® DAC715 DAC FPO 715 DAC 715 16-BIT DIGITAL-TO-ANALOG CONVERTER with 16-Bit Bus Interface FEATURES DESCRIPTION ● HIGH-SPEED 16-BIT PARALLEL DOUBLEBUFFERED INTERFACE The DAC715 is a complete monolithic digital-toanalog converter including a +10V temperature compensated reference, current-to-voltage amplifier, 16-bit parallel interface that is double buffered, and an asynchronous clear function which immediately sets the output voltage to one-half of full-scale. ● VOLTAGE OUTPUT: 0 to +10V ● 13-, 14-, 15-BIT LINEARITY GRADES ● 16-BIT MONOTONIC OVER TEMPERATURE (L GRADE) ● POWER DISSIPATION: 600mW max The output voltage range is 0 to +10V while operating from ±12V or ±15V supplies. The gain and bipolar offset adjustments are designed so that they can be set via external potentiometers or external D/A converters. The output amplifier is protected against short circuit to ground. ● GAIN AND OFFSET ADJUST: Convenient for Auto-Cal D/A Converters ● 28-LEAD DIP AND SOIC PACKAGES The 28-pin DAC715 is available in a 0.3" plastic DIP and wide-body plastic SOIC package. The DAC715P, U, PB, and UB are specified over the –40°C to +85°C temperature range while the DAC715PK, UK, PL, and UL are specified over the 0°C to +70°C range. D0 D15 A1 Input Latch A0 16 WR CLR D/A Latch 16 Reference Circuit Gain Adjust 16-Bit D/A Converter VOUT VREF OUT +10V Offset Adjust International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111 Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 © 1995 Burr-Brown Corporation PDS-1306D Printed in U.S.A. July, 1997 SPECIFICATIONS ELECTRICAL At TA = +25°C, VCC = ±15V, and after a 10-minute warm-up, unless otherwise noted. DAC715P, U PARAMETER MIN TYP DAC715PB, UB MAX MIN TYP DAC715PK, UK MAX MIN TYP DAC715PL, UL MAX MIN TYP MAX UNITS ✻ Bits ✻ ✻ ✻ ✻ V V µA µA ±2 ±2 ±1 ±1 LSB LSB LSB LSB Bits % % % FSR(2) % FSR % FSR/%VCC PPM FSR/%VCC INPUT RESOLUTION ✻ 16 DIGITAL INPUTS Input Code Logic Levels(1): VIH V IL IIH (V I = +2.7V) IIL (VI = +0.4V) Binary Two’s Complement +2.0 +VCC – 1.4 0 +0.8 ±10 ±10 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ TRANSFER CHARACTERISTICS ACCURACY Linearity Error TMIN to TMAX Differential Linearity Error TMIN to TMAX Monotonicity Over Temp Gain Error(3) TMIN to TMAX Offset Error(3) TMIN to TMAX Power Supply Sensitivity Of Full Scale ±4 ±8 ±4 ±8 13 DYNAMIC PERFORMANCE Settling Time (to ±0.003%FSR, 5kΩ ll 500pF Load)(4) 10V Output Step 1 LSB Output Step(5) Output Slew Rate Total Harmonic Distortion + Noise 0dB, 1001Hz, fS = 100kHz –20dB, 1001Hz, fS = 100kHz –60dB, 1001Hz, fS = 100kHz SINAD 1001Hz, fS = 100kHz Digital Feedthrough(5) Digital-to-Analog Glitch Impulse(5) Output Noise Voltage (includes Reference) ANALOG OUTPUT Output Voltage Range +VCC, –VCC = ±11.4V Output Current Output Impedance Short Circuit to ACOM Duration ±0.1 ±0.2 ±0.1 ±0.2 ±0.003 ±30 6 4 10 POWER SUPPLY REQUIREMENTS Voltage: +VCC –VCC Current (no load, ±15V Supplies) +VCC –VCC Power Dissipation +9.975 +9.960 14 ±2 ±2 ±2 ±2 15 16 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ % % % 87 2 15 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ dB nV-s nV-s 120 ✻ ✻ ✻ nV√Hz V mA Ω ✻ ✻ ✻ ✻ ✻ ✻ 0.1 ✻ ✻ ✻ Indefinite ✻ ✻ ✻ +10.000 +10.025 +10.040 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ 1 +16.5 –11.4 13 22 525 15 25 600 ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ V V Ω mA ✻ ✻ ✻ ✻ V V ✻ ✻ ✻ ✻ ✻ ✻ mA mA mW ✻ ✻ °C °C ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ +15 –15 ✻ ✻ ✻ Indefinite ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ ✻ TEMPERATURE RANGE Specification All Grades –40 –60 Storage Thermal Resistance θJA DIP Package SOIC Package µs µs V/µs 0.005 0.03 3.0 2 +11.4 –16.5 ±0.1 ±0.15 ✻ ✻ ✻ ✻ ✻ ✻ ✻ 10 0 to +10 ±5 REFERENCE VOLTAGE Voltage TMIN to TMAX Output Resistance Source Current Short Circuit to ACOM, Duration ±2 ±4 ±2 ±4 +85 +150 75 75 ✻ ✻ ✻ ✻ ✻ ✻ 0 ✻ +70 ✻ ✻ ✻ ✻ ✻ ✻ ✻ °C/W °C/W ✻ Specifications are the same as grade to the left. NOTES: (1) Digital inputs are TTL and +5V CMOS compatible over the specification temperature range. (2) FSR means Full Scale Range. For example, for a 0 to +10V output, FSR = 10V. (3) Errors externally adjustable to zero. (4) Maximum represents greater than the 3σ limit. Not 100% tested for this parameter. (5) For the worst case code changes: FFFFH to 0000H and 0000H to FFFFH. These are Binary Two’s Complement (BTC) codes. (6) Typical supply voltages times maximum currents. ® DAC715 2 ABSOLUTE MAXIMUM RATINGS(1) TIMING DIAGRAM +VCC to COMMON ...................................................................... 0V, +17V –VCC to COMMON ...................................................................... 0V, –17V +VCC to –VCC ........................................................................................................................... 34V Digital Inputs to COMMON ..................................................... –1V to +VCC External Voltage Applied to BPO and Range Resistors ..................... ±VCC VREF OUT ...................................................... Indefinite Short to COMMON VOUT ............................................................ Indefinite Short to COMMON Power Dissipation .......................................................................... 750mW Storage Temperature ...................................................... –60°C to +150°C Lead Temperature (soldering, 10s) ................................................ +300°C tAW tAH A0, A1 tDW D0-D15 tDH NOTE: (1) Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to absolute maximum conditions for extended periods may affect device reliability. WR tWP PACKAGE INFORMATION TIMING SPECIFICATIONS PRODUCT PACKAGE PACKAGE DRAWING NUMBER(1) DAC715P DAC715U DAC715PB DAC715UB DAC715PK DAC715UK DAC715PL DAC715UL Plastic DIP Plastic SOIC Plastic DIP Plastic SOIC Plastic DIP Plastic SOIC Plastic DIP Plastic SOIC 246 217 246 217 246 217 246 217 TA = –40°C to +85°C, +VCC = +12V or +15V, –VCC = –12V or –15V. SYMBOL tDW tAW tAH tDH tWP(1) tCP PARAMETER MIN Data Valid to End of WR A0, A1 Valid to End of WR A0, A1 Hold after End of WR Data Hold after end of WR Write Pulse Width CLEAR Pulse Width 50 50 10 10 50 200 MAX UNITS ns ns ns ns ns ns NOTES: (1) For single-buffered operation, tWP is 80ns min. Refer to page 10. NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. TRUTH TABLE ORDERING INFORMATION PRODUCT PACKAGE TEMPERATURE RANGE DIFFERENTIAL LINEARITY ERROR MAX at +25°C DAC715P DAC715U DAC715PB DAC715UB DAC715PK DAC715UK DAC715PL DAC715UL Plastic DIP Plastic SOIC Plastic DIP Plastic SOIC Plastic DIP Plastic SOIC Plastic DIP Plastic SOIC –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C 0°C to 70°C 0°C to 70°C 0°C to 70°C 0°C to 70°C ±4LSB ±4LSB ±2LSB ±2LSB ±2LSB ±2LSB ±1LSB ±1LSB A0 A1 WR CLR DESCRIPTION 0 1 1 0 X X 1 0 1 0 X X 1→0→1 1→0→1 1→0→1 0 1 X 1 1 1 1 1 0 Load Input Latch Load D/A Latch No Change Latches Transparent No Change Reset D/A Latch ELECTROSTATIC DISCHARGE SENSITIVITY Electrostatic discharge can cause damage ranging from performance degradation to complete device failure. Burr-Brown Corporation recommends that all integrated circuits be handled and stored using appropriate ESD protection methods. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet published specifications. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. ® 3 DAC715 PIN CONFIGURATION PIN DESCRIPTIONS DCOM 1 28 D0 (LSB) ACOM 2 27 D1 VOUT 3 26 D2 Offset Adjust 4 25 D3 VREF OUT 5 24 D4 Gain Adjust 6 23 D5 +VCC 7 22 D6 –VCC 8 21 D7 CLR 9 20 D8 WR 10 19 D9 A1 11 18 D10 A0 12 17 D11 D15 (MSB) 13 16 D12 D14 14 15 D13 DAC715 ® DAC715 4 PIN LABEL 1 2 3 4 5 6 7 8 9 DCOM ACOM VOUT Offset Adjust VREF OUT Gain Adjust +VCC –VCC CLR 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 WR A1 A0 D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 DESCRIPTION Digital Ground Analog Ground 0 to +10V D/A Output Offset Adjust Voltage Reference Output Gain Adjust +12V to +15V Supply –12V to –15V Supply CLEAR. Sets D/A output to Half Scale (Active Low) Write (Active Low) Enable for D/A latch (Active Low) Enable for Input latch (Active Low) Data Bit 15 (Most Significant Bit) Data Bit 14 Data Bit 13 Data Bit 12 Data Bit 11 Data Bit 10 Data Bit 9 Data Bit 8 Data Bit 7 Data Bit 6 Data Bit 5 Data Bit 4 Data Bit 3 Data Bit 2 Data Bit 1 Data Bit 0 (Least Significant Bit) TYPICAL PERFORMANCE CURVES POWER SUPPLY REJECTION vs POWER SUPPLY RIPPLE FREQUENCY LOGIC vs V LEVEL 1k 2.0 –VCC 100 1.0 I Digital Input (µA) [Change in FSR]/[Change in Supply Voltage] (ppm of FSR/ %) At TA = +25°C, and VCC = ±15V, unless otherwise noted. +VCC 10 CLR 0 DATA –1.0 1 –2.0 –0.85 0.1 10 100 1k 10k 100k WR, A0, A1 1M 0 0.85 1.7 2.55 3.4 4.25 5.1 5.95 6.8 V Digital Input Frequency (Hz) FULL-SCALE OUTPUT SWING SETTLING TIME, +10V TO 0V VOUT (V) ∆ Around 0V (µV) 2000 +5V 1500 0V WR (V) 2500 1000 500 0 –500 –1000 –1500 –2000 –2500 Time (10µs/div) Time (1µs/div) Spectral Noise Density SETTLING TIME, 0V TO +10V 1000 +5V 1500 0V WR 2000 1000 100 nV/√Hz ∆ Around +10V (µV) 2500 500 0 –500 10 –1000 –1500 –2000 1 –2500 1 Time (1µs/div) 10 100 1k 10k 100k 1M 10M Frequency (Hz) ® 5 DAC715 DISCUSSION OF SPECIFICATIONS DIGITAL FEEDTHROUGH When the D/A is not selected, high frequency logic activity on the digital inputs is coupled through the device and shows up as output noise. This noise is digital feedthrough. LINEARITY ERROR Linearity error is defined as the deviation of the analog output from a straight line drawn between the end points of the transfer characteristic. OPERATION The DAC715 is a monolithic integrated-circuit 16-bit D/A converter complete with 16-bit D/A switches and ladder network, voltage reference, output amplifier and microprocessor bus interface. DIFFERENTIAL LINEARITY ERROR Differential linearity error (DLE) is the deviation from 1LSB of an output change from one adjacent state to the next. A DLE specification of ±1/2LSB means that the output step size can range from 1/2LSB to 3/2LSB when the digital input code changes from one code word to the adjacent code word. If the DLE is more positive than –1LSB, the D/A is said to be monotonic. INTERFACE LOGIC The DAC715 has double-buffered data latches. The input data latch holds a 16-bit data word before loading it into the second latch, the D/A latch. This double-buffered organization permits simultaneous update of several D/A converters. All digital control inputs are active low. Refer to the block diagram shown in Figure 1. MONOTONICITY A D/A converter is monotonic if the output either increases or remains the same for increasing digital input values. Monotonicity of DAC715 is guaranteed over the specification temperature range to 13-, 14-, 15-, and 16-bits for performance grades DAC715P/U, DAC715PB/UB, DAC715PK/UK, and DAC715PL/UL respectively. All latches are level-triggered. Data present when the enable inputs are logic “0” will enter the latch. When the enable inputs return to logic “1”, the data is latched. The CLR input resets both the input latch and the D/A latch to give a half scale output. SETTLING TIME LOGIC INPUT COMPATIBILITY Settling time is the total time (including slew time) for the D/A output to settle to within an error band around its final value after a change in input. Settling times are specified to within ±0.003% of Full Scale Range (FSR) for an output step change of 10V and 1LSB. The 1LSB change is measured at the Major Carry (FFFFH to 0000H, and 0000H to FFFFH: BTC codes), the input transition at which worst-case settling time occurs. The DAC715 digital inputs are TTL compatible (1.4V switching level), low leakage, and high impedance. Thus the inputs are suitable for being driven by any type of 5V logic family, such as CMOS logic. An equivalent circuit for the digital inputs is shown in Figure 2. The inputs will float to logic “0” if left unconnected. It is recommended that any unused inputs be connected to DCOM to improve noise immunity. Digital inputs remain high impedance when power is off. TOTAL HARMONIC DISTORTION Total harmonic distortion is defined as the ratio of the square root of the sum of the squares of the values of the harmonics to the value of the fundamental frequency. It is expressed in % of the fundamental frequency amplitude at sampling rate fS. INPUT CODING The DAC715 is designed to accept binary two’s complement (BTC) input codes. For unipolar analog output configuration, a digital input of 7FFFH gives a full scale output, 8000H gives a zero output, and 0000H gives half scale output. SIGNAL-TO-NOISE AND DISTORTION RATIO (SINAD) SINAD includes all the harmonic and outstanding spurious components in the definition of output noise power in addition to quantizing and internal random noise power. SINAD is expressed in dB at a specified input frequency and sampling rate, fS. INTERNAL REFERENCE The DAC715 contains a +10V reference. The reference output may be used to drive external loads, sourcing up to 2mA. The load current should be constant, otherwise the gain of the converter will vary. OUTPUT VOLTAGE SWING The output amplifier of the DAC715 is committed to a 0 to +10V output range. It will provide a 0 to +10V output swing while operating on ±11.4V or higher voltage supplies. DIGITAL-TO-ANALOG GLITCH IMPULSE The amount of charge injected into the analog output from the digital inputs when the inputs change state. It is measured at half scale at the input codes where as many as possible switches change state—from FFFFH to 0000H. ® DAC715 6 Gain Adjust VREF OUT +VCC – VCC 6 5 7 8 170Ω +10V Reference 15kΩ 4 Offset Adjust 3 VOUT 10kΩ +2.5V 5kΩ –VCC D/A Switches CLR 9 A1 11 A0 12 WR 10 16-Bit D/A Latch 16-Bit Input Latch 28 27 26 25 24 23 22 21 20 19 18 17 16 15 D0 LSB 14 13 2 1 D15 ACOM MSB DCOM FIGURE 1. DAC715 Block Diagram. Range of Gain Adjust ≈ ±0.3% + Full Scale +VCC ESD Protection Circuit R Digital Input 6.8V Full Scale Range Analog Output R = 1kΩ: A0, A1, WR, CLR 3kΩ: D0...D15 Gain Adjust Rotates the Line 5pF –VCC Range of Offset Adjust Offset Adj. Translates the Line ≈ ±0.3% FIGURE 2. Equivalent Circuit of Digital Inputs. 8000H Zero 0000H 7FFFH Digital Input FIGURE 3. Relationship of Offset and Gain Adjustments. GAIN AND OFFSET ADJUSTMENTS Figure 3 illustrates the relationship of offset and gain adjustments for a unipolar connected D/A converter. Offset should be adjusted first to avoid interaction of adjustments. See Table I for calibration values and codes. These adjustments have a minimum range of ±0.3%. Offset Adjustment Apply the digital input code that produces zero output voltage and adjust the offset potentiometer or the offset adjust D/A converter for 0V. ® 7 DAC715 DAC715 CALIBRATION VALUES 1 LEAST SIGNIFICANT BIT = 152µV DIGITAL INPUT CODE BINARY TWO’S COMPLEMENT, BTC ANALOG OUTPUT (V) DESCRIPTION 7FFFH | 4000H | 0001H 9.999847 Full Scale –1LSB 7.5 3/4 Scale 5.000152 Half Scale + 1LSB 0000H 5 Half Scale 1 DCOM 28 2 ACOM 27 3 VOUT 26 4 5 FFFFH | C000H | 8000H 4.999847 1/4 Scale 0 Zero VREF OUT 6 24 23 +12V to +15V 7 +VCC 22 8 –VCC 21 –12V to –15V Half Scale – 1LSB 2.5 25 0.01µF + 0.01µF TABLE I. Digital Input and Analog Output Voltage Calibration Values. Gain Adjustment Apply the digital input that gives the maximum positive voltage output. Adjust the gain potentiometer or the gain adjust D/A converter for this positive full scale voltage. + 9 20 10 19 11 18 12 17 13 16 14 15 FIGURE 4. Power Supply Connections. well as at +VCC. The capacitors should be located close to the package. The DAC715 has separate ANALOG COMMON and DIGITAL COMMON pins. The current through DCOM is mostly switching transients and are up to 1mA peak in amplitude. The current through ACOM is typically 5µA for all codes. INSTALLATION GENERAL CONSIDERATIONS Due to the high-accuracy of the DAC715, system design problems such as grounding and contact resistance become very important. A 16-bit converter with a 10V full-scale range has a 1LSB value of 152µV. With a load current of 5mA, series wiring and connector resistance of only 60mΩ will cause a voltage drop of 300µV. To understand what this means in terms of a system layout, the resistivity of a typical 1 ounce copper-clad printed circuit board is 1/2 mΩ per square. For a 5mA load, a 10 milliinch wide printed circuit conductor 60 milliinches long will result in a voltage drop of 150µV. Use separate analog and digital ground planes with a single interconnection point to minimize ground loops. The analog pins are located adjacent to each other to help isolate analog from digital signals. Analog signals should be routed as far as possible from digital signals and should cross them at right angles. A solid analog ground plane around the D/A package, as well as under it in the vicinity of the analog and power supply pins, will isolate the D/A from switching currents. It is recommended that DCOM and ACOM be connected directly to the ground planes under the package. The analog output of DAC715 has an LSB size of 152µV (–96dB). The noise floor of the D/A must remain below this level in the frequency range of interest. The DAC715’s noise spectral density (which includes the noise contributed by the internal reference) is shown in the Typical Performance Curves section. If several DAC715s are used or if DAC715 shares supplies with other components, connecting the ACOM and DCOM lines together once at the power supplies rather than at each chip may give better results. Wiring to high-resolution D/A converters should be routed to provide optimum isolation from sources of RFI and EMI. The key to elimination of RF radiation or pickup is small loop area. Signal leads and their return conductors should be kept close together such that they present a small capture cross-section for any external field. Wire-wrap construction is not recommended. LOAD CONNECTIONS Since the reference point for VOUT and VREF OUT is the ACOM pin, it is important to connect the D/A converter load directly to the ACOM pin. Refer to Figure 5. POWER SUPPLY AND REFERENCE CONNECTIONS Lead and contact resistances are represented by R1 through R3. As long as the load resistance RL is constant, R1 simply introduces a gain error and can be removed by gain adjustment of the D/A or system-wide gain calibration. R2 is part of RL if the output voltage is sensed at ACOM. Power supply decoupling capacitors should be added as shown in Figure 4. Best performance occurs using a 1 to 10µF tantalum capacitor at –VCC. Applications with less critical settling time may be able to use 0.01µF at –VCC as In some applications it is impractical to return the load to the ACOM pin of the D/A converter. Sensing the output voltage at the SYSTEM GROUND point is reasonable, because there is no change in DAC715 ACOM current, provided that ® DAC715 8 R3 is a low-resistance ground plane or conductor. In this case you may wish to connect DCOM to SYSTEM GROUND as well. converters outputs are at approximately half scale, 0V. GAIN AND OFFSET ADJUST Connections Using Potentiometers GAIN and OFFSET adjust pins provide for trim using external potentiometers. 15-turn potentiometers provide sufficient resolution. Range of adjustment of these trims is at least ±0.3% of Full Scale Range. Refer to Figure 6. BUS INTERFACE The DAC715 has a 16-bit double-buffered data interface with control lines for easy connection to a 16-bit bus. The double-buffered feature permits update of several D/As simultaneously. DIGITAL INTERFACE A0 is the enable control for the DATA INPUT LATCH. A1 is the enable for the D/A LATCH. WR is used to strobe data into latches enabled by A0, and A1. Refer to the block diagram of Figure 1 and to Timing Diagram on page 3. Using D/A Converters The GAIN ADJUST and OFFSET ADJUST circuits of the DAC715 have been arranged so that these points may be easily driven by external D/A converters. Refer to Figure 7. 12-bit D/A converters provide an OFFSET adjust resolution and a GAIN adjust resolution of 30µV to 50µV per LSB step. CLR sets the INPUT DATA LATCH and D/A LATCH to 0000H (5V at the D/A output). SINGLE-BUFFERED OPERATION Nominal values of GAIN and OFFSET occur when the D/A DAC715 10kΩ 5kΩ VREF VOUT R1 Bus Interface RL DCOM Sense Output ACOM R2 Alternate Ground Sense Connection R3 To +VCC 0.01µF(1) 0.01µF System Ground Analog Power Supply To –VCC NOTE: (1) Locate close to DAC715 package. FIGURE 5. System Ground Considerations for High-Resolution D/A Converters. ® 9 DAC715 To operate the DAC715 interface as a single-buffered latch, the DATA INPUT LATCH is permanently enabled by connecting A0 to DCOM. If A1 is not used to enable the D/A, it should be connected to DCOM also. For this mode of operation, the width of WR will need to be at least 80ns minimum to pass data through the DATA INPUT LATCH and into the D/A LATCH. The digital interface of the DAC715 can be made transparent by asserting AO, A1, and WR LOW, and asserting CLR HIGH. TRANSPARENT INTERFACE Internal +10V Reference VREF OUT 5 P1 1kΩ 170Ω R1 100Ω Gain Adjust +VCC 6 R2 2MΩ Offset Adjust 4 15kΩ 10kΩ 5kΩ R3 27kΩ P2 10kΩ – 100kΩ –VCC ≈ +2.5V 3 IDAC 0-2mA 2 ACOM +10V VOUT For no external adjustments, pins 4 and 6 are not connected. External resistors R1 - R4 are standard ±1% values. Range of adjustment at least ±0.03% FSR. FIGURE 6. Manual Offset and Gain Adjust Circuits. ® DAC715 10 Internal +10V Reference VREF OUT R1 392Ω 170Ω Gain Adjust 10kΩ R2 33kΩ Offset Adjust 15kΩ –10 to 10V DAC 5kΩ R3 1MΩ 0 to 2mA VOUT –10 to 10V DAC R1 - R3 tolerance: ±1%, Range of adjustment at least ±0.3% FSR. DAC715 FIGURE 7. Gain and Offset Adjustment Using D/A Converters. ® 11 DAC715