Dual Low Bias Current Precision Operational Amplifier OP297 FEATURES Low Offset Voltage: 50 V Max Low Offset Voltage Drift: 0.6 V/ⴗC Max Very Low Bias Current: 100 pA Max Very High Open-Loop Gain: 2000 V/mV Min Low Supply Current (Per Amplifier): 625 A Max Operates From ⴞ2 V to ⴞ20 V Supplies High Common-Mode Rejection: 120 dB Min Pin Compatible to LT1013, AD706, AD708, OP221, LM158, and MC1458/1558 with Improved Performance 8 V+ 7 OUTB +INA 3 6 –INB V– 4 5 +INB OUTA 1 –INA 2 A B Precision performance of the OP297 includes very low offset, under 50 µV, and low drift, below 0.6 µV/°C. Open-loop gain exceeds 2000 V/mV, ensuring high linearity in every application. APPLICATIONS Strain Gage and Bridge Amplifiers High Stability Thermocouple Amplifiers Instrumentation Amplifiers Photo-Current Monitors High Gain Linearity Amplifiers Long-Term Integrators/Filters Sample-and-Hold Amplifiers Peak Detectors Logarithmic Amplifiers Battery-Powered Systems Errors due to common-mode signals are eliminated by the OP297’s common-mode rejection of over 120 dB, which minimizes offset voltage changes experienced in battery-powered systems. Supply current of the OP297 is under 625 µA per amplifier, and the part can operate with supply voltages as low as ± 2 V. GENERAL DESCRIPTION The OP297 is the first dual op amp to pack precision performance into the space-saving, industry-standard, 8-lead SOIC package. Its combination of precision with low power and extremely low input bias current makes the dual OP297 useful in a wide variety of applications. 60 PIN CONNECTIONS The OP297 uses a super-beta input stage with bias current cancellation to maintain picoamp bias currents at all temperatures. This is in contrast to FET input op amps whose bias currents start in the picoamp range at 25°C, but double for every 10°C rise in temperature, to reach the nanoamp range above 85°C. Input bias current of the OP297 is under 100 pA at 25°C and is under 450 pA over the military temperature range. Combining precision, low power, and low bias current, the OP297 is ideal for a number of applications, including instrumentation amplifiers, log amplifiers, photodiode preamplifiers, and longterm integrators. For a single device, see the OP97; for a quad, see the OP497. VS = ⴞ15V VCM = 0V 400 1200 UNITS TA = 25ⴗC VS = ⴞ15V VCM = 0V 300 20 NUMBER OF UNITS INPUT CURRENT (pA) 40 IB– 0 IB+ –20 IOS 100 –40 –60 –75 200 –50 –25 0 25 50 TEMPERATURE (ⴗC) 75 100 125 0 –100 –80 –60 –40 –20 0 20 40 60 INPUT OFFSET VOLTAGE (V) 80 100 Figure 1. Low Bias Current over Temperature Figure 2. Very Low Offset REV. E 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. 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 companies. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 www.analog.com Fax: 781/326-8703 © 2003 Analog Devices, Inc. All rights reserved. OP297–SPECIFICATIONS ELECTRICAL CHARACTERISTICS (@ VS = ⴞ15 V, TA = 25ⴗC, unless otherwise noted.) Parameter Symbol Conditions Input Offset Voltage Long-Term Input Voltage Stability Input Offset Current Input Bias Current Input Noise Voltage Input Noise Voltage Density VOS IOS IB en p-p en Input Noise Current Density Input Resistance Differential Mode Input Resistance Common-Mode Large-Signal Voltage Gain Input Voltage Range* Common-Mode Rejection Power Supply Rejection Output Voltage Swing in AVO VCM CMRR PSRR VO Supply Current per Amplifier Supply Voltage Slew Rate Gain Bandwidth Product Channel Separation ISY VS SR GBWP CS Input Capacitance CIN OP297E OP297F OP297G Typ Max Min Typ Max Min Typ Max Min 25 0.1 20 20 0.5 20 17 20 VCM = 0 V VCM = 0 V 0.1 Hz to 10 Hz fO = 10 Hz fO = 1000 Hz fO = 10 Hz RIN RINCM VO = ± 10 V RL = 2 kΩ 2000 ± 13 120 VCM = ± 13 V VS = ± 2 V to ± 20 V 120 RL = 10 kΩ ± 13 ± 13 RL = 2 kΩ No Load Operating Range ±2 0.05 AV = +1 VO = 20 V p-p fO = 10 Hz 50 50 0.1 35 35 0.5 20 17 20 100 ± 100 100 150 ± 150 Unit µV 80 200 0.1 50 50 0.5 20 17 20 µV/mo 200 pA ± 200 pA µV p-p nV/√Hz nV/√Hz fA/√Hz 30 30 30 MΩ 500 500 500 GΩ 3200 ± 14 135 125 ± 14 ± 13.7 525 625 ± 20 0.15 500 150 V/mV V dB dB V V µA V V/µs kHz dB 3 pF 4000 ± 14 140 130 ± 14 ± 13.7 525 1500 ± 13 114 114 ± 13 ± 13 625 ± 20 0.15 500 150 ±2 0.05 3 3200 ± 14 135 125 ± 14 ± 13.7 525 625 ± 20 0.15 500 150 1200 ± 13 114 114 ± 13 ± 13 ±2 0.05 3 *Guaranteed by CMR test. Specifications subject to change without notice. ELECTRICAL CHARACTERISTICS (@ VS = ⴞ15 V, –40ⴗC ⱕ TA ⱕ +85ⴗC for OP297E/F/G, unless otherwise noted.) Parameter Symbol Conditions Input Offset Voltage Average Input Offset Voltage Drift Input Offset Current Input Bias Current Large-Signal Voltage Gain VOS TCVOS IOS IB AVO Input Voltage Range* Common-Mode Rejection Power Supply Rejection VCM CMRR PSRR Output Voltage Swing Supply Current per Amplifier Supply Voltage VO ISY VS VCM = 0 V VCM = 0 V VO = ± 10 V, RL = 2 kΩ VCM = ± 13 VS = ± 2.5 V to ± 20 V RL = 10 kΩ No Load Operating Range Min OP297E Typ Max Min OP297F OP297G Typ Max Min Typ Max Unit µV 35 100 80 300 110 400 0.2 50 50 0.6 450 ± 450 0.5 80 80 2.0 750 ± 750 0.6 80 80 2.0 µV/°C 750 pA ± 750 pA 1200 3200 ± 13 ± 13.5 114 130 1000 2500 ± 13 ± 13.5 108 130 800 ± 13 108 114 ± 13 108 ± 13 108 ± 13 0.15 ± 13.4 550 ± 2.5 750 ± 20 ± 2.5 0.15 ± 13.4 550 750 ± 20 2500 ± 13.5 130 0.3 ± 13.4 550 750 ± 2.5 ± 20 V/mV V dB dB V µA V *Guaranteed by CMR test. Specifications subject to change without notice. –2– REV. E OP297 ABSOLUTE MAXIMUM RATINGS 1 Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 20 V Input Voltage2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 20 V Differential Input Voltage2 . . . . . . . . . . . . . . . . . . . . . . . . 40 V Output Short-Circuit Duration . . . . . . . . . . . . . . . . . Indefinite Storage Temperature Range Z Package . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +175°C P, S Packages . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C Operating Temperature Range OP297E (Z) . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C OP297F, OP297G (P, S) . . . . . . . . . . . . . . –40°C to +85°C Junction Temperature Z Package . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +175°C P, S Packages . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C Lead Temperature Range (Soldering, 60 sec) . . . . . . . . 300°C Package Types JA3 JC Unit 8-Lead CERDIP (Z) 8-Lead PDIP (P) 8-Lead SOIC (S) 134 96 150 12 37 41 °C/W °C/W °C/W NOTES 1 Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; and 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. 2 For supply voltages less than ± 20 V, the absolute maximum input voltage is equal to the supply voltage. 3 JA is specified for worst case mounting conditions, i.e., JA is specified for device in socket for CERDIP and PDIP, packages; JA is specified for device soldered to printed circuit board for SOIC package. ORDERING GUIDE Model Temperature Range Package Description Package Options OP297EZ OP297FP OP297FS OP297FS-REEL OP297FS-REEL7 OP297GP OP297GS OP297GS-REEL OP297GS-REEL7 –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C –40°C to +85°C 8-Lead CERDIP 8-Lead PDIP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC 8-Lead PDIP 8-Lead SOIC 8-Lead SOIC 8-Lead SOIC Q-8 N-8 R-8 R-8 R-8 N-8 R-8 R-8 R-8 CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the OP297 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. 1/2 OP297 V1 20Vp-p @ 10Hz 2k⍀ 50k⍀ 50⍀ 1/2 OP297 V2 CHANNEL SEPARATION = 20 log ) V1 V2 /10000 ) Figure 3. Channel Separation Test Circuit REV. E –3– OP297–Typical Performance Characteristics TA = 25ⴗC VS = ⴞ15V VCM = 0V 1200 UNITS TA = 25ⴗC VS = ⴞ15V VCM = 0V 1200 UNITS 200 TA = 25ⴗC VS = ⴞ15V VCM = 0V 1200 UNITS 200 NUMBER OF UNITS 300 300 NUMBER OF UNITS NUMBER OF UNITS 400 250 400 150 100 200 100 100 50 0 –100 –80 –60 –40 –20 0 20 40 60 80 100 INPUT OFFSET VOLTAGE (pA) 0 –100 –80 –60 –40 –20 0 20 40 60 80 100 INPUT BIAS CURRENT (pA) TPC 2. Typical Distribution of Input Bias Current 60 60 VS = ⴞ15V VCM = 0V ⴞ3 VS = ⴞ15V VCM = 0V IB– 20 INPUT CURRENT (pA) INPUT CURRENT (pA) 40 IB– 0 IB + –20 IOS –50 –25 0 25 50 75 TEMPERATURE (ⴗC) EFFECTIVE OFFSET VOLTAGE DRIFT (V/ⴗC) EFFECTIVE OFFSET VOLTAGE (V) BALANCED OR UNBALANCED VS = ⴞ15V VCM = 0V 1000 100 +125ⴗC TA = +25ⴗC 10 10 100 1k 10k 100k 1M SOURCE RESISTANCE (⍀) –10 –5 0 5 10 COMMON-MODE VOLTAGE (V) TA = 25ⴗC VS = ⴞ15V VCM = 0V ⴞ2 ⴞ1 0 15 TPC 5. Input Bias, Offset Current vs. Common-Mode Voltage 10000 TA IOS –40 –15 100 125 TPC 4. Input Bias, Offset Current vs. Temperature –55ⴗC 0 –20 –40 –60 –75 IB + 20 10M TPC 7. Effective Offset Voltage vs. Source Resistance 100 10 1 1k 10k 100k 1M 10M SOURCE RESISTANCE (⍀) TPC 8. Effective TCVOS vs. Source Resistance –4– 1 2 3 4 5 TIME AFTER POWER APPLIED (Minutes) 35 BALANCED OR UNBALANCED VS = ⴞ15V VCM = 0V 0.1 100 0 TPC 6. Input Offset Voltage Warm-Up Drift SHORT-CIRCUIT CURRENT (mA) 40 TPC 3. Typical Distribution of Input Offset Current DEVIATION FROM FINAL VALUE (V) TPC 1. Typical Distribution of Input Offset Voltage 0 –100 –80 –60 –40 –20 0 20 40 60 80 100 INPUT OFFSET VOLTAGE (pA) 100M TA = –55ⴗC 30 25 20 15 10 5 TA = +25ⴗC TA = +125ⴗC VS = ⴞ15V OUTPUT SHORTED TO GROUND 0 –5 –10 –15 –20 –25 –30 –35 TA = +125ⴗC TA = +25ⴗC TA = –55ⴗC 0 1 2 3 4 TIME FROM OUTPUT SHORT (Minutes) TPC 9. Short Circuit Current vs. Time, Temperature REV. E OP297 160 160 COMMON-MODE REJECTION (dB) 1200 1100 TA = +25ⴗC 1000 TA = –55ⴗC 900 800 ⴞ5 ⴞ10 ⴞ15 SUPPLY VOLTAGE (V) 0 TPC 10. Total Supply Current vs. Supply Voltage 100 CURRENT NOISE VOLTAGE NOISE 10 100 80 60 1 100 1k 10k FREQUENCY (Hz) 10 100k 10 TA = 25ⴗC VS = ⴞ15V ⌬VS = 10Vp-p 140 120 100 80 60 40 0.1 1M 10 1000 TA = 25ⴗC VS = ⴞ2V TO ⴞ15V 100 120 TPC 11. Common-Mode Rejection Frequency CURRENT NOISE DENSITY (fA/ Hz) VOLTAGE NOISE DENSITY (nV/ Hz) 1000 140 40 ⴞ20 TA = 25ⴗC VS = ⴞ15V 1 10 100 FREQUENCY (Hz) 1 1000 TA = +25ⴗC 1 10Hz 1kHz 0.1 0.01 102 1000 107 1 TA = +25ⴗC 0 TA = –55ⴗC 25 –5 0 5 10 OUTPUT VOLTAGE (V) TPC 16. Differential Input Voltage vs. Output Voltage REV. E 15 TA = 25ⴗC VS = ⴞ15V AVCL = +1 1%THD fO = 1kHz RL = 10k⍀ 30 20 15 10 25 20 15 10 5 0 –10 20 35 TA = 25ⴗC VS = ⴞ15V AVCL = +1 1%THD fO = 1kHz 5 –15 3 4 5 10 2 LOAD RESISTANCE (k⍀) TPC 15. Open-Loop Gain vs. Load Resistance OUTPUT SWING (Vp-p) OUTPUT SWING (Vp-p) DIFFERENTIAL INPUT VOLTAGE (10V/DIV) 100 103 104 105 106 SOURCE RESISTANCE (⍀) TPC 14. Total Noise Density vs. Source Resistance 30 TA = +125ⴗC TA = –55ⴗC VS = ⴞ15V VO = ⴞ10V 35 RL = 10k⍀ VS = ⴞ15V VCM = 0V 100k 1M TA = +125ⴗC 1kHz TPC 13. Voltage Noise Density and Current Noise Density vs. Frequency 10 100 1k 10k FREQUENCY (Hz) 10000 TA = 25ⴗC VS = ⴞ2V TO ⴞ20V 10Hz 1 1 TPC 12. Power Supply Rejection vs. Frequency OPEN-LOOP GAIN (V/mV) TA = +125ⴗC TOTAL NOISE DENSITY (nV/ Hz) TOTAL SUPPLY CURRENT (A) NO LOAD POWER SUPPLY REJECTION (dB) 1300 10 100 1k LOAD RESISTANCE (⍀) 10k TPC 17. Output Swing vs. Load Resistance –5– 0 100 1k 10k FREQUENCY (Hz) TPC 18. Maximum Output Swing vs. Frequency 100k OP297 70 VS = ⴞ15V CL = 30pF RL = 1M⍀ 40 PHASE TA = –55ⴗC 20 0 OVERSHOOT (%) OPEN-LOOP GAIN (dB) GAIN 60 60 PHASE SHIFT (Deg) 80 1000 TA = 25ⴗC VS = ⴞ15V AVCL = +1 VOUT = 100mV p-p –20 50 TA = 25ⴗC VS = ⴞ15V 100 –EDGE OUTPUT IMPEDANCE (⍀) 100 40 +EDGE 30 20 10 1 0.1 0.01 10 TA = +125ⴗC –40 100 0.001 10 0 1k 100 10k FREQUENCY (Hz) 1M 10M 0 TPC 19. Open Loop Gain, Phase vs. Frequency 100 1000 LOAD CAPACITANCE (pF) 10000 TPC 20. Small-Signal Overshoot vs. Load Capacitance 100 1k 10k 100k FREQUENCY (Hz) 1M TPC 21. Open Loop Output Impedance vs Frequency APPLICATIONS INFORMATION Extremely low bias current over a wide temperature range makes the OP297 attractive for use in sample-and-hold amplifiers, peak detectors, and log amplifiers that must operate over a wide temperature range. Balancing input resistances is unnecessary with the OP297. Offset voltage and TCVOS are degraded only minimally by high source resistance, even when unbalanced. 100 90 The input pins of the OP297 are protected against large differential voltage by back-to-back diodes and current-limiting resistors. Common-mode voltages at the inputs are not restricted and may vary over the full range of the supply voltages used. 10 0% 20mV The OP297 requires very little operating headroom about the supply rails and is specified for operation with supplies as low as 2 V. Typically, the common-mode range extends to within 1 V of either rail. The output typically swings to within 1 V of the rails when using a 10 kΩ load. 5s Figure 5. Small-Signal Transient Response (CLOAD = 1000 pF, AVCL = 1) AC PERFORMANCE The OP297’s ac characteristics are highly stable over its full operating temperature range. Unity gain small-signal response is shown in Figure 4. Extremely tolerant of capacitive loading on the output, the OP297 displays excellent response with 1000 pF loads (Figure 5). 100 90 10 0% 20mV 100 5s 90 Figure 6. Large-Signal Transient Response (AVCL = 1) 10 0% 20mV 5s Figure 4. Small-Signal Transient Response (CLOAD = 100 pF, AVCL = 1) –6– REV. E OP297 UNITY-GAIN FOLLOWER APPLICATIONS PRECISION ABSOLUTE VALUE AMPLIFIER NONINVERTING AMPLIFIER 1/2 OP297 The circuit of Figure 9 is a precision absolute value amplifier with an input impedance of 30 MΩ. The high gain and low TCVOS of the OP297 ensure accurate operation with microvolt input signals. In this circuit, the input always appears as a commonmode signal to the op amps. The CMR of the OP297 exceeds 120 dB, yielding an error of less than 2 ppm. 1/2 OP297 +15V C2 0.1F MINI-DIP BOTTOM VIEW INVERTING AMPLIFIER 8 R1 1k⍀ 1 C1 30pF A 2 1/2 OP297 R3 1k⍀ B VIN 3 1/2 OP297 4 5 D1 1N4148 8 1 6 D2 1N4148 C3 0.1F 1/2 OP297 7 0V VOUT 10V R2 2k⍀ –15V Figure 7. Guard Ring Layout and Connections Figure 9. Precision Absolute Value Amplifier GUARDING AND SHIELDING To maintain the extremely high input impedances of the OP297, care must be taken in circuit board layout and manufacturing. Board surfaces must be kept scrupulously clean and free of moisture. Conformal coating is recommended to provide a humidity barrier. Even a clean PC board can have 100 pA of leakage currents between adjacent traces, so guard rings should be used around the inputs. Guard traces are operated at a voltage close to that on the inputs, as shown in Figure 7, so that leakage currents become minimal. In noninverting applications, the guard ring should be connected to the common-mode voltage at the inverting input. In inverting applications, both inputs remain at ground, so the guard trace should be grounded. Guard traces should be on both sides of the circuit board. PRECISION CURRENT PUMP Maximum output current of the precision current pump shown in Figure 10 is ±10 mA. Voltage compliance is ±10 V with ±15 V supplies. Output impedance of the current transmitter exceeds 3 MΩ with linearity better than 16 bits. R3 10k⍀ R1 10k⍀ VIN R2 10k⍀ 2 3 1/2 OP297 R6 10k⍀ 1 +15V R4 10k⍀ OPEN-LOOP GAIN LINEARITY The OP297 has both an extremely high gain of 2000 V/mV minimum and constant gain linearity. This enhances the precision of the OP297 and provides for very high accuracy in high closed loop gain applications. Figure 8 illustrates the typical open-loop gain linearity of the OP297 over the military temperature range. IOUT = VIN R5 = VIN 100⍀ 8 7 1/2 OP297 5 6 = 10mA/V –15V DIFFERENTIAL INPUT VOLTAGE (10V/DIV) Figure 10. Precision Current Pump RL = 10k⍀ VS = ⴞ15V VCM = 0V TA = +125ⴗC TA = +25ⴗC 0 TA = –55ⴗC –15 –10 –5 0 5 10 OUTPUT VOLTAGE (V) 15 Figure 8. Open-Loop Linearity of the OP297 REV. E –7– IOUT 10mA OP297 All the transistors of the MAT04 are precisely matched and at the same temperature, so the IS and VT terms cancel, giving PRECISION POSITIVE PEAK DETECTOR In Figure 11, the CH must be of polystyrene, Teflon®, or polyethylene to minimize dielectric absorption and leakage. The droop rate is determined by the size of CH and the bias current of the OP297. 2 ln IIN = ln IO + ln IREF = ln(IO × IREF ) Exponentiating both sides of the equation leads to 1k⍀ IO = +15V 1N4148 2 VIN 1k⍀ 3 6 1 1k⍀ 5 1/2 OP297 1k⍀ 7 VOUT Op amp A2 forms a current-to-voltage converter, which gives VOUT = R2 × IO. Substituting (VIN/R1) for IIN and the above equation for IO yields 2 R 2 VIN VOUT = IREF R1 0.1F CH RESET IREF 0.1F 8 1/2 OP297 (IIN )2 2N930 –15V A similar analysis made for the square-root circuit of Figure 14 leads to its transfer function Figure 11. Precision Positive Peak Detector VOUT = R 2 SIMPLE BRIDGE CONDITIONING AMPLIFIER (VIN )(IREF ) R1 Figure 12 shows a simple bridge conditioning amplifier using the OP297. The transfer function is C2 100pF ∆R RF VOUT = VREF R + ∆R R R2 33k⍀ 6 The REF43 provides an accurate and stable reference voltage for the bridge. To maintain the highest circuit accuracy, RF should be 0.1% or better with a low temperature coefficient. 2 IO 1 Q1 3 7 Q2 5 6 15V 8 C1 100pF V+ REF43 2 4 R + ⌬R 3 1/2 OP297 1/2 OP297 1 VIN VOUT R1 33k⍀ 3 Q3 10 1/2 OP297 IREF 9 8 2 5 8 1/2 OP297 7 VOUT = VREF RF R + ⌬R R 14 13 Q4 R3 50k⍀ 1 R4 50k⍀ –15V V– ⌬R VOUT 12 4 6 7 MAT04E RF VREF 5 Figure 13. Squaring Amplifier 4 R2 33k⍀ Figure 12. A Simple Bridge Conditioning Amplifier Using the OP297 C2 100pF 6 NONLINEAR CIRCUITS Due to its low input bias currents, the OP297 is an ideal log amplifier in nonlinear circuits such as the square and squareroot circuits shown in Figures 13 and 14. Using the squaring circuit of Figure 13 as an example, the analysis begins by writing a voltage loop equation across transistors Q1, Q2, Q3, and Q4. IO Q1 VIN 2 3 8 1/2 OP297 1 Q2 5 7 13 8 Q3 10 14 Q4 12 9 R3 50k⍀ R4 50k⍀ 4 V– VOUT IREF MAT04E 1 7 6 V+ R1 33k⍀ 1/2 OP297 3 C1 100pF I I I I VT1 ln IN + VT 2 ln IN = VT 3 ln O + VT 4 ln REF I S1 IS 2 IS 3 IS 4 5 –15V Figure 14. Square-Root Amplifier –8– REV. E OP297 In these circuits, IREF is a function of the negative power supply. To maintain accuracy, the negative supply should be well regulated. For applications where very high accuracy is required, a voltage reference may be used to set IREF. An important consideration for the squaring circuit is that a sufficiently large input voltage can force the output beyond the operating range of the output op amp. Resistor R4 can be changed to scale IREF, or R1, and R2 can be varied to keep the output voltage within the usable range. OP297 SPICE MACRO MODEL Figures 14 and 15 show the node end net list for a SPICE macro model of the OP297. The model is a simplified version of the actual device and simulates important dc parameters such as VOS, IOS, IB, AVO, CMR, VO, and ISY. AC parameters such as slew rate, gain and phase response, and CMR change with frequency are also simulated by the model. The model uses typical parameters for the OP297. The poles and zeros in the model were determined from the actual openand closed-loop gain and phase response of the OP297. In this way, the model presents an accurate ac representation of the actual device. The model assumes an ambient temperature of 25°C. Unadjusted accuracy of the square-root circuit is better than 0.1% over an input voltage range of 100 mV to 10 V. For a similar input voltage range, the accuracy of the squaring circuit is better than 0.5%. 99 V2 R3 R4 13 C2 5 6 12 15 –IN 2 RIN2 8 Q1 R1 CIN +IN IOS 1 RIN1 3 R2 7 D1 D2 G1 Q2 10 11 R5 4 R6 C3 R7 D4 14 I1 R10 C5 V3 C6 C7 R11 R13 E2 R12 E3 R14 G3 R15 C8 98 9 99 D7 R16 ISYS G6 D8 D5 26 V4 D6 27 V5 22 23 25 L1 G7 D9 G4 G5 D10 50 Figure 15. Macro Model REV. E R18 28 29 R17 –9– 16 R9 98 50 G1 R8 E1 9 EOS C4 D3 R19 EREF OP297 SPICE Net List *OP297 SPICE MACRO-MODEL * *NODE ASSIGNMENTS NONINVERTING INPUT INVERTING INPUT OUTPUT POSITIVE SUPPLY NEGATIVE SUPPLY *SUBCKT OP297 1 2 30 99 50 * *INPUT STAGE & POLE AT 6 MHz * RIN1 1 7 2500 RIN2 2 8 2500 R1 8 3 5E11 R2 7 3 5E11 R3 5 99 612 R4 6 99 612 CIN 7 8 3E-12 C2 5 6 21.67E-12 I1 4 50 0.1E-3 IOS 7 8 20E-12 EOS 9 7 POLY(1) 19 23 25E-6 1 Q1 5 8 10 QX Q2 6 9 11 QX R5 10 4 96 R6 11 4 96 D1 8 9 DX D2 9 8 DX * EREF 98 0 23 0 1 * *GAIN STAGE & DOMINANT POLE AT 0.13 HZ * R7 12 98 2.45E9 C3 12 98 500E-12 G1 98 12 56 1.634E-3 V2 99 13 1.5 V3 14 50 1.5 D3 12 13 DX D4 14 12 DX * *NEGATIVE ZERO AT -1.8 MHz * R8 15 16 1E6 C4 15 16 –88.4E-15 R9 16 98 1 E1 15 98 12 23 1E6 * *POLE AT 1.8 MHz * R10 17 98 1E6 C5 17 98 88 4E-15 G2 98 17 16 23 1 E-6 * *COMMON-MODE GAIN NETWORK WITH ZERO AT 50 HZ * R11 18 19 1E6 C6 18 19 3.183E-9 R12 19 98 1 E2 18 98 3 23 100E-3 * *POLE AT 6 MHz * R15 22 98 1E6 C8 22 98 26.53E-15 G3 98 22 17 23 1 E-6 * *OUTPUT STAGE * R16 23 99 160E3 R17 23 50 160E3 ISY 99 50 331E-6 R18 25 99 200 R19 25 50 200 L1 25 30 1E-7 G4 28 50 22 25 5E-3 G5 29 50 25 22 5E-3 G6 25 99 99 22 5E-3 G7 50 25 22 50 5E-3 V4 26 25 1.8 V5 25 27 1.3 D5 22 26 DX D6 27 22 DX D7 99 28 DX D8 99 29 DX D9 50 28 DY D10 50 29 DY * *MODELS USED * .MODEL QX NPN BF=2.5E6) .MODEL DX D IS = 1E-15) .MODEL DY D IS = 1E-15 BV = 50) .ENDS OP297 –10– REV. E OP297 OUTLINE DIMENSIONS 8-Lead Plastic Dual In-Line Package [PDIP] P-Suffix (N-8) 8-Lead Ceramic Dual In-Line Package [CERDIP] Z-Suffix (Q-8) Dimensions shown in inches and (millimeters) Dimensions shown in inches and (millimeters) 0.005 (0.13) MIN 0.375 (9.53) 0.365 (9.27) 0.355 (9.02) 0.055 (1.40) MAX 8 8 1 5 4 0.295 (7.49) 0.285 (7.24) 0.275 (6.98) 0.180 (4.57) MAX 0.150 (3.81) 0.130 (3.30) 0.110 (2.79) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) 0.310 (7.87) 0.220 (5.59) PIN 1 1 0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.100 (2.54) BSC 5 0.015 (0.38) MIN 0.100 (2.54) BSC 0.150 (3.81) 0.135 (3.43) 0.120 (3.05) 0.060 (1.52) 0.015 (0.38) 0.200 (5.08) MAX 0.150 (3.81) MIN 0.200 (5.08) 0.125 (3.18) 0.023 (0.58) 0.014 (0.36) SEATING 0.070 (1.78) PLANE 0.030 (0.76) 8-Lead Standard Small Outline Package (SOIC) Narrow Body S-Suffix (R-8) Dimensions shown in millimeters and (inches) 5.00 (0.1968) 4.80 (0.1890) 8 5 1 4 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0040) COPLANARITY SEATING 0.10 PLANE 6.20 (0.2440) 5.80 (0.2284) 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.31 (0.0122) 0.50 (0.0196) ⴛ 45ⴗ 0.25 (0.0099) 8ⴗ 0.25 (0.0098) 0ⴗ 1.27 (0.0500) 0.40 (0.0157) 0.17 (0.0067) COMPLIANT TO JEDEC STANDARDS MS-012AA CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN REV. E 15 0 0.015 (0.38) 0.008 (0.20) CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETERS DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN COMPLIANT TO JEDEC STANDARDS MO-095AA CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS (IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN 4.00 (0.1574) 3.80 (0.1497) 0.320 (8.13) 0.290 (7.37) 0.405 (10.29) MAX 0.015 (0.38) 0.010 (0.25) 0.008 (0.20) SEATING PLANE 0.060 (1.52) 0.050 (1.27) 0.045 (1.14) 4 –11– OP297 Revision History Location Page 7/03—Data Sheet changed from REV. D to REV. E. Edits to Figures 12 and 14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Changes to NONLINEAR CIRCUITS Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 10/02—Data Sheet changed from REV. C to REV. D. Edits to Figure 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 10/02—Data Sheet changed from REV. B to REV. C. Edits to SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Deleted WAFER TEST LIMITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Deleted DICE CHARACTERISTICS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Deleted ABSOLUTE MAXIMUM RATINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Edits to ORDERING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Updated OUTLINE DIMENSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 –12– REV. E C00300–0–7/03(E) Changes to TPCS 13 and 16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4