS is calculated from (IDDxVDD). CMOS logic level inputs result in minimum power dissipation. 11 All dynamic characteristics are guaranteed by design and not subject to production test. All dynamic characteristics use VDD=5V. 4 Revision 1.0, Oct 2004 Page 3 of 8 Data Sheet AS1500/1/2/3 AS1502 / AS1503 - SPECIFICATIONS VDD = 3V10% or 5V10%, V A = VDD, V B = 0V, -40C T A +125C unless otherwise noted. ELECTRICAL CHARACTERISTICS - 50k and 100k VERSIONS Parameter Symbol Conditions DC CHARACTERISTICS RHEOSTAT MODE T A = 25C, VDD = 5V, AS1502, Version: 50k Nominal Resistance 13 R AB T A = 25C, VDD = 5V, AS1503, Version: 100k Resistance Tempco 14 R AB /T V AB = VDD, Wiper = No Connect Wiper Resistance RW VDD = 5V Resistor Differential NL 15 R-DNL R WB , VDD = 5V, V A = No Connect Resistor Integral NL R-INL R WB , VDD = 5V, V A = No Connect DC CHARACTERISTICS POTENTIOMETER DIVIDER Resolution N VDD = 5.5V T A = 25C Integral Nonlinearity INL VDD = 2.7V T A = 25C VDD = 5.5V T A = 25C Differential Nonlinearity DNL VDD = 2.7V T A = 25C Voltage Divider Tempco V W /T Code = 80 H Full-Scale Error V WFSE Code = FF H , VDD = 5.5V Zero-Scale Error V WZSE Code = 00 H , VDD = 5.5V RESISTOR TERMINALS Voltage Range 16 V A, B, W Capacitance 17 Ax, Bx C A, B f = 1MHz, Measured to GND, Code = 80 H Capacitance Wx CW f = 1MHz, Measured to GND, Code = 80 H DIGITAL INPUTS AND OUTPUTS Input Logic High V IH VDD = 5V Input Logic Low V IL VDD = 5V Input Logic High V IH VDD = 3V Input Logic Low V IL VDD = 3V Input Current I IH , I IL V IN = 5V or 0V, VDD = 5V Input Capacitance C IL POWER SUPPLIES Power Supply Range VDD Supply Current (CMOS) IDD V IH = VDD or V IL = 0V, VDD = 5.5V Supply Current (TTL) 18 IDD V IH = 2.4V or 0.8V, VDD = 5.5V Power Dissipation P DISS V IH = VDD or V IL = 0V, VDD = 5.5V (CMOS) 19 AS1502, Version: 50k Power Supply Suppression VDD = 5V + 0.5V P PSSR AS1503, Version: sine wave @ 1kHz Ratio 100k DYNAMIC CHARACTERISTICS 20 BW_50k R WB = 50k, VDD = 5V Bandwidth -3dB Bandwidth -3dB BW_100k R WB = 100k, VDD = 5V Total Harmonic Distortion THD W V A = 1V RMS + 2V DC , V B = 2V DC , f = 1kHz R WB = 50k, V A = VDD, V B = 0V, 1% Error t S _50k Band V W Settling Time R WB = 100k, V A = VDD, V B = 0V, 1% Error t S _100k Band e NWB _50k R WB = 50k, f = 1kHz Resistor Noise Voltage e NWB _100 R WB = 100k, f = 1kHz k Min Typ 12 Max Unit 40 80 50 100 500 100 1/4 1/2 60 120 k k ppm/C LSB LSB 20 -1 -2 -4 -4 -1 -1 -1 0 8 1 1 1/4 1/4 15 -0.25 0.1 0 200 +1 +2 +4 +4 +1 +1 0 1 VDD 15 80 2.4 0.8 2.1 0.6 1 5 2.7 Bits LSB LSB LSB LSB ppm/C LSB LSB V pF pF V V V V A pF 5.5 1 4 V A mA 27.5 W -43 tbd. dB -48 tbd. dB 0.1 0.9 220 110 0.003 kHz kHz % 9 s 18 s 20 nV/ Hz 29 nV/ Hz Table 4: Electrical Characteristics - 50k and 100k Versions Typicals represent average readings at 25C and VDD = 5V. Wiper is not connected. I AB = 70A for the 50k version and 35A for the 100k version. 14 All Tempcos are guaranteed by design and not subject to production test. 15 Terminal A is not connected. I W = 70A for the 50k version and 35A for the 100k version. 16 Resistor terminals A, B, W have no limitations on polarity with respect to each other. 17 All capacitances are guaranteed by design and not subject to production test. Resistor-terminal capacitance tests are measured with 2.5V bias on the measured terminal. The remaining resistor terminals are left open circuit. 18 Worst-case supply current consumed when input logic level at 2.4V, standard characteristic of CMOS logic. 19 P DI SS is calculated from (IDDxVDD). CMOS logic level inputs result in minimum power dissipation. 20 All dynamic characteristics are guaranteed by design and not subject to production test. All dynamic characteristics use VDD=5V. 12 13 Revision 1.0, Oct 2004 Page 4 of 8 Data Sheet AS1500/1/2/3 AS150x - SPECIFICATIONS SD (VDD = 3V10% or 5V10%, VA = VDD, VB = 0V, -40CTA+125C unless otherwise noted.) CK ELECTRICAL CHARACTERISTICS-ALL VERSIONS CS 1 A1 A0 D7 D6 D5 D4 D3 D2 D1 D0 0 1 0 DAC Register 1 0 VD SymTyp Conditions Min 21 Max Unit bol SWITCHING CHARACTERISTICS 22, 23 Input Clock Clock Level t CH , t CL 50 ns Pulsewidth High or Low Data Setup Time t DS 5 ns Data Hold Time t DH 5 ns CSN Setup Time t CSS 10 ns CSN High 10 ns t CSW Pulsewidth CK Fall to CSN Rise t CSH 0 ns Hold Time CSN Rise to Clock 10 ns t CS1 Rise Setup Parameter Table 5: Switching Characteristics Serial-Programming Programming of the AS150x is done via the 3 wire serial interface. The three input signals are serial data input (SDI), clock(CK) and chip select (CS). A programming sequence consists of 10-bit, where the last eight bit contain the code word for the resistor value. The first two bits A1 and A0 have to be low(see Table ). The data is shifted into the internal 10 Bit register with the rising edge of the CK signal. With the rising edge of the CSN signal the data becomes valid and the resistance is updated (see figure 2). A detailed block diagram is shown in figure 3. D6 D5 D4 D3 Data Figure 2: Timing Diagram SDI 1 0 CK CSN tD tD tC 1 0 1 A X or A X or t CS t CS t CL t CS t CS 0 V DD V O UT 0V tS 1% 1% Error Figure 3: Detailed Timing Diagram Detailed Description A1 A0 D7 0 0 MSB V O UT 0V D2 D1 D0 LSB Table 6: Serial data format (16 bits) Rheostat Operation The digital potentiometer family AS150x offers nominal resistor values of 10k, 20 k, 50k and 100k. The resistor has 256 contact points where the wiper can access the resistor. The 8-bit code word determines the position of the wiper and is decoded through an internal logic. The lowest code 00h is related to the terminal B. The resistance is then only determined by the wiper resistance (100). The resistance for the next code 01h is the nominal resistor RAB (10k, 20 k, 50k or 100k) divided through 256 plus the wiper resistor. In case of AS1501 (10k) the total resistance is 39+100=139. Accordingly the resistor for code 02h is 78+100=178. The last code 255h does not connect to terminal A directly (see Figure 5). So the maximum value is 10000 - 39 +100 = 10061. The general formula for the calculation of the resistance R WB is: R WB (Dx)= (Dx)/256R AB + R W 21 22 23 Typicals represent average readings at 25C and VDD=5V. Guaranteed by design and not subject to production test. Resistor-terminal capacitance tests are measured with 2.5V bias on the measured terminal. The remaining resistor terminals are left open circuit. See timing diagram for location of measured values. All input control voltages are specified with t R = t F = 1ns (10% to 90% of VDD) and timed from a voltage level of 1.6V. Switching characteristics are measured using VDD=3V or 5V. To avoid false clocking, a minimum input logic slew rate of 1V/s should be maintained. Revision 1.0, Oct 2004 where R AB is the nominal resistance between terminal A and B, R W is the wiper resistance and D X is the 8-Bit Code word. In Table 7 the resistor values between the wiper and terminal B for AS1501 are given for specific codes D X . In the zero-scale condition the wiper resistance of 100 remains present. Page 5 of 8 Data Sheet AS1500/1/2/3 D X (Dec) R WB ( ) Output State 255 10061 Full Scale 128 5100 Midscale 1 139 1 LSB 0 100 Zero-Scale (Wiper Contact Resistance) RS D7 D6 D5 D4 D3 D2 D1 D0 Table 7: RDAC-Codes WB The maximum current through the wiper and terminal B is 5mA. If the current exceeds this limit the internal switches can degrade or even be damaged. As a mechanical potentiometer the resistance R WA and R W B are totally symmetrical. The relation between them is shown in Figure 4. RDAC LATCH AND DECODE RS W RS B Figure 5: Equivalent RDAC Circuit Voltage Output Operation The AS150x family can easily used in an voltage output mode, where the output voltage is proportional to an applied voltage to a given terminal. When 5V are applied to terminal A and B is set to ground the ouput voltage at the wiper starts at zero volts up to 1LSB less then 5V. One LSB of voltage corresponds to the voltage applied at terminal AB divided through 256 steps of possible wiper settings. The formula is given by RW 75 R WA (D), R WB (D) - % of RS R S =R NOMI NAL / 256 10 RW A 50 25 V W (Dx)= (Dx)/256V AB + V B 0 0 64 12 CODE - 19 Figure 4: R WA and R WB versa Code The resistance RWA is the complimentary resistor to RWB and can be controlled digitally as well. RWA starts at the maximum value of the nominal resistance and is reduced with increasing 8-Bit code words. The formula to calculate RWA is given below: R WA (Dx)= (256 - Dx)/256R AB + R W where R AB is the nominal resistance between terminal A and B, R W is the wiper resistance and D X is the 8-Bit Code word. In Table 8 the resistor values between the wiper and terminal B for AS1501 are given for specific codes D X . D X (Dec) 255 128 1 0 R WA ( ) 89 5050 10011 10050 Output State Full Scale Midscale 1 LSB Zero-Scale 25 where V AB is the voltage applied between terminal A and B, V W is the voltage at the wiper, D X is the 8-Bit Code word and V B is the voltage at terminal B. The temperature drift is significant better than in Rheostat mode, since the temperature coefficient is determined by the internal resistor ratio. Therefore the temperature drift is only 15ppm/C. Applications The digital potentiometer can replace in many applications the analog trimming potentiometer. The digital potentiometer is not sensitive to vibrations and shocks. It has an extremely small form-factor and can be adjusted very fast (e.g. AS1500 has an update rate of 600kHz) Furthermore the temperature drift, resolution and noise are significant better and cannot be achieved with a mechanical trimming potentiometer. Due to the programmability the resistor settings can be stored in the system memory, so that after a power down the exact settings can be recalled easily. All analog signals must remain within 0 to VDD range. For standard potentiometer applications the wiper output can be used directly. In the case of a low impedance load a buffer shall be used. Table 8: RDAC-Codes WA Revision 1.0, Oct 2004 Page 6 of 8 Data Sheet AS1500/1/2/3 Package Information The AS150x family is offered in a 8-pin SOIC package: Revision 1.0, Oct 2004 Page 7 of 8 Data Sheet AS1500/1/2/3 Package Dimensions in Inch and mm (values for N = 8 Pin package are valid): Ordering Information Part AS1500 10k Pin Package Delivery Form 8-pin SOIC Tubes AS1501 20k 8-pin SOIC Tubes AS1502 50k 8-pin SOIC Tubes AS1503 100k 8-pin SOIC Tubes AS1500-T 10k 8-pin SOIC T&R AS1501-T 20k 8-pin SOIC T&R 50k 8-pin SOIC T&R AS1503-T 100k 8-pin SOIC For Pb-free package use suffix `-Z` T&R AS1502-T Resistor Copyright Revision 1.0, Oct 2004 Copyright (c) 2004 austriamicrosystems. Trademarks registered (R). All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. To the best of its knowledge, austriamicrosystems asserts that the information contained in this publication is accurate and correct. Contact austriamicrosystems AG A 8141 Schloss Premstatten, Austria T. +43 (0) 3136 500 0 F. +43 (0) 3136 525 01 info@austriamicrosystems.com Page 8 of 8