AD7520, AD7530, AD7521, AD7531 10-Bit, 12-Bit, Multiplying D/A Converters August 1997 Features Description • AD7520/AD7530, 10-Bit Resolution; 8-Bit, 9-Bit and 10-Bit Linearity The AD7520/AD7530 and AD7521/AD7531 are monolithic, high accuracy, low cost 10-bit and 12-bit resolution, multiplying digital-to-analog converters (DAC). Intersil’ thin-film on CMOS processing gives up to 10-bit accuracy with TTL/CMOS compatible operation. Digital inputs are fully protected against static discharge by diodes to ground and positive supply. • AD7521/AD7531, 12-Bit Resolution; 8-Bit, 9-Bit and 10-Bit Linearity • Low Power Dissipation (Max) . . . . . . . . . . . . . . . .20mW • Low Nonlinearity Tempco at 2ppm of FSR/oC • Current Settling Time to 0.05% of FSR . . . . . . . . 1.0µs • Supply Voltage Range . . . . . . . . . . . . . . . . ±5V to +15V • TTL/CMOS Compatible • Full Input Static Protection • /883B Processed Versions Available Typical applications include digital/analog interfacing, multiplication and division, programmable power supplies, CRT character generation, digitally controlled gain circuits, integrators and attenuators, etc. The AD7530 and AD7531 are identical to the AD7520 and AD7521, respectively, with the exception of output leakage current and feedthrough specifications. Ordering Information LINEARITY (INL, DNL) TEMP. RANGE (oC) AD7520JN, AD7530JN 0.2% (8-Bit) 0 to 70 16 Ld PDIP E16.3 AD7520KN, AD7530KN 0.1% (9-Bit) 0 to 70 16 Ld PDIP E16.3 AD7521JN, AD7531JN 0.2% (8-Bit) 0 to 70 18 Ld PDIP E18.3 PART NUMBER PACKAGE PKG. NO. AD7521KN, AD7531KN 0.1% (9-Bit) 0 to 70 18 Ld PDIP E18.3 AD7520LN, AD7530LN 0.05% (10-Bit) -40 to 85 16 Ld PDIP E16.3 AD7521LN, AD7531LN 0.05% (10-Bit) -40 to 85 18 Ld PDIP E18.3 AD7520JD 0.2% (8-Bit) -25 to 85 16 Ld CERDIP F16.3 AD7520KD 0.1% (9-Bit) -25 to 85 16 Ld CERDIP F16.3 AD7520LD 0.05% (10-Bit) -25 to 85 16 Ld CERDIP F16.3 AD7520SD, AD7520SD/883B 0.2% (8-Bit) -55 to 125 16 Ld CERDIP F16.3 AD7520UD, AD7520UD/883B 0.05% (10-Bit) -55 to 125 16 Ld CERDIP F16.3 Pinouts AD7520, AD7530 (CERDIP, PDIP) TOP VIEW AD7521, AD7531 (PDIP) TOP VIEW IOUT1 1 16 RFEEDBACK IOUT1 1 18 RFEEDBACK IOUT2 2 15 VREF IOUT2 2 17 VREF GND 3 BIT 1 (MSB) 4 14 V+ 13 BIT 10 (LSB) GND 3 16 V+ BIT 1 (MSB) 4 15 BIT 12 (LSB) BIT 2 5 12 BIT 9 BIT 2 5 14 BIT 11 BIT 3 6 11 BIT 8 BIT 3 6 13 BIT 10 BIT 4 7 10 BIT 7 BIT 4 7 12 BIT 9 BIT 5 8 9 BIT 6 BIT 5 8 11 BIT 8 BIT 6 9 10 BIT 7 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. http://www.intersil.com or 407-727-9207 | Copyright © Intersil Corporation 1999 10-7 File Number 3104.1 AD7520, AD7530, AD7521, AD7531 Absolute Maximum Ratings Thermal Information Supply Voltage (V+ to GND). . . . . . . . . . . . . . . . . . . . . . . . . . . +17V VREF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±25V Digital Input Voltage Range . . . . . . . . . . . . . . . . . . . . . . . V+ to GND Output Voltage Compliance . . . . . . . . . . . . . . . . . . . . -100mV to V+ Thermal Resistance (Typical, Note 1) θJA (oC/W) θJC (oC/W) 16 Ld PDIP Package . . . . . . . . . . . . . . . . 100 N/A 18 Ld PDIP Package . . . . . . . . . . . . . . . . 90 N/A CERDIP Package . . . . . . . . . . . . . . . . . . 75 20 Maximum Junction Temperature (Hermetic Package) . . . . . . . . 175oC Maximum Junction Temperature (Plastic Packages) . . . . . . . 150oC Maximum Storage Temperature Range . . . . . . . . . .-65oC to 150oC Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300oC Operating Conditions Temperature Ranges JN, KN, LN Versions . . . . . . . . . . . . . . . . . . . . . . . . . .0oC to 70oC JD, KD, LD Versions . . . . . . . . . . . . . . . . . . . . . . . . -25oC to 85oC SD, UD Versions . . . . . . . . . . . . . . . . . . . . . . . . . . -55oC to 125oC CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. The digital control inputs are zener protected; however, permanent damage may occur on unconnected units under high energy electrostatic fields. Keep unused units in conductive foam at all times. Do not apply voltages higher than VDD or less than GND potential on any terminal except VREF and RFEEDBACK. NOTE: 1. θJA is measured with the component mounted on an evaluation PC board in free air. Electrical Specifications V+ = +15V, VREF = +10V, TA = 25oC Unless Otherwise Specified AD7520/AD7530 PARAMETER TEST CONDITIONS MIN TYP AD7521/AD7531 MAX MIN TYP MAX UNITS SYSTEM PERFORMANCE (Note 2) Resolution 10 10 10 12 12 12 Bits J, S S Over -55oC to 125oC (Notes 2, 5) (Figure 3) - - ±0.2 (8-Bit) - - ±0.2 (8-Bit) % of FSR K T Over -55oC to 125oC (Figure 2) - - ±0.1 (9-Bit) - - ±0.1 (9-Bit) % of FSR L, U -10V ≤ VREF ≤ +10V U Over -55oC to 125oC (Figure 2) - - ±0.05 (10-Bit) - - ±0.05 (10-Bit) % of FSR -10V ≤ VREF ≤ +10V (Notes 3, 4) - - ±2 - - ±2 ppm of FSR/oC Gain Error - ±0.3 - - ±0.3 - % of FSR Gain Error Tempco - - ±10 - - ±10 ppm of FSR/oC Over the Specified Temperature Range - - ±200 (±300) - - ±200 (±300) nA Output Current Settling Time To 0.05% of FSR (All Digital Inputs Low To High And High To Low) (Note 4) (Figure 7) - 1.0 - - 1.0 - µs Feedthrough Error VREF = 20VP-P , 10kHz (50kHz) All Digital Inputs Low (Note 4) (Figure 6) - - 10 - - 10 mVP-P All Digital Inputs High IOUT1 at Ground 5 10 20 5 10 20 kΩ IOUT1 All Digital Inputs High (Note 4) (Figure 5) IOUT2 - 200 - - 200 - pF - 75 - - 75 - pF - 75 - - 75 - pF - 200 - - 200 - pF Nonlinearity Nonlinearity Tempco Output Leakage Current (Either Output) DYNAMIC CHARACTERISTICS REFERENCE INPUT Input Resistance ANALOG OUTPUT Output Capacitance IOUT1 All Digital Inputs Low (Note 4) (Figure 5) IOUT2 10-8 AD7520, AD7530, AD7521, AD7531 V+ = +15V, VREF = +10V, TA = 25oC Unless Otherwise Specified (Continued) Electrical Specifications AD7520/AD7530 PARAMETER TEST CONDITIONS Output Noise AD7521/AD7531 MIN TYP MAX MIN TYP MAX UNITS Both Outputs (Note 4) (Figure 4) - Equivalent to 10kΩ - - Equivalent to 10kΩ - Johnson Noise Over the Specified Temperature Range VIN = 0V or +15V - - 0.8 - - 0.8 V 2.4 - - 2.4 - - V - - ±1 - - ±1 µA ±0.005 - % FSR/ % ∆V+ DIGITAL INPUTS Low State Threshold, VIL High State Threshold, VIH Input Current, IIL, IIH Input Coding See Tables 1 and 2 Binary/Offset Binary POWER SUPPLY CHARACTERISTICS Power Supply Rejection V+ = 14.5V to 15.5V (Note 3) (Figure 3) - Power Supply Voltage Range ±0.005 - - +5 to +15 I+ Total Power Dissipation +5 to +15 V All Digital Inputs at 0V or V+ Excluding Ladder Network - ±1 - - ±1 - µA All Digital Inputs High or Low Excluding Ladder Network - - 2 - - 2 mA Including the Ladder Network - 20 - - 20 - mW NOTES: 2. Full scale range (FSR) is 10V for Unipolar and ±10V for Bipolar modes. 3. Using internal feedback resistor RFEEDBACK . 4. Guaranteed by design, or characterization and not production tested. 5. Accuracy not guaranteed unless outputs at GND potential. 6. Accuracy is tested and guaranteed at V+ = 15V only. Functional Diagram 10kΩ VREF 20kΩ 10kΩ 20kΩ 10kΩ 20kΩ 10kΩ 20kΩ 20kΩ 20kΩ GND SPDT NMOS SWITCHES IOUT2 IOUT1 10kΩ MSB BIT 2 BIT 3 NOTES: Switches shown for Digital Inputs “High”. Resistor values are typical. 10-9 RFEEDBACK AD7520, AD7530, AD7521, AD7531 Pin Descriptions AD7520/30 AD7521/31 PIN NAME DESCRIPTION 1 1 IOUT1 2 2 IOUT2 Current Out summing junction of the R2R ladder network. Current Out virtual ground, return path for the R2R ladder network. 3 3 GND Digital Ground. Ground potential for digital side of D/A. 4 4 5 5 Bit 2 Digital Bit 2. 6 6 Bit 3 Digital Bit 3. 7 7 Bit 4 Digital Bit 4. 8 8 Bit 5 Digital Bit 5. Bits 1(MSB) Most Significant Digital Data Bit. 9 9 Bit 6 Digital Bit 6. 10 10 Bit 7 Digital Bit 7. 11 11 Bit 8 Digital Bit 8. 12 12 Bit 9 Digital Bit 9. 13 13 Bit 10 Digital Bit 10 (AD7521/31). Least Significant Digital Data Bit (AD7520/30). - 14 Bit 11 Digital Bit 11 (AD7521/31). - 15 Bit 12 14 16 V+ 15 17 16 18 VREF Least Significant Digital Data Bit (AD7521/31). Power Supply +5V to +15V. Voltage Reference Input to set the output range. Supplies the R2R resistor ladder. RFEEDBACK Feedback resistor used for the current to voltage conversion when using an external Op Amp. Definition of Terms Nonlinearity: Error contributed by deviation of the DAC transfer function from a “best straight line” through the actual plot of transfer function. Normally expressed as a percentage of full scale range or in (sub)multiples of 1 LSB. Resolution: It is addressing the smallest distinct analog output change that a D/A converter can produce. It is commonly expressed as the number of converter bits. A converter with resolution of n bits can resolve output changes of 2-N of the full-scale range, e.g., 2-N VREF for a unipolar conversion. Resolution by no means implies linearity. Settling Time: Time required for the output of a DAC to settle to within specified error band around its final value (e.g., 1/ LSB) for a given digital input change, i.e., all digital inputs 2 LOW to HIGH and HIGH to LOW. Gain Error: The difference between actual and ideal analog output values at full scale range, i.e., all digital inputs at HIGH state. It is expressed as a percentage of full scale range or in (sub)multiples of 1 LSB. Feedthrough Error: Error caused by capacitive coupling from VREF to IOUT1 with all digital inputs LOW. Output Capacitance: Capacitance from IOUT1 and IOUT2 terminals to ground. or current reference and an operational amplifier are all that is required for most voltage output applications. A simplified equivalent circuit of the DAC is shown in the Functional Diagram. The NMOS SPDT switches steer the ladder leg currents between IOUT1 and IOUT2 buses which must be held either at ground potential. This configuration maintains a constant current in each ladder leg independent of the input code. Converter errors are further reduced by using separate metal interconnections between the major bits and the outputs. Use of high threshold switches reduce offset (leakage) errors to a negligible level. The level shifter circuits are comprised of three inverters with positive feedback from the output of the second to the first, see Figure 1. This configuration results in TTL/CMOS compatible operation over the full military temperature range. With the ladder SPDT switches driven by the level shifter, each switch is binarily weighted for an ON resistance proportional to the respective ladder leg current. This assures a constant voltage drop across each switch, creating equipotential terminations for the 2R ladder resistors and highly accurate leg currents. V+ 1 3 Output Leakage Current: Current which appears on IOUT1 terminal when all digital inputs are LOW or on IOUT2 terminal when all digital inputs are HIGH. 4 6 TO LADDER 8 9 Detailed Description The AD7520, AD7530, AD7521 and AD7531 are monolithic, multiplying D/A converters. A highly stable thin film R-2R resistor ladder network and NMOS SPDT switches form the basis of the converter circuit, CMOS level shifters permit low power TTL/CMOS compatible operation. An external voltage DTL/TTL/ CMOS INPUT 10-10 2 5 7 IOUT2 IOUT1 FIGURE 1. CMOS SWITCH AD7520, AD7530, AD7521, AD7531 Test Circuits The following test circuits apply for the AD7520. Similar circuits are used for the AD7530, AD7521 and AD7531. VREF +15V BIT 1 (MSB) 10-BIT BINARY COUNTER RFEEDBACK 4 15 16 IOUT1 1 5 AD7520 HA2600 I BIT 10 13 3 2 OUT2 + (LSB) +15V 10kΩ 0.01% 1MΩ GND CLOCK BIT 1 (LSB) BIT 11 +10V 10kΩ 0.01% 12-BIT REFERENCE DAC HA2600 + LINEARITY ERROR X 100 BIT 10 (LSB) BIT 12 500kΩ BIT 1 (MSB) - VREF BIT 10 VREF UNGROUNDED SINE WAVE GENERATOR 400Hz 1VP-P 5K 0.01% 5kΩ 0.01% 15 14 RFEEDBACK 4 16 I OUT1 1 5 AD7520 I OUT2 HA2600 13 3 2 + HA2600 + GND FIGURE 2. NONLINEARITY FIGURE 3. POWER SUPPLY REJECTION +11V (ADJUST FOR VOUT = 0V) +15V 1K f = 1kHz BW = 1Hz 15µF 100Ω 15 14 IOUT2 4 2 5 AD7520 IOUT1 13 3 1 NC +15V +15V 10kΩ QUAN TECH MODEL 134D 101ALN WAVE VOUT ANALYZER + BIT 1 (MSB) - 1kΩ 50kΩ 50V BIT 10 (LSB) 0.1µF FIGURE 4. NOISE VREF = 20VP-P 100kHz SINE WAVE +15V BIT 1 (MSB) 15 14 4 16 5 AD7520 1 BIT 10 (LSB) 2 NC 1kΩ 100mVP-P 1MHz SCOPE FIGURE 5. OUTPUT CAPACITANCE -10V 13 3 15 14 4 16 5 AD7520 1 13 3 2 VREF BIT 1 (MSB) IOUT1 3 IOUT2 6 HA2600 2 + +5V 0V VOUT DIGITAL INPUT BIT 10 (LSB) GND 5t: 1% SETTLING (1mV) EXTRAPOLATE 8t: 0.03% SETTLING t = RISE TIME +15V 15 14 4 5 AD7520 1 13 3 2 SCOPE +100mV IOUT2 100Ω GND FIGURE 6. FEEDTHROUGH ERROR FIGURE 7. OUTPUT CURRENT SETTLING TIME 10-11 AD7520, AD7530, AD7521, AD7531 Applications “Digital Input Code/Analog Output Value” table for bipolar mode is given in Table 2. Unipolar Binary Operation +15V BIT 1 (MSB) DIGITAL INPUT BIT 10 (LSB) BIT 10 (LSB) 15 14 4 16 5 AD7520 1 13 3 2 10MΩ 15 14 RFEEDBACK 4 16 5 IOUT1 AD7520 1 13 3 2 IOUT2 - - R1 10K R2 10K 0.01% 0.01% 6 + VOUT BIT 1 (MSB) +15V VREF R3 VREF DIGITAL INPUT The circuit configuration for operating the AD7520 in unipolar mode is shown in Figure 8. Similar circuits can be used for AD7521, AD7530 and AD7531. With positive and negative VREF values the circuit is capable of 2-Quadrant multiplication. The “Digital Input Code/Analog Output Value” table for unipolar mode is given in Table 1. 6 + RFEEDBACK IOUT1 6 + IOUT2 VOUT FIGURE 9. BIPOLAR OPERATION (4-QUADRANT MULTIPLICATION) TABLE 2. BlPOLAR (OFFSET BINARY) CODE TABLE GND DIGITAL INPUT FIGURE 8. UNIPOLAR BINARY OPERATION (2-QUADRANT MULTIPLICATION) TABLE 1. CODE TABLE - UNlPOLAR BINARY OPERATION DIGITAL INPUT ANALOG OUTPUT 1111111111 -VREF (1-2-N) 1000000001 -VREF (1/2 + 2-N) 1000000000 -VREF/2 0111111111 -VREF (1/2-2-N) 0000000001 -VREF (2-N) 0000000000 0 ANALOG OUTPUT 1111111111 -VREF (1-2-(N-1)) 1000000001 -VREF (2-(N-1)) 1000000000 0 0111111111 VREF (2-(N-1)) 0000000001 VREF (1-2-(N-1)) 0000000000 VREF NOTES: 1. LSB = 2-(N-1) VREF . 2. N = 10 for 7520, 7521; N = 12 for 7530, 7531. A “Logic 1” input at any digital input forces the corresponding ladder switch to steer the bit current to IOUT1 bus. A “Logic 0” input forces the bit current to IOUT2 bus. For any code the IOUT1 and IOUT2 bus currents are complements of one another. The current amplifier at IOUT2 changes the polarity of IOUT2 current and the transconductance amplifier at IOUT1 output sums the two currents. This configuration doubles the output range. The difference current resulting at zero offset binary code, (MSB = “Logic 1”, All other bits = “Logic 0”), is corrected by using an external resistor, (10MΩ), from VREF to IOUT2 . NOTES: 1. LSB = 2-N VREF . 2. N = 10 for 7520, 7530; N = 12 for 7521, 7531. Zero Offset Adjustment 1. Connect all digital inputs to GND. Offset Adjustment 2. Adjust the offset zero adjust trimpot of the output operational amplifier for 0V at VOUT . 1. Adjust VREF to approximately +10V. 2. Connect all digital inputs to “Logic 1”. Gain Adjustment 3. Adjust IOUT2 amplifier offset adjust trimpot for 0V ±1mV at IOUT2 amplifier output. 1. Connect all digital inputs to V+. 2. Monitor VOUT for a -VREF (1-2-N) reading. (N = 10 for AD7520/30 and N = 12 for AD7521/31). 4. Connect MSB (Bit 1) to “Logic 1” and all other bits to “Logic 0”. 3. To decrease VOUT , connect a series resistor (0 to 250Ω) between the reference voltage and the VREF terminal. 4. To increase VOUT , connect a series resistor (0 to 250Ω) in the IOUT1 amplifier feedback loop. Bipolar (Offset Binary) Operation The circuit configuration for operating the AD7520 in the bipolar mode is given in Figure 9. Similar circuits can be used for AD7521, AD7530 and AD7531. Using offset binary digital input codes and positive and negative reference voltage values, 4-Quadrant multiplication can be realized. The 5. Adjust IOUT1 amplifier offset adjust trimpot for 0V ±1mV at VOUT. Gain Adjustment 1. Connect all digital inputs to V+. 2. Monitor VOUT for a -VREF (1-2-(N-1) volts reading. (N = 10 for AD7520 and AD7530, and N = 12 for AD7521 and AD7531). 3. To increase VOUT , connect a series resistor of up to 250Ω between VOUT and RFEEDBACK . 4. To decrease VOUT , connect a series resister of up to 250Ω between the reference voltage and the VREF terminal. 10-12 AD7520, AD7530, AD7521, AD7531 Die Characteristics DIE DIMENSIONS: PASSIVATION: 101 mils x 103 mils (2565micrms x 2616micrms) Type: PSG/Nitride PSG: 7 ±1.4kÅ Nitride: 8 ±1.2kÅ METALLIZATION: Type: Pure Aluminum Thickness: 10 ±1kÅ PROCESS: CMOS Metal Gate Metallization Mask Layout AD7520, AD7530 PIN 7 BIT 4 PIN 6 BIT 3 PIN 5 BIT 2 PIN 4 BIT 1 (MSB) PIN 3 GND PIN 2 IOUT2 PIN 8 BIT 5 PIN 1 IOUT1 PIN 9 BIT 6 PIN 10 BIT 7 PIN 16 RFEEDBACK PIN 11 BIT 8 PIN 15 VREF PIN 14 V+ PIN 12 BIT 9 NC PIN 13 BIT 10 (LSB) 10-13 NC AD7520, AD7530, AD7521, AD7531 Die Characteristics DIE DIMENSIONS: PASSIVATION: 101 mils x 103 mils (2565micrms x 2616micrms) Type: PSG/Nitride PSG: 7 ±1.4kÅ Nitride: 8 ±1.2kÅ METALLIZATION: Type: Pure Aluminum Thickness: 10 ±1kÅ PROCESS: CMOS Metal Gate Metallization Mask Layout AD7521, AD7531 PIN 7 BIT 4 PIN 6 BIT 3 PIN 5 BIT 2 PIN 4 BIT 1 (MSB) PIN 3 GND PIN 2 IOUT2 PIN 8 BIT 5 PIN 1 IOUT1 PIN 9 BIT 6 PIN 10 BIT 7 PIN 18 RFEEDBACK PIN 11 BIT 8 PIN 17 VREF PIN 16 V+ PIN 12 BIT 9 PIN 13 BIT 10 PIN 14 BIT 11 10-14 PIN 15 BIT 12 (LSB) AD7520, AD7530, AD7521, AD7531 All Intersil semiconductor products are manufactured, assembled and tested under ISO9000 quality systems certification. Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries. For information regarding Intersil Corporation and its products, see web site http://www.intersil.com Sales Office Headquarters NORTH AMERICA Intersil Corporation P. O. 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