a Micropower, Rail-to-Rail Input and Output Operational Amplifiers OP196/OP296/OP496 FEATURES Rail-to-Rail Input and Output Swing Low Power: 60 mA/Amplifier Gain Bandwidth Product: 450 kHz Single-Supply Operation: +3 V to +12 V Low Offset Voltage: 300 mV max High Open-Loop Gain: 500 V/mV Unity-Gain Stable No Phase Reversal APPLICATIONS Battery Monitoring Sensor Conditioners Portable Power Supply Control Portable Instrumentation PIN CONFIGURATIONS 8-Lead Narrow-Body SO NULL 1 –IN A 2 +IN A 3 8 NC OP196 V– 4 7 V+ 6 OUT A 5 NULL NC = NO CONNECT NULL 1 –IN A 8 NC OP196 7 V+ 2 6 OUT A +IN A 3 V– 5 NULL 4 NC = NO CONNECT 8-Lead Narrow-Body SO OUT A 1 OP296 +IN A 3 GENERAL DESCRIPTION 8-Lead Plastic DIP 8 V+ –IN A 2 V– 4 7 OUT B OUT A 1 OP296 V+ 8 6 –IN B –IN A 2 7 OUT B 5 +IN B +IN A 3 6 –IN B V– 4 5 +IN B The OP196 family of CBCMOS operational amplifiers features micropower operation and rail-to-rail input and output ranges. The extremely low power requirements and guaranteed operation from +3 V to +12 V make these amplifiers perfectly suited to monitor battery usage and to control battery charging. Their dynamic performance, including 26 nV/√Hz voltage noise density, recommends them for battery-powered audio applications. Capacitive loads to 200 pF are handled without oscillation. 8-Lead Plastic DIP 8-Lead TSSOP 1 OUT A –IN A +IN A V– 8 V+ OUT B –IN B +IN B OP296 4 5 The OP196/OP296/OP496 are specified over the HOT extended industrial (–40°C to +125°C) temperature range. +3 V operation is specified over the 0°C to +125°C temperature range. The single OP196 and the dual OP296 are available in 8-lead plastic DIP and SO-8 surface mount packages. The quad OP496 is available in 14-lead plastic DIP and narrow SO-14 surface mount packages. 14-Lead Narrow-Body SO 14-Lead Plastic DIP OUT A 1 14 OUT D –IN A 2 13 –IN D +IN A 3 12 +IN D –IN A 11 V– +IN A 3 +V 4 OP496 +IN B 5 10 +IN C –IN B 6 9 –IN C OUT B 7 8 OUT C OUT A 1 14 OUT D 2 +V 4 +IN B 5 13 –IN D 12 +IN D OP496 11 V– 10 +IN C 6 9 –IN C OUT B 7 8 OUT C –IN B 14-Lead TSSOP (RU Suffix) 1 OUT A –IN A +IN A V+ +IN B –IN B OUT B REV. B 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 which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 14 OUT D –IN D +IN D V– +IN C –IN C OUT C OP496 7 8 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 1998 OP196/OP296/OP496–SPECIFICATIONS ELECTRICAL SPECIFICATIONS (@ V = +5.0 V, V S CM = +2.5 V, TA = +258C unless otherwise noted) Parameter Symbol Conditions INPUT CHARACTERISTICS Offset Voltage VOS OP196G, OP296G, OP496G –40°C ≤ TA ≤ +125°C OP296H, OP496H –40°C ≤ TA ≤ +125°C –40°C ≤ TA ≤ +125°C Input Bias Current Input Offset Current IB IOS Input Voltage Range VCM Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain AVO Long-Term Offset Voltage VOS Offset Voltage Drift ∆VOS/∆T OUTPUT CHARACTERISTICS Output Voltage Swing High VOH Output Voltage Swing Low VOL Output Current IOUT POWER SUPPLY Power Supply Rejection Ratio Supply Current per Amplifier PSRR ISY Min IL = –100 µA IL = 1 mA IL = 2 mA IL = –1 mA IL = –1 mA IL = –2 mA ± 2.5 V ≤ VS ≤ ±6 V, –40°C ≤ TA ≤ +125°C VOUT = 2.5 V, R L = ∞ –40°C ≤ TA ≤ +125°C Max Units 35 300 650 800 1.2 ± 50 ±8 ± 20 µV µV µV mV nA nA nA +5.0 V ± 10 ± 1.5 –40°C ≤ TA ≤ +125°C 0 V ≤ VCM ≤ 5.0 V, –40°C ≤ TA ≤ +125°C RL = 100 kΩ, 0.30 V ≤ VOUT ≤ 4.7 V, –40°C ≤ TA ≤ +125°C G Grade, Note 1 H Grade, Note 1 G Grade, Note 2 H Grade, Note 2 Typ 0 65 150 dB 200 1.5 2 V/mV µV mV µV/°C µV/°C 4.92 4.56 4.1 36 350 750 ±4 V V V mV mV mV mA 550 1 4.85 4.30 70 550 85 45 60 80 dB µA µA DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin SR GBP øm RL = 100 kΩ 0.3 350 47 V/µs kHz Degrees NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density en p-p en in 0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz 0.8 26 0.19 µV p-p nV/√Hz pA/√Hz NOTES 1 Long-term offset voltage is guaranteed by a 1000 hour life test performed on three independent lots at +125 °C, with an LTPD of 1.3. 2 Offset voltage drift is the average of the –40°C to +25°C delta and the +25°C to +125°C delta. Specifications subject to change without notice. –2– REV. B OP196/OP296/OP496 ELECTRICAL SPECIFICATIONS (@ V S = +3.0 V, VCM = +1.5 V, TA = +258C unless otherwise noted) Parameter Symbol Conditions INPUT CHARACTERISTICS Offset Voltage VOS OP196G, OP296G, OP496G 0°C ≤ TA ≤ +125°C OP296H, OP496H 0°C ≤ TA ≤ +125°C Input Bias Current Input Offset Current IB IOS Input Voltage Range VCM Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain Long-Term Offset Voltage AVO VOS Offset Voltage Drift ∆VOS/∆T 0 V ≤ VCM ≤ 3.0 V, 0°C ≤ TA ≤ +125°C RL = 100 kΩ G Grade, Note 1 H Grade, Note 1 G Grade, Note 2 H Grade, Note 2 Min Typ Max Units 35 300 650 800 1.2 ± 50 ±8 µV µV µV mV nA nA +3.0 V 550 1 dB V/mV µV mV µV/°C µV/°C ± 10 ±1 0 60 80 200 1.5 2 OUTPUT CHARACTERISTICS Output Voltage Swing High Output Voltage Swing Low VOH VOL IL = 100 µA IL = –100 µA POWER SUPPLY Supply Current per Amplifier ISY VOUT = 1.5 V, R L = ∞ 0°C ≤ TA ≤ +125°C DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin SR GBP øm RL = 100 kΩ 0.25 350 45 V/µs kHz Degrees NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density en p-p en in 0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz 0.8 26 0.19 µV p-p nV/√Hz pA/√Hz 2.85 40 NOTES 1 Long-term offset voltage is guaranteed by a 1000 hour life test performed on three independent lots at +125 °C, with an LTPD of 1.3. 2 Offset voltage drift is the average of the 0°C to +25°C delta and the +25°C to +125°C delta. Specifications subject to change without notice. REV. B –3– 70 V mV 60 80 µA µA OP196/OP296/OP496 ELECTRICAL SPECIFICATIONS (@ V = +12.0 V, V S CM = +6 V, TA = +258C unless otherwise noted) Parameter Symbol Conditions INPUT CHARACTERISTICS Offset Voltage VOS OP196G, OP296G, OP496G 0°C ≤ TA ≤ +125°C OP296H, OP496H 0°C ≤ TA ≤ +125°C –40°C ≤ TA ≤ +125°C Input Bias Current Input Offset Current IB IOS Input Voltage Range VCM Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain Long-Term Offset Voltage AVO VOS Offset Voltage Drift ∆VOS/∆T OUTPUT CHARACTERISTICS Output Voltage Swing High VOH Output Voltage Swing Low VOL Output Current IOUT POWER SUPPLY Supply Current per Amplifier Supply Voltage Range ISY Min IL = 100 µA IL = 1 mA IL = –1 mA IL = –1 mA Max Units 35 300 650 800 1.2 ± 50 ±8 ± 15 µV µV µV mV nA nA nA +12 V 550 1 1.5 2 dB V/mV µV mV µV/°C µV/°C ±4 V V mV mV mA ± 10 ±1 –40°C ≤ TA ≤ +125°C 0 V ≤ VCM ≤ +12 V, –40°C ≤ TA ≤ +125°C RL = 100 kΩ G Grade, Note 1 H Grade, Note 1 G Grade, Note 2 H Grade, Note 2 Typ 0 65 300 1000 11.85 11.30 VOUT = 6 V, RL = ∞ –40°C ≤ TA ≤ +125°C VS 70 550 60 80 +12 +3 µA µA V DYNAMIC PERFORMANCE Slew Rate Gain Bandwidth Product Phase Margin SR GBP øm RL = 100 kΩ 0.3 450 50 V/µs kHz Degrees NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density en p-p en in 0.1 Hz to 10 Hz f = 1 kHz f = 1 kHz 0.8 26 0.19 µV p-p nV/√Hz pA/√Hz NOTES 1 Long-term offset voltage is guaranteed by a 1000 hour life test performed on three independent lots at +125 °C, with an LTPD of 1.3. 2 Offset voltage drift is the average of the –40°C to +25°C delta and the +25°C to +125°C delta. Specifications subject to change without notice. –4– REV. B OP196/OP296/OP496 ABSOLUTE MAXIMUM RATINGS 1 ORDERING GUIDE Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+15 V Input Voltage2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +15 V Differential Input Voltage2 . . . . . . . . . . . . . . . . . . . . . . . +15 V Output Short Circuit Duration . . . . . . . . . . . . . . . . . Indefinite Storage Temperature Range P, S, RU Package . . . . . . . . . . . . . . . . . . . . –65°C to +150°C Operating Temperature Range OP196G, OP296G, OP496G, H . . . . . . . – 40°C to +125°C Junction Temperature Range P, S, RU Package . . . . . . . . . . . . . . . . . . . – 65°C to +150°C Lead Temperature Range (Soldering, 60 sec) . . . . . . . +300°C Package Type uJA3 uJC Units 8-Lead Plastic DIP 8-Lead SOIC 8-Lead TSSOP 14-Lead Plastic DIP 14-Lead SOIC 14-Lead TSSOP 103 158 240 83 120 180 43 43 43 39 36 35 °C/W °C/W °C/W °C/W °C/W °C/W Model Temperature Range Package Description Package Option OP196GP OP196GS –40°C to +125°C –40°C to +125°C 8-Lead Plastic DIP 8-Lead SOIC N-8 SO-8 OP296GP –40°C to +125°C OP296GS –40°C to +125°C OP296HRU –40°C to +125°C 8-Lead Plastic DIP 8-Lead SOIC 8-Lead TSSOP N-8 SO-8 RU-8 OP496GP –40°C to +125°C OP496GS –40°C to +125°C OP496HRU –40°C to +125°C 14-Lead Plastic DIP N-14 14-Lead SOIC SO-14 14-Lead TSSOP RU-14 NOTES 1 Absolute maximum ratings apply to both DICE and packaged parts, unless otherwise noted. 2 For supply voltages less than +15 V, the absolute maximum input voltage is equal to the supply voltage. 3 θ JA is specified for the worst case conditions, i.e., θJA is specified for device in socket for P-DIP package; θ JA is specified for device soldered in circuit board for SOIC and TSSOP packages. 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 OP196/OP296/OP496 feature proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, pro per ESD precautions are recommended to avoid performance degradation or loss of functionality. REV. B –5– WARNING! ESD SENSITIVE DEVICE OP196/OP296/OP496–Typical Performance Characteristics 25 250 150 100 0 –250 –200 –150 –100 –50 0 50 100 150 INPUT OFFSET VOLTAGE – mV 200 1.0 25 VS = 15V TA = 1258C COUNT = 400 VS = 112V VCM = 16V TA = –408C TO 11258C 20 QUANTITY – Amplifiers QUANTITY – Amplifiers –3.0 –2.5 –2.0 –1.5 –1.0 –0.5 0 0.5 INPUT OFFSET DRIFT, TCVOS – mV/8C Figure 4. Input Offset Voltage Distribution (TCVOS ) 250 150 100 15 10 5 50 0 –250 –200 –150 –100 –50 0 50 100 150 INPUT OFFSET VOLTAGE – mV 200 0 –4.0 –3.5 –3.0 –2.5 –2.0 –1.5 –1.0 –0.5 0 0.5 INPUT OFFSET DRIFT, TCVOS – mV/8C 250 Figure 2. Input Offset Voltage Distribution 1.0 1.5 Figure 5. Input Offset Voltage Distribution (TCVOS ) 250 600 VS = 112V TA = 1258C COUNT = 400 INPUT OFFSET VOLTAGE – mV QUANTITY – Amplifiers 10 0 –4.0 –3.5 250 Figure 1. Input Offset Voltage Distribution 200 15 5 50 200 VS = 15V VCM = 12.5V TA = –408C TO 11258C 20 QUANTITY – Amplifiers QUANTITY – Amplifiers 200 VS = 13V TA = 1258C COUNT = 400 150 100 50 0 –250 –200 –150 –100 –50 0 50 100 150 INPUT OFFSET VOLTAGE – mV 13V 400 VCM = VS VS 2 112V 200 0 –200 200 –400 –75 250 Figure 3. Input Offset Voltage Distribution –50 –25 0 25 50 75 TEMPERATURE – 8C 100 125 150 Figure 6. Input Offset Voltage vs. Temperature –6– REV. B OP196/OP296/OP496 25 1000 VS = 15V VCM = 12.5V VS = 61.5V OUTPUT VOLTAGE – mV INPUT BAIS CURRENT – nA 20 15 10 –50 –25 0 25 50 75 TEMPERATURE – 8C 100 125 SINK 10 1 0.001 150 Figure 7. Input Bias Current vs. Temperature 0.01 0.1 1 LOAD CURRENT – mA 10 Figure 10. Output Voltage to Supply Rail vs. Load Current 16 1000 VS = 62.5V OUTPUT VOLTAGE – mV INPUT BIAS CURRENT – nA SOURCE 5 0 –75 12 8 4 2 3 12 5 SUPPLY VOLTAGE – Volts SOURCE SINK 10 0.01 0.1 1 LOAD CURRENT – mA 10 Figure 11. Output Voltage to Supply Rail vs. Load Current 40 30 100 1 0.001 14 Figure 8. Input Bias Current vs. Supply Voltage 1000 VS = 62.5V TA = 1258C VS = 66V 20 OUTPUT VOLTAGE – mV INPUT BIAS CURRENT – nA 100 10 0 –10 –20 100 SOURCE SINK 10 –30 –40 –2.5 –2.0 –1.5 –1.0 –0.5 0 0.5 1.0 1.5 COMMON-MODE VOLTAGE – Volts 2.0 1 0.001 2.5 Figure 9. Input Bias Current vs. Common-Mode Voltage REV. B 0.01 0.1 1 LOAD CURRENT – mA 10 Figure 12. Output Voltage to Supply Rail vs. Load Current –7– OP196/OP296/OP496–Typical Performance Characteristics 4.95 90 I L = 100mA VS = 62.5V TA = –408C 4.70 70 OPEN-LOOP GAIN – dB 4.45 I L = 2mA 4.2 VS = 15V 60 GAIN 50 –50 –25 0 25 50 75 TEMPERATURE – 8C 100 125 10 135 0 180 1k 10k FREQUENCY – Hz 100 225 1M 100k 90 VS = 62.5V TA = 11258C 80 0.60 70 I L = –1mA OPEN-LOOP GAIN – dB VOL OUTPUT VOLTAGE – Volts 90 Figure 16. Open-Loop Gain and Phase vs. Frequency (No Load) VS = 15V 0.50 0.30 0.10 60 GAIN 50 40 0 30 45 90 20 PHASE 135 10 –50 –25 0 25 50 75 TEMPERATURE – 8C 180 0 I L = –100mA 100 125 –10 10 150 Figure 14. Output Voltage Swing vs. Temperature 1k 10k FREQUENCY – Hz 100 225 1M 100k Figure 17. Open-Loop Gain and Phase vs. Frequency (No Load) 90 950 VS = 15V VS = 62.5V TA = 1258C 80 0.3V < VO < 4.7V RL = 100kV 800 70 OPEN-LOOP GAIN – V/mV 60 GAIN 50 40 0 30 45 20 90 PHASE 10 135 0 180 100 1k 10k FREQUENCY – Hz 100k PHASE SHIFT – 8C OPEN-LOOP GAIN – dB 45 PHASE 0.80 –10 10 30 –10 10 150 Figure 13. Output Voltage Swing vs. Temperature –75 0 20 3.85 3.7 –75 40 PHASE SHIFT – 8C I L = 1mA PHASE SHIFT – 8C VOH OUTPUT VOLTAGE – Volts 80 225 1M 650 500 350 200 –75 Figure 15. Open-Loop Gain and Phase vs. Frequency (No Load) –50 –25 0 25 50 75 TEMPERATURE – 8C 100 125 150 Figure 18. Open-Loop Gain vs. Temperature –8– REV. B OP196/OP296/OP496 600 160 OPEN-LOOP GAIN – V/mV 500 VS = 15V 140 TA = 1258C 120 VS = 62.5V TA = 1258C ALL CHANNELS 100 80 CMRR – dB 400 300 200 60 40 20 0 100 –20 0 150 100 50 10 LOAD – kV 2 –40 100 1 Figure 19. Open Loop Gain vs. Resistive Load 10k 100k FREQUENCY – Hz 10M 160 VS = 62.5V RL = 10kV TA = 1258C 60 50 VS = 15V TA = 1258C 140 120 40 PSRR – dB 100 30 20 10 80 +PSRR 60 40 –PSRR 0 20 –10 0 –20 –20 –30 10 1k 10k FREQUENCY – Hz 100 100k –40 10 1M Figure 20. Closed-Loop Gain vs. Frequency 100 1k 10k 100k FREQUENCY – Hz 10M 6 VS = 62.5V VIN = 15V p-p AV = 11 RL = 100kV 900 VS = 62.5V TA = 1258C MAXIMUM OUTPUT SWING – Volts 800 1M Figure 23. PSRR vs. Frequency 1000 OUTPUT IMPEDANCE – V 1M Figure 22. CMRR vs. Frequency 70 CLOSED-LOOP GAIN – dB 1k 700 600 ACL = 10 500 400 ACL = 1 300 200 5 4 3 2 1 100 0 100 1k 10k FREQUENCY – Hz 100k 0 1k 1M Figure 21. Output Impedance vs. Frequency REV. B 10k 100k FREQUENCY – Hz 1M Figure 24. Maximum Output Swing vs. Frequency –9– OP196/OP296/OP496–Typical Performance Characteristics 90 0.6 CURRENT NOISE DENSITY – pA/ Hz ISY/AMPLIFIER – mA 80 70 VS = 112V 60 50 VS = 15V 40 VS = 13V 30 20 –75 –50 –40 –25 0 25 50 85 75 TEMPERATURE – 8C 0.4 0.3 0.2 0.1 0 1 100 125 150 Figure 25. Supply Current/Amplifier vs. Temperature VS = 62.5V TA = 1258C VCM = 0V 0.5 10 1k 100 FREQUENCY – Hz Figure 28. Input Bias Current Noise Density vs. Frequency 55 10 TA = 1258C 8 6 50 VS = 66V TA = 1258C TO 0.1% 1OUTPUT SWING INPUT STEP – Volts ISY/AMPLIFIER – mA 4 45 40 2 0 –2 –4 – OUTPUT SWING –6 –8 35 1 3 5 7 9 11 SUPPLY VOLTAGE – Volts 12 –10 0 13 Figure 26. Supply Current/Amplifier vs. Supply Voltage 5 10 15 20 SETTLING TIME – ms 25 30 Figure 29. Settling Time to 0.1% vs. Step Size VOLTAGE NOISE DENSITY – nV/ Hz 80 VS = 62.5V TA = 1258C VCM = 0V 70 2mV 60 1s 100 90 50 40 30 10 20 0% 10 0 1 10 100 FREQUENCY – Hz VS = 62.5V AV = 10k en = 0.8mV p-p 1k Figure 27. Voltage Noise Density vs. Frequency Figure 30. 0.1 Hz to 10 Hz Noise –10– REV. B OP196/OP296/OP496 100mV 100 90 VS = 2.5V AV = 1 RL = 10kV CL = 100pF TA = 1258C 10 0V 0% 20mV 10 0% 2ms Figure 33. Large Signal Transient Response VS = 62.5V RL = 100kV 100 90 100 90 VS = 62.5V AV = 1 RL = 100kV CL = 100pF TA = 1258C 10 0V 10ms 1V Figure 31. Small Signal Transient Response 100mV VS = 62.5V RL = 10kV 100 90 0% 20mV 10 0% 10ms 1V 2ms Figure 32. Small Signal Transient Response Figure 34. Large Signal Transient Response CH A: 40.0mV FS MKR: 36.8mV/ Hz 5.00mV/DIV 10Hz 0Hz MKR: 1.00Hz BW: 145mHz Figure 35. 1/f Noise Corner, VS = ± 5 V, AV = 1,000 VCC R1 R2 I1 R7 R6 R8 I4 D3 Q17 D8 QC1 Q4 1x Q2 CF2 Q14 Q8 D5 Q10 Q9 2x OUT CF1 Q13 2x Q21 CC2 1x 1x 1x Q7 Q1 D4 2x Q3 +IN Q12 Q6 Q5 2x Q22 D9 QL1 Q11 I5 Q18 D6 2x QC2 Q19 1x Q23 R5 –IN R3A R3B CC1 R4A R9 I3 I2 Q16 Q15 R4B D7 1.5x D10 1x VEE 1* 5* *OP196 ONLY Figure 36. Simplified Schematic REV. B Q20 –11– OP196/OP296/OP496 The OP196 family of operational amplifiers is comprised of singlesupply, micropower, rail-to-rail input and output amplifiers. Input offset voltage (VOS) is only 300 µV maximum, while the output will deliver ±5 mA to a load. Supply current is only 50 µA, while bandwidth is over 450 kHz and slew rate is 0.3 V/µs. Figure 36 is a simplified schematic of the OP196—it displays the novel circuit design techniques used to achieve this performance. input current must be limited if the inputs are driven beyond the supply rails. In the circuit of Figure 38, the source amplitude is ± 15 V, while the supply voltage is only ± 5 V. In this case, a 2 kΩ source resistor limits the input current to 5 mA. 5V VOLTAGE – 5V/DIV APPLICATIONS INFORMATION Functional Description Input Overvoltage Protection The OPx96 family of op amps uses a composite PNP/NPN input stage. Transistor Q1 in Figure 36 has a collector-base voltage of 0 V if +IN = VEE. If +IN then exceeds VEE, the junction will be forward biased and large diode currents will flow, which may damage the device. The same situation applies to +IN on the base of transistor Q5 being driven above VCC . Therefore, the inverting and noninverting inputs must not be driven above or below either supply rail unless the input current is limited. Figure 37 shows the input characteristics for the OPx96 family. This photograph was generated with the power supply pins connected to ground and a curve tracer’s collector output drive connected to the input. As shown in the figure, when the input voltage exceeds either supply by more than 0.6 V, internal pnjunctions energize and permit current flow from the inputs to the supplies. If the current is not limited, the amplifier may be damaged. To prevent damage, the input current should be limited to no more than 5 mA. VS = 5V AV = 1 100 90 VIN 0 VOUT 0 10 0% 5V 1ms TIME – 1ns/DIV Figure 38. Output Voltage Phase Reversal Behavior Input Offset Voltage Nulling The OP196 provides two offset adjust terminals that can be used to null the amplifier’s internal VOS. In general, operational amplifier terminals should never be used to adjust system offset voltages. A 100 kΩ potentiometer, connected as shown in Figure 39, is recommended to null the OP196’s offset voltage. Offset nulling does not adversely affect TCVOS performance, providing that the trimming potentiometer temperature coefficient does not exceed ± 100 ppm/°C. V+ 8 INPUT CURRENT – mA 100 4 7 2 6 OP196 90 5 1 0 100kV –2 –4 6 4 3 2 V– 10 0% –6 Figure 39. Offset Nulling Circuit –8 –1.5 –1 –0.5 0 0.5 1 1.5 INPUT VOLTAGE – Volts Figure 37. Input Overvoltage I-V Characteristics of the OPx96 Family Driving Capacitive Loads OP196 family amplifiers are unconditionally stable with capacitive loads less than 170 pF. When driving large capacitive loads in unity-gain configurations, an in-the-loop compensation technique is recommended, as illustrated in Figure 40. Output Phase Reversal RG RF VIN Some other operational amplifiers designed for single-supply operation exhibit an output voltage phase reversal when their inputs are driven beyond their useful common-mode range. Typically for single-supply bipolar op amps, the negative supply determines the lower limit of their common-mode range. With these common-mode limited devices, external clamping diodes are required to prevent input signal excursions from exceeding the device’s negative supply rail (i.e., GND) and triggering output phase reversal. CF RX OP296 VOUT CL RX = RO RG RF WHERE RO = OPEN-LOOP OUTPUT RESISTANCE CF = The OPx96 family of op amps is free from output phase reversal effects due to its novel input structure. Figure 38 illustrates the performance of the OPx96 op amps when the input is driven beyond the supply rails. As previously mentioned, amplifier I+ ( | AICL| ) ( RFR+ RG ) CL RO F Figure 40. In-the-Loop Compensation Technique for Driving Capacitive Loads –12– REV. B OP196/OP296/OP496 A Micropower False-Ground Generator Some single supply circuits work best when inputs are biased above ground, typically at 1/2 of the supply voltage. In these cases, a false-ground can be created by using a voltage divider buffered by an amplifier. One such circuit is shown in Figure 41. This circuit will generate a false-ground reference at 1/2 of the supply voltage, while drawing only about 55 µA from a 5 V supply. The circuit includes compensation to allow for a 1 µF bypass capacitor at the false-ground output. The benefit of a large capacitor is that not only does the false-ground present a very low dc resistance to the load, but its ac impedance is low as well. +5V OR +12V 10kV 0.022mF 240kV 2 7 100V OP196 1mF 4 3 240kV +2.5V OR +6V 6 1mF Figure 41. A Micropower False-Ground Generator Single-Supply Half-Wave and Full-Wave Rectifiers An OP296, configured as a voltage follower operating from a single supply, can be used as a simple half-wave rectifier in low frequency (<400 Hz) applications. A full-wave rectifier can be configured with a pair of OP296s as illustrated in Figure 42. same potential. The result is that both terminals of R1 are at the same potential and no current flows in R1. Since there is no current flow in R1, the same condition must exist in R2; thus, the output of the circuit tracks the input signal. When the input signal is below 0 V, the output voltage of A1 is forced to 0 V. This condition now forces A2 to operate as an inverting voltage follower because the noninverting terminal of A2 is also at 0 V. The output voltage of VOUTA is then a full-wave rectified version of the input signal. A resistor in series with A1’s noninverting input protects the ESD diodes when the input signal goes below ground. Square Wave Oscillator The oscillator circuit in Figure 43 demonstrates how a rail-torail output swing can reduce the effects of power supply variations on the oscillator’s frequency. This feature is especially valuable in battery powered applications, where voltage regulation may not be available. The output frequency remains stable as the supply voltage changes because the RC charging current, which is derived from the rail-to-rail output, is proportional to the supply voltage. Since the Schmitt trigger threshold level is also proportional to supply voltage, the frequency remains relatively independent of supply voltage. For a supply voltage change from 9 V to 5 V, the output frequency only changes about 4 Hz. The slew rate of the amplifier limits the oscillation frequency to a maximum of about 200 Hz at a supply voltage of +5 V. V+ 100kV 59kV R2 100kV R1 100kV 3 8 2 4 1 100kV +5V +2Vp-p <500Hz 6 2kV A2 8 3 A1 1 4 2 5 1/2 OP296 7 1/2 OP296 VOUTA FULL-WAVE RECTIFIED OUTPUT VOUTB HALF-WAVE RECTIFIED OUTPUT R 1/2 OP296/ OP496 FREQ OUT fOSC = 1 < 200Hz @ V+ = +5V RC C Figure 43. Square Wave Oscillator Has Stable Frequency Regardless of Supply Voltage Changes A 3 V Low Dropout, Linear Voltage Regulator 1V INPUT 500mV 500µs 100 90 VOUTB (HALF-WAVE OUTPUT) f = 500Hz 10 VOUTA (FULL-WAVE OUTPUT) 0% 500mV Figure 42. Single-Supply Half-Wave and Full-Wave Rectifiers Using an OP296 The circuit works as follows: When the input signal is above 0 V, the output of amplifier A1 follows the input signal. Since the noninverting input of amplifier A2 is connected to A1’s output, op amp loop control forces A2’s inverting input to the REV. B Figure 44 shows a simple +3 V voltage regulator design. The regulator can deliver 50 mA load current while allowing a 0.2 V dropout voltage. The OP296’s rail-to-rail output swing easily drives the MJE350 pass transistor without requiring special drive circuitry. With no load, its output can swing to less than the pass transistor’s base-emitter voltage, turning the device nearly off. At full load, and at low emitter-collector voltages, the transistor beta tends to decrease. The additional base current is easily handled by the OP296 output. The AD589 provides a 1.235 V reference voltage for the regulator. The OP296, operating with a noninverting gain of 2.43, drives the base of the MJE350 to produce an output voltage of 3.0 V. Since the MJE350 operates in an inverting (commonemitter) mode, the output feedback is applied to the OP296’s noninverting input. –13– OP196/OP296/OP496 IL < 50mA MJE 350 VO VIN 5V TO 3.2V 44.2kV 1% 8 1 100mF 3 1/2 OP296 30.9kV 1% 2 4 1000pF 43kV 1.235V AD589 Figure 44. 3 V Low Dropout Voltage Regulator Figure 45 shows the regulator’s recovery characteristics when its output underwent a 20 mA to 50 mA step current change. 2V STEP 50mA CURRENT CONTROL WAVEFORM 30mA OUTPUT 100 90 The next two DACs, B and C, sum their outputs into the other OP296 amplifier. In this circuit DAC C provides the coarse output voltage setting and DAC B is used for fine adjustment. The insertion of R1 in series with DAC B attenuates its contribution to the voltage sum node at the DAC C output. A High-Side Current Monitor In the design of power supply control circuits, a great deal of design effort is focused on ensuring a pass transistor’s long-term reliability over a wide range of load current conditions. As a result, monitoring and limiting device power dissipation is of prime importance in these designs. The circuit illustrated in Figure 47 is an example of a +5 V, single-supply high-side current monitor that can be incorporated into the design of a voltage regulator with fold-back current limiting or a high current power supply with crowbar protection. This design uses an OP296’s rail-to-rail input voltage range to sense the voltage drop across a 0.1 Ω current shunt. A p-channel MOSFET is used as the feedback element in the circuit to convert the op amp’s differential input voltage into a current. This current is then applied to R2 to generate a voltage that is a linear representation of the load current. The transfer equation for the current monitor is given by: R Monitor Output = R2 × SENSE × I L R1 10 0% 10mV 50µs Figure 45. Output Step Load Current Recovery For the element values shown, the Monitor Output’s transfer characteristic is 2.5 V/A. Buffering a DAC Output RSENSE 0.1V Multichannel TrimDACs® such as the AD8801/AD8803, are widely used for digital nulling and similar applications. These DACs have rail-to-rail output swings, with a nominal output resistance of 5 kΩ. If a lower output impedance is required, an OP296 amplifier can be added. Two examples are shown in Figure 45. One amplifier of an OP296 is used as a simple buffer to reduce the output resistance of DAC A. The OP296 provides rail-to-rail output drive while operating down to a 3 V supply and requiring only 50 µA of supply current. R1 100V 3 8 1/2 OP296 2 1 4 S G M1 3N163 MONITOR OUTPUT D R2 2.49kV Figure 47. A High-Side Load Current Monitor OP296 A Single-Supply RTD Amplifier VH VL SIMPLE BUFFER 0V TO +5V +4.983V +1.1mV VH VL R1 100kV VH VL AD8801/ AD8803 VREFL +5V +5V +5V VREFH VDD IL +5V SUMMER CIRCUIT WITH FINE TRIM ADJUSTMENT GND DIGITAL INTERFACING OMITTED FOR CLARITY Figure 46. Buffering a TrimDAC Output The circuit in Figure 48 uses three op amps on the OP496 to produce a bridge driver for an RTD amplifier while operating from a single +5 V supply. The circuit takes advantage of the OP496’s wide output swing to generate a bridge excitation voltage of 3.9 V. An AD589 provides a 1.235 V reference for the bridge current. Op amp A1 drives the bridge to maintain 1.235 V across the parallel combination of the 6.19 kΩ and 2.55 MΩ resistors, which generates a 200 µA current source. This current divides evenly and flows through both halves of the bridge. Thus, 100 µA flows through the RTD to generate an output voltage which is proportional to its resistance. For improved accuracy, a 3-wire RTD is recommended to balance the line resistance in both 100 Ω legs of the bridge. TrimDAC is a registered trademark of Analog Devices Inc. –14– REV. B OP196/OP296/OP496 GAIN = 259 200V 10-TURNS +5V 26.7kV 26.7kV 100V RTD 100V 2.55MV A1 AD589 37.4kV A3 392V 392V 100kV VOUT A2 1/4 OP496 6.17kV 1/4 OP496 1/4 OP496 Amplifiers A2 and A3 are configured in a two op amp instrumentation amplifier configuration. For ease of measurement, the IA resistors are chosen to produce a gain of 259, so that each 1°C increase in temperature results in a 10 mV increase in the output voltage. To reduce measurement noise, the bandwidth of the amplifier is limited. A 0.1 µF capacitor, connected in parallel with the 100 kΩ resistor on amplifier A3, creates a pole at 16 Hz. 20kV 100kV 0.1mF NOTE: ALL RESISTORS 1% OR BETTER +5V Figure 48. A Single Supply RTD Amplifier * OP496 SPICE Macro-model REV. B, 5/95 * ARG / ADSC * * Copyright 1995 by Analog Devices * * Refer to “README.DOC” file for License Statement. * Use of this model indicates your acceptance of the * terms and provisions in the License Statement. * * Node assignments * Noninverting input * Inverting input * Positive supply * Negative supply * Output * * .SUBCKT OP496 1 2 99 50 49 * * INPUT STAGE * IREF 21 50 1U QB1 21 21 99 99 QP 1 QB2 22 21 99 99 QP 1 QB3 4 21 99 99 QP 1.5 QB4 22 22 50 50 QN 2 QB5 11 22 50 50 QN 3 Q1 5 4 7 50 QN 2 Q2 6 4 8 50 QN 2 Q3 4 4 7 50 QN 1 Q4 4 4 8 50 QN 1 Q5 50 1 7 99 QP 2 Q6 50 3 8 99 QP 2 EOS 3 2 POLY(1) (17,98) 35U 1 Q7 99 1 9 50 QN 2 Q8 99 3 10 50 QN 2 Q9 12 11 9 99 QP 2 Q10 13 11 10 99 QP 2 Q11 11 11 9 99 QP 1 Q12 11 11 10 99 QP 1 R1 99 5 50K R2 99 6 50K R3 12 50 50K R4 13 50 50K IOS 1 2 0.75N C10 5 6 3.183P C11 12 13 3.183P REV. B CIN 1 2 1P * * GAIN STAGE * EREF 98 0 POLY(2) (99,0) (50,0) 0 G1 98 15 POLY(2) (6,5) (13,12) 0 R10 15 98 251.641MEG CC 15 49 8P D1 15 99 DX D2 50 15 DX * * COMMON MODE STAGE * ECM 16 98 POLY(2) (1,98) (2,98) 0 R11 16 17 1MEG R12 17 98 10 * * OUTPUT STAGE * ISY 99 50 20U EIN 35 50 POLY(1) (15,98) 1.42735 Q24 37 35 36 50 QN 1 QD4 37 37 38 99 QP 1 Q27 40 37 38 99 QP 1 R5 36 39 150K R6 99 38 45K Q26 39 42 50 50 QN 3 QD5 40 40 39 50 QN 1 Q28 41 40 44 50 QN 1 QL1 37 41 99 99 QP 1 R7 99 41 10.7K I4 99 43 2U QD7 42 42 50 50 QN 2 QD6 43 43 42 50 QN 2 Q29 47 43 44 50 QN 1 Q30 44 45 50 50 QN 1.5 QD10 45 46 50 50 QN 1 R9 45 46 175 Q31 46 47 48 99 QP 1 QD8 47 47 48 99 QP 1 QD9 48 48 51 99 QP 5 R8 99 51 2.9K I5 99 46 1U Q32 49 48 99 99 QP 10 Q33 49 44 50 50 QN 4 .MODEL DX D() .MODEL QN NPN(BF=120VAF=100) .MODEL QP PNP(BF=80 VAF=60) .ENDS –15– 0.5 0.5 10U 10U 0.5 0.5 1 OP196/OP296/OP496 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 14-Lead Plastic DIP (N-14) 0.430 (10.92) 0.348 (8.84) 8 0.795 (20.19) 0.725 (18.42) 5 1 0.280 (7.11) 0.240 (6.10) 4 0.060 (1.52) 0.015 (0.38) PIN 1 0.210 (5.33) MAX 14 8 1 7 0.325 (8.25) 0.300 (7.62) 0.130 (3.30) MIN SEATING 0.022 (0.558) 0.070 (1.77) PLANE 0.100 0.014 (0.356) (2.54) 0.045 (1.15) BSC 0.160 (4.06) 0.115 (2.93) 0.210 (5.33) MAX 0.130 (3.30) MIN 0.160 (4.06) 0.115 (2.93) 0.015 (0.381) 0.008 (0.204) 5 1 4 SEATING PLANE 0.3444 (8.75) 0.3367 (8.55) 0.2440 (6.20) 0.2284 (5.80) 0.1574 (4.00) 0.1497 (3.80) 0.0688 (1.75) 0.0532 (1.35) 0.0500 0.0192 (0.49) (1.27) 0.0138 (0.35) BSC 0.0196 (0.50) x 45° 0.0099 (0.25) 0.0098 (0.25) 0.0075 (0.19) 8° 0° 14 8 1 7 0.0500 (1.27) BSC SEATING PLANE 8-Lead TSSOP (RU-8) 8° 0° 0.0500 (1.27) 0.0160 (0.41) 0.201 (5.10) 0.193 (4.90) 0.256 (6.50) 0.246 (6.25) 0.256 (6.50) 0.246 (6.25) 4 1 0.0256 (0.65) 0.006 (0.15) BSC 0.002 (0.05) 0.0118 (0.30) 0.0075 (0.19) 8 0.177 (4.50) 0.169 (4.30) 14 PIN 1 SEATING PLANE 0.0099 (0.25) 0.0075 (0.19) 5 0.177 (4.50) 0.169 (4.30) 1 0.0192 (0.49) 0.0138 (0.35) 0.0196 (0.50) x 45° 0.0099 (0.25) 14-Lead TSSOP (RU-14) 0.122 (3.10) 0.114 (2.90) 8 0.0688 (1.75) 0.0532 (1.35) PIN 1 0.0098 (0.25) 0.0040 (0.10) 0.0500 (1.27) 0.0160 (0.41) 0.2440 (6.20) 0.2284 (5.80) PRINTED IN U.S.A. PIN 1 0.0098 (0.25) 0.0040 (0.10) 0.015 (0.381) 0.008 (0.204) SEATING PLANE 14-Lead Narrow-Body SOIC (SO-14) 0.1968 (5.00) 0.1890 (4.80) 8 0.100 0.070 (1.77) (2.54) 0.045 (1.15) BSC 0.022 (0.558) 0.014 (0.356) 8-Lead Narrow Body SOIC (SO-8) 0.1574 (4.00) 0.1497 (3.80) 0.325 (8.25) 0.300 (7.62) 0.195 (4.95) 0.115 (2.93) 0.060 (1.52) 0.015 (0.38) PIN 1 0.195 (4.95) 0.115 (2.93) 0.280 (7.11) 0.240 (6.10) C2051b–0–2/98 8-Lead Plastic DIP (N-8) 7 PIN 1 0.0433 (1.10) MAX 0.0079 (0.20) 0.0035 (0.090) 8° 0° 0.006 (0.15) 0.002 (0.05) 0.028 (0.70) 0.020 (0.50) SEATING PLANE –16– 0.0433 (1.10) MAX 0.0256 (0.65) BSC 0.0118 (0.30) 0.0075 (0.19) 0.0079 (0.20) 0.0035 (0.090) 8° 0° 0.028 (0.70) 0.020 (0.50) REV. B