Dual/Quad Single-Supply Operational Amplifiers OP292/OP492 APPLICATIONS Disk drives Mobile phones Servo controls Modems and fax machines Pagers Power supply monitors and controls Battery-operated instrumentation PIN CONFIGURATIONS OUTA 1 -INA 2 OP292 +INA 3 TOP VIEW -V 4 (Not to Scale) 8 +V 7 OUTB 6 -INB 5 +INB 00310-00 Single-supply operation: 4.5 V to 33 V Input common-mode includes ground Output swings to ground High slew rate: 3 V/s High gain bandwidth: 4 MHz Low input offset voltage High open-loop gain No phase inversion Figure 1. 8-Lead Narrow-Body SOIC (S-Suffix) OUTA 1 14 OUTD -INA 2 13 -IND 12 +IND +INA 3 OP492 TOP VIEW 11 -V (Not to Scale) 10 +INC +INB 5 +V 4 -INB 6 9 -INC OUTB 7 8 OUTC 00310-002 FEATURES Figure 2. 14-Lead Narrow-Body SOIC (S-Suffix) GENERAL DESCRIPTION The OP292/OP492 are low cost, general-purpose dual and quad operational amplifiers designed for single-supply applications and are ideal for 5 V systems. Fabricated on Analog Devices, Inc., CBCMOS process, the OP292/OP492 series has a PNP input stage that allows the input voltage range to include ground. A BiCMOS output stage enables the output to swing to ground while sinking current. The OP292/OP492 series is unity-gain stable and features an outstanding combination of speed and performance for singleor dual-supply operation. The OP292/OP492 provide a high slew rate, high bandwidth, with open-loop gain exceeding 40,000 and offset voltage under 800 (OP292) and 1 mV (OP492). With these combinations of features and low supply current, the OP292/OP492 series is an excellent choice for battery-operated applications. The OP292/OP492 series performance is specified for single- or dual-supply voltage operation over the extended industrial temperature range (-40C to +125C). Rev. C 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. Specifications subject to change without notice. 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 owners. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 www.analog.com Fax: 781.461.3113 (c)1993-2009 Analog Devices, Inc. All rights reserved. OP292/OP492 TABLE OF CONTENTS Features .............................................................................................. 1 Typical Applications ....................................................................... 14 Applications ....................................................................................... 1 Direct Access Arrangement for Telephone Line Interface ... 14 Pin Configurations ........................................................................... 1 Single-Supply Instrumentation Amplifier .............................. 14 General Description ......................................................................... 1 DAC Output Amplifier .............................................................. 14 Revision History ............................................................................... 2 50 Hz/60 Hz Single-Supply Notch Filter ................................. 15 Specifications..................................................................................... 3 Four-Pole Bessel Low-Pass Filter ............................................. 15 Electrical Characteristics ............................................................. 3 Low Cost, Linearized Thermistor Amplifier.............................. 15 Absolute Maximum Ratings............................................................ 6 Thermal Resistance ...................................................................... 6 Single-Supply Ultrasonic Clamping/Limiting Receiver Amplifier ..................................................................................... 16 ESD Caution .................................................................................. 6 Precision Single-Supply Voltage Comparator ........................ 16 Typical Performance Characteristics ............................................. 7 Programmable Precision Window Comparator .................... 16 Applications Information .............................................................. 13 Outline Dimensions ....................................................................... 17 Phase Reversal ............................................................................. 13 Ordering Guide .......................................................................... 17 Power Supply Considerations ................................................... 13 REVISION HISTORY 5/09--Rev. B to Rev. C Deleted 8-Lead PDIP and 14-Lead PDIP ........................ Universal Changes to Features Section and General Description Section . 1 Changed VS = 5 V to VS = 15 V .................................................... 4 Changes to Table 3 and Table 4 ....................................................... 6 Changes to Figure 21 Caption and Figure 24 Caption .............. 10 Changes to Figure 29 ...................................................................... 11 Changes to Figure 35 ...................................................................... 13 Deleted OP292 SPICE Macro-model Section............................. 14 Changes to Figure 38 ...................................................................... 14 Changes to Figure 39 and Figure 41 ............................................. 15 Deleted OP492 SPICE Macro-model Section............................. 16 Changes to Figure 44 ...................................................................... 16 Updated Outline Dimensions ....................................................... 17 Changes to Ordering Guide .......................................................... 17 10/02--Rev. A to Rev. B Edits to Outline Dimensions ......................................................... 18 1/02--Rev. 0 to Rev. A Deleted Wafer Test Limits ............................................................... 4 Deleted Dice Characteristics ........................................................... 4 Edits to Ordering Guide ................................................................ 20 Rev. C | Page 2 of 20 OP292/OP492 SPECIFICATIONS ELECTRICAL CHARACTERISTICS VS = 5 V, VCM = 0 V, VO = 2 V, TA = 25C, unless otherwise noted. Table 1. Parameter INPUT CHARACTERISTICS Offset Voltage OP292 Symbol Conditions Min VOS -40C TA +85C -40C TA +125C OP492 VOS -40C TA +85C -40C TA +125C Input Bias Current IB -40C TA +85C -40C TA +125C Input Offset Current IOS -40C TA +85C -40C TA +125C Input Voltage Range Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain AVO Offset Voltage Drift Long-Term VOS Drift 1 Bias Current Drift VOS/T VOS/T IB/T Offset Current Drift IOS/T OUTPUT CHARACTERISTICS Output Voltage Swing High Low Short-Circuit Current Limit POWER SUPPLY Power Supply Rejection Ratio Supply Current Per Amp VOUT VOUT VCM = 0 V to 4.0 V -40C TA +85C -40C TA +125C RL = 10 k, VO = 0.1 V to 4 V -40C TA +85C -40C TA +125C -40C TA +125C -40C TA +85C -40C TA +125C -40C TA +85C -40C TA +125C RL = 100 k to GND -40C TA +125C RL = 2 k to GND -40C TA +125C RL = 100 k to V+ -40C TA +125C RL = 2 k to V+ -40C TA +125C ISC PSRR ISY 0 75 70 65 25 10 5 4.0 3.8 3.7 5 VS = 4.5 V to 30 V, VO = 2 V -40C TA +125C VO = 2 V Rev. C | Page 3 of 20 75 70 Typ Max Unit 0.1 0.3 0.5 0.1 0.3 0.5 450 0.75 3.0 7 100 0.4 0.8 1.2 2.5 1 1.5 2.5 700 2.5 5.0 50 700 1.2 4.0 mV mV mV mV mV mV nA A A nA nA A V dB dB dB V/mV V/mV V/mV V/C V/Month pA/C pA/C pA/C pA/C 95 93 90 200 100 50 2 1 6 400 1.5 2 4.3 4.1 3.9 8 12 280 300 8 95 90 0.8 10 20 20 450 550 1.2 V V V mV mV mV mV mA dB dB mA OP292/OP492 Parameter Symbol Conditions Min DYNAMIC PERFORMANCE Slew Rate SR RL = 10 k -40C TA +125C 1 Gain Bandwidth Product Phase Margin Channel Separation NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density 1 GBP m CS en p-p en in fO = 1 kHz 0.1 Hz to 10 Hz f = 1 kHz Typ Max Unit 3 2 4 75 100 V/s V/s MHz Degrees dB 25 15 0.7 V p-p nV/Hz pA/Hz Long-term offset voltage drift is guaranteed by 1,000 hours life test performed on three independent wafer lots at 125C with LTPD of 1.3. VS =15 V, VCM = 0 V, VO = 2 V, TA = 25C, unless otherwise noted. Table 2. Parameter INPUT CHARACTERISTICS Offset Voltage OP292 Symbol Conditions Min VOS -40C TA +85C -40C TA +125C OP492 VOS -40C TA +85C -40C TA +125C Input Bias Current IB Input Offset Current IOS -40C TA +125C -40C TA +85C -40C TA +125C Input Voltage Range 1 Common-Mode Rejection Ratio CMRR Large Signal Voltage Gain AVO Offset Voltage Drift Bias Current Drift OUTPUT CHARACTERISTICS Output Voltage Swing Short-Circuit Current Limit POWER SUPPLY Power Supply Rejection Ratio Supply Current Per Amp VOS/T IB/T VO ISC PSRR ISY VCM = 11 V -40C TA +125C RL = 10 k, VO =10 V -40C TA +85C -40C TA +125C -40C TA +125C -40C TA +125C -11 78 75 25 10 5 Typ Max Unit 1.0 1.2 1.5 1.4 1.7 2 375 0.5 7 20 0.4 2.0 2.5 3 2.5 2.8 3 700 1 50 100 1.2 +11 mV mV mV mV mV mV nA A nA nA A V dB dB V/mV V/mV V/mV V/C pA/C 100 95 120 75 60 4 3 10 RL = 2 k to GND -40C TA +125C RL = 100 k to GND -40C TA +125C Short circuit to GND 11 10 13.8 13.5 8 12.2 11 14.3 14.0 10.5 V V V mV mA VS = 2.25 V to 15 V -40C TA +125C VO = 0 V 75 70 86 83 1 dB dB mA Rev. C | Page 4 of 20 1.4 OP292/OP492 Parameter DYNAMIC PERFORMANCE Slew Rate Symbol Conditions Min Typ SR RL =10 k -40C TA +125C 2.5 2 Gain Bandwidth Product Phase Margin Channel Separation NOISE PERFORMANCE Voltage Noise Voltage Noise Density Current Noise Density GBP m CS 4 3 4 75 100 V/s V/s MHz Degrees dB 25 15 0.7 V p-p nV/Hz pA/Hz 1 en p-p en in fO = 1 kHz 0.1 Hz to 10 Hz f = 1 kHz Input voltage range is guaranteed by CMRR tests. Rev. C | Page 5 of 20 Max Unit OP292/OP492 ABSOLUTE MAXIMUM RATINGS Table 3. Parameter Supply Voltage Input Voltage Range 1 Differential Input Voltage1 Output Short-Circuit Duration Storage Temperature Range Operating Temperature Range Junction Temperature Range Lead Temperature Range (Soldering, 60 sec) 1 Rating 33 V -15 V to +14 V V1 Unlimited -65C to +150C -40C to +125C -65C to +125C 300C For supply voltages less than 36 V, the absolute maximum input voltage is equal to the supply voltage. Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; 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. THERMAL RESISTANCE JA is specified for the worst-case conditions, that is, a device soldered in the circuit board for the surface-mount packages. Table 4. Thermal Resistance Package Type 8-Lead SOIC 14-Lead SOIC ESD CAUTION Rev. C | Page 6 of 20 JA 158 120 JC 43 36 Unit C/W C/W OP292/OP492 TYPICAL PERFORMANCE CHARACTERISTICS 160 200 VS = 5V VCM = 0V TA = 25C 720 OP AMPS 175 150 120 100 60 50 40 25 20 0 -500 -400 -300 -200 -100 0 100 200 300 INPUT OFFSET VOLTAGE, VOS (V) 400 0 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 INPUT OFFSET VOLTAGE, VOS (mV) 500 Figure 3. OP292 Input Offset Voltage Distribution @ 5 V 0.5 0.6 00310-006 75 2.0 00310-007 80 5.0 00310-008 UNITS 100 00310-003 UNITS 125 Figure 6. OP492 Input Offset Voltage Distribution @ 5 V 240 320 VS = 15V VCM = 0V TA = 25C 720 OP AMPS 280 240 VS = 15V VCM = 0V TA = 25C 600 OP AMPS 200 160 UNITS 200 UNITS VS = 5V VCM = 0V TA = 25C 600 OP AMPS 140 160 120 120 80 80 40 0 00310-004 40 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 INPUT OFFSET VOLTAGE, VOS (mV) 1.8 0 2.0 0.8 1.0 1.2 1.4 1.6 1.8 VS = 5V VCM = 0V -40C TA +125C 600 OP AMPS 140 120 UNITS 100 80 80 60 60 40 40 20 20 00310-005 UNITS 0.6 160 VS = 5V VCM = 0V -40C TA +125C 600 OP AMPS 100 0 0.4 Figure 7. OP492 Input Offset Voltage Distribution @ 15 V 160 120 0.2 INPUT OFFSET VOLTAGE, VOS (mV) Figure 4. OP292 Input Offset Voltage Distribution @ 15 V 140 0 0 0.4 0.8 1.2 1.6 2.0 2.4 TCVOS (V/C) 2.8 3.2 3.6 0 4.0 Figure 5. OP292 Temperature Drift (TCVOS) Distribution @ 5 V 0 0.5 1.0 1.5 2.0 2.5 3.0 TCVOS (V/C) 3.5 4.0 4.5 Figure 8. OP492 Temperature Drift (TCVOS) Distribution @ 5 V Rev. C | Page 7 of 20 OP292/OP492 200 240 VS = 5V VCM = 0V -40C TA +125C 600 OP AMPS 210 180 150 120 100 90 75 60 50 30 25 0 0 1 2 3 4 5 TCVOS (V/C) 6 7 8 0 Figure 9. OP292 Temperature Drift (TCVOS) Distribution @ 15 V 0 1 2 3 4 5 TCVOS (V/C) 6 7 8 00310-012 UNITS 125 00310-009 UNITS 150 Figure 12. OP492 Temperature Drift (TCVOS) Distribution @ 15 V 900 600 OPEN-LOOP GAIN (V/mV) 700 400 300 RL = 10k 200 RL = 2k 100 VS = 5V VO = 4V 800 VS = 5V VO = 4V 500 OPEN-LOOP GAIN (V/mV) VS = 15V VCM = 0V -40C TA +125C 600 OP AMPS 175 RL = 10k 600 500 400 300 RL = 2k 200 0 25 50 75 100 125 TEMPERATURE (C) 0 -50 0 25 50 TEMPERATURE (C) 75 100 125 125 Figure 13. OP492 Open-Loop Gain vs. Temperature @ 5 V Figure 10. OP292 Open-Loop Gain vs. Temperature @ 5 V 400 250 VS = 15V VO = 10V VS = 15V VO = 10V 350 OPEN-LOOP GAIN (V/mV) 200 150 RL = 10k 100 RL = 2k 300 RL = 10k 250 200 150 RL = 2k 100 50 50 0 -50 -25 0 25 50 75 100 125 TEMPERATURE (C) 0 -50 00310-011 OPEN-LOOP GAIN (V/mV) -25 00310-013 -25 00310-010 0 -50 00310-014 100 -25 0 25 50 TEMPERATURE (C) 75 100 Figure 14. OP492 Open-Loop Gain vs. Temperature @ 15 V Figure 11. OP292 Open-Loop Gain vs. Temperature @ 15 V Rev. C | Page 8 of 20 OP292/OP492 1.2 VS = 15V 1.0 VS = +5V 0.8 0.6 0.4 0.2 -50 0 -25 25 50 TEMPERATURE (C) 75 100 125 VS = 15V 1.0 0.8 VS = +5V 0.6 0.4 0.2 -50 Figure 15. OP292 Supply Current per Amplifier vs. Temperature -25 0 25 50 TEMPERATURE (C) 75 100 125 Figure 18. OP492 Supply Current per Amplifier vs. Temperature 6 6 VS = 15V VO = 10V VS = 15V VO = 10V +SR 5 +SR 5 4 -SR SLEW RATE (V/s) SLEW RATE (V/s) 1.2 00310-018 SUPPLY CURRENT PER AMPLIFIER (mA) 1.4 00310-015 SUPPLY CURRENT PER AMPLIFIER (mA) 1.4 +SR 3 2 -SR 4 -SR 3 +SR 2 -SR 1 1 VS = 5V VO = 0.1V, 4V 25 50 TEMPERATURE (C) 75 100 125 0 -50 Figure 16. OP292 Slew Rate vs. Temperature 25 50 TEMPERATURE (C) 75 100 125 90 TA = 25C V+ = 5V V- = 0V RL = 10k 80 70 TA = 25C VS = 10k RL = 10k 80 70 60 60 PHASE 20 135 90 10 45 0 0 1k 10k 100k FREQUENCY (Hz) 1M -45 10M PHASE (Degrees) 30 PHASE MARGIN = 83 40 30 PHASE MARGIN = 92 PHASE +90 10 +45 0 0 Figure 17. OP292/OP492 Open-Loop Gain and Phase vs. Frequency @ 5 V +135 20 -10 1k 10k 100k FREQUENCY (Hz) 1M -45 10M PHASE (DEGREES) 40 GAIN 50 00310-020 50 GAIN (dB) GAIN 00310-017 GAIN (dB) 0 Figure 19. OP492 Slew Rate vs. Temperature 90 -10 -25 00310-019 0 -25 00310-016 0 -50 VS = 5V VO = 0.1V, 4V Figure 20. OP292/OP492 Open-Loop Gain and Phase vs. Frequency @ 15 V Rev. C | Page 9 of 20 OP292/OP492 50 50 TA = 25C V+ = 5V V- = 0V 30 20 10 20 10 0 10k 100k 1M 10M -10 00310-021 1k FREQUENCY (Hz) 1k 100k 1M 10M Figure 24. OP292/OP492 Closed-Loop Gain vs. Frequency @ 15 V 120 100 COMMON-MODE REJECTION (dB) TA = 25C V+ = 5V V- = 0V 80 60 40 20 1k 10k 100k 1M FREQUENCY (Hz) 80 60 40 20 0 100 00310-022 10k 100k 1M FREQUENCY (Hz) Figure 22. OP292/OP492 CMR vs. Frequency @ 5 V Figure 25. OP292/OP492 CMR vs. Frequency @ 15 V 120 120 POWER SUPPLY REJECTION (dB) TA = 25C VS = 5V 100 80 60 40 1k 10k 100k FREQUENCY (Hz) 1M 00310-023 20 0 100 1k Figure 23. OP292/OP492 PSR vs. Frequency @ 5 V TA = 25C VS = 15V 100 80 +PSSR 60 -PSSR 40 20 0 100 1k 10k 100k FREQUENCY (Hz) Figure 26. OP292/OP492 PSR vs. Frequency @ 15 V Rev. C | Page 10 of 20 1M 00310-026 0 100 TA = 25C VS = 15V 100 00310-025 120 POWER SUPPLY REJECTION (dB) 10k FREQUENCY (Hz) Figure 21. OP292/OP492 Closed-Loop Gain vs. Frequency @ 5 V COMMON-MODE REJECTION (dB) 30 00310-024 0 -10 TA = 25C VS = 15V 40 CLOSED-LOOP GAIN (dB) CLOSED-LOOP GAIN (dB) 40 OP292/OP492 4.4 OUTPUT SWING (V) RL = 100k 10.0 RL = 10k 4.2 RL = 2k 4.0 3.8 -50 -25 0 25 50 TEMPERATURE (C) 75 100 125 00310-027 OUTPUT VOLTAGE SWING (V) 4.6 14.0 -OUTPUT SWING (V) 15.0 VS = 5V Figure 27. OP292/OP492 VOUT Swing vs. Temperature @ 5 V VS = 15V RL = 100k RL = 10k 13.0 RL = 2k 12.0 11.0 RL = 2k -14.0 -14.5 RL = 10k RL = 100k -15.0 -50 0 -25 25 50 TEMPERATURE (C) 75 100 125 00310-030 4.8 Figure 30. OP292/OP492 VOUT Swing vs. Temperature @ 15 V 10 600 VS = 15V VCM = 0V VS = 5V VCM = 0V INPUT BIAS CURRENT (nA) INPUT BIAS CURRENT (A) 500 OP492 1 OP292 400 OP492 300 OP292 200 -25 0 25 50 TEMPERATURE (C) 75 100 125 0 -50 00310-028 0.1 -50 Figure 28. OP292/OP492 Input Bias Current vs. Temperature @ 5 V 25 50 TEMPERATURE (C) 75 100 125 Figure 31. OP292/OP492 Input Bias Current vs. Temperature @ 15 V -40 0.50 0.48 0.46 0.44 -60 IB CURRENT (nA) VS = +5V, 15V RL = 2k VO = 3V p-p -80 -90 -100 -RAIL +15V 0.42 0.40 0.38 0.36 A V 0.34 0.32 0.30 0.28 IN -15V 0.26 0.24 -110 +RAIL 0.22 -120 0 10 100 1k 10k FREQUENCY (Hz) 100k Figure 29. OP292/OP492 Channel Separation 0.18 0 1 2 3 4 5 6 7 8 VIN (V) 9 10 11 12 13 14 15 Figure 32. OP292/OP492 IB Current vs. Common-Mode Voltage Rev. C | Page 11 of 20 00310-032 0.20 00310-029 CHANNEL SEPARATION (dB) 0 -25 00310-031 100 CH A 800dV FS 0Hz MKR: 1000Hz 100dV/DIV MKR: 16.9V/Hz 25kHz BW: 150Hz 00310-033 OP292/OP492 Figure 33. Voltage Noise Density Rev. C | Page 12 of 20 OP292/OP492 APPLICATIONS INFORMATION PHASE REVERSAL 1V/DIV An input voltage that is as much as 5 V below the negative rail will not result in phase reversal. 11.8V p-p 10V p-p OP492 2k 4ms/DIV Figure 35. No Negative Rail Phase Reversal, Even with Input Signal at 5 V Below Ground The OP292/OP492 are designed to operate equally well at single +5 V or 15 V supplies. The lowest supply voltage recommended is 4.5 V. 100 90 It is a good design practice to bypass the supply pins with a 0.1 F ceramic capacitor. It helps improve filtering of high frequency noise. OP492 2k 10 0% 5s Figure 34. Output Phase Reverse If Input Exceeds the Positive Supply (V+) by More Than 0.9 V 00310-034 0V 0V POWER SUPPLY CONSIDERATIONS 1V 5V 5V 00310-035 The OP492 has built-in protection against phase reversal when the input voltage goes to either supply rail. In fact, it is safe for the input to exceed either supply rail by up to 0.6 V with no risk of phase reversal. However, the input should not go beyond the positive supply rail by more than 0.9 V; otherwise, the output will reverse phase. If this condition occurs, the problem can be fixed by adding a 5 k current limiting resistor in series with the input pin. With this addition, the input can go to more than 5 V beyond the positive rail without phase reversal. For dual-supply operation, the negative supply (V-) must be applied at the same time, or before V+. If V+ is applied before V-, or in the case of a loss of the V- supply, while either input is connected to ground or another low impedance source, excessive input current may result. Potentially damaging levels of input current can destroy the amplifier. If this condition can exist, simply add a l k or larger resistor in series with the input to eliminate the problem. Rev. C | Page 13 of 20 OP292/OP492 TYPICAL APPLICATIONS Figure 36 shows a 5 V single-supply transmit/receive telephone line interface for a modem circuit. It allows full duplex transmission of modem signals on a transformer-coupled 600 V line in a differential manner. The transmit section gain can be set for the specific modem device output. Similarly, the receive amplifier gain can be appropriately selected based on the modem device input requirements. The circuit operates on a single 5 V supply. The standard value resistors allow the use of a SIP-packaged resistor array; coupled with a quad op amp in a single package, this offers a compact, low part count solution. TX GAIN ADJUST 50k 1:1 20k 0.1F 300k 1/4 OP492 300k TRANSMIT TXA 20k T1 20k 6.2V 6.2V MODEM 5k 10F 20k 5V 20k 1/4 OP492 RX GAIN ADJUST 20k 50k 0.1F RECEIVE RXA 00310-036 0.1F VREF 20k VOUT 4 1 5k 5k 20k VOUT = 5 + RG 40k RG + VREF Figure 37. Single-Supply Instrumentation Amplifier In this configuration, the output can swing to near 0 V; however, be careful because the common-mode voltage range of the input cannot operate to 0 V. This is because of the limitation of the circuit configuration where the first amplifier must be able to swing below ground to attain a 0 V common-mode voltage, which it cannot do. Depending on the gain of the instrumentation amplifier, the input common-mode extends to within about 0.3 V of zero. The worst-case common-mode limit for a given gain can be easily calculated. The OP292/OP492 are ideal for buffering the output of singlesupply DACs. Figure 38 shows a typical amplifier used to buffer the output of a CMOS DAC that is connected for single-supply operation. To do that, the normally current output 12-bit CMOS DAC (R-2R ladder type) is connected backward to produce a voltage output. This operating configuration necessitates a low voltage reference. In this case, a 1.235 V low power reference is used. The relatively high output impedance (10 k) is buffered by the OP292, and at the same time, gained up to a much more usable level. The potentiometer provides an accurate gain trim for a 4.095 V full-scale, allowing 1 mV increment per LSB of control resolution. 5V DC 20k 1/2 OP292 7 DAC OUTPUT AMPLIFIER 1/4 OP492 100pF 5k 8 1/2 OP292 VIN 20k Figure 36. Universal Direct Access Arrangement for Telephone Line Interface The DAC8043 device comes in an 8-lead PDIP package, providing a cost-effective, compact solution to a 12-bit analog channel. 5V SINGLE-SUPPLY INSTRUMENTATION AMPLIFIER A low cost, single-supply instrumentation amplifier can be built as shown in Figure 37. The circuit uses two op amps to form a high input impedance differential amplifier. Gain can be set by selecting resistor RG, which can be calculated using the transfer function equation. Normally, VREF is set to 0 V. Then the output voltage is a function of the gain times the differential input voltage. However, the output can be offset by setting VREF from 0 V to 4 V, as long as the input common-mode voltage of the amplifier is not exceeded. 1/2 OP292 5V 5V 7.5k NC 1.235V AD589 DAC8043 VDD 1 VREF DD 8 2 RFB Clk 7 CLK 3 IOUT Sri 6 SRI 4 GND LD VOUT 1mV/LSB 0V - 4.095V FS 20k 8.45k 5 500k LD SRI CLK DIGITAL CONTROL Figure 38. 12-Bit Single-Supply DAC with Serial Bus Control Rev. C | Page 14 of 20 00310-038 TO TELEPHONE LINE 5V 5 00310-037 DIRECT ACCESS ARRANGEMENT FOR TELEPHONE LINE INTERFACE OP292/OP492 The amount of rejection and the Q of the filter is solely determined by one resistor and is shown in the table with Figure 39. The bottom amplifier is used to split the supply to bias the amplifier to midlevel. The circuit can be modified to reject 50 Hz by simply changing the resistors in the twin-T section (Rl through R4) from 2.67 k to 3.16 k and by changing R5 to 1/2 of 3.16 k. For best results, the common value resistors can be from a resistor array for optimum matching characteristics. R2 2.67k VIN R1 2.67k 1/4 OP492 R6 100k 12V 1/4 OP492 C3 2F (1F x 2) VOUT R5 1.335k (2.67k / 2) R7 1k RQ + C4 1F 40 1.33 2.0 35 1.50 1.25 3.0 30 1.60 2.50 8.0 25 1.80 5.00 18 20 1.90 10.00 38 15 1.95 NOTES 1. FOR 50Hz APPLICATION CHANGE R12 TO R4 TO 3.16k AND R5 TO 1.58k (3.16k / 2) VIN 3 5 1/2 OP292 7 VOUT 1.1k 14.3k 4 100F 1.78k 16.2k 5k 1 1/2 OP292 2200pF 3300pF Figure 40. Four-Pole Bessel Low-Pass Filter Using Sallen-Key Topology LOW COST, LINEARIZED THERMISTOR AMPLIFIER An inexpensive thermometer amplifier circuit can be implemented using low cost thermistors. One such implementation is shown in Figure 41. The circuit measures temperature over the range of 0C to 70C to an accuracy of 0.3C as the linearization circuit works well within a narrow temperature range. However, it can measure higher temperatures but at a slightly reduced accuracy. To achieve the aforementioned accuracy, the nonlinearity of the thermistor must be corrected. This is done by connecting the thermistor in parallel with the 10 k in the feedback loop of the first stage amplifier. A constant operating current of 281 A is supplied by the resistor R1 with the 5 V reference from the REF195 such that the self-heating error of the thermistor is kept below 0.1C. RT1 10k NTC 15V 00310-039 1.0 1.00 0.01F 0.022F To calibrate, a precision decade box can be used in place of the thermistor. For 0C trim, the decade box is set to 32.650 k, and P1 is adjusted until the output of the circuit reads 0 V. To trim the circuit at the full-scale temperature of 70C, the decade box is then set to 1.752 k, and P2 is adjusted until the circuit reads -0.70 V. FILTER Q RQ (k ) REJECTION (dB) VOLTAGE GAIN 0.75 5k 6 8 This linearization network creates an offset voltage that is corrected by summing a compensating current with Potentiometer P1. The temperature dependent signal is amplified by the second stage, producing a transfer coefficient of -10 mV/C at the output. 8k 6V 1/4 OP492 2 In many cases, the thermistor is placed some distance from the signal conditioning circuit. Under this condition, a 0.1 F capacitor placed across R2 will help to suppress noise pickup. R4 2.67k R3 2.67k 12V R8 100k R9 100k C2 1F C1 1F 5V 5V Figure 39 shows a notch filter that achieves nearly 30 dB of 60 Hz rejection while powered by only a single 12 V supply. The circuit also works well on 5 V systems. The filter uses a twin-T configuration, whose frequency selectivity depends heavily on the relative matching of the capacitors and resistors in the twin-T section. Mylar is a good choice for the capacitors of the twin-T, and the relative matching of the capacitors and resistors determines the pass-band symmetry of the filter. Using 1% resistors and 5% capacitors produces satisfactory results. 00310-040 50 Hz/60 Hz SINGLE-SUPPLY NOTCH FILTER 1.0F R12 17.8k REF195 1F Figure 39. Single-Supply 50 Hz/60 Hz Notch Filter R12 17.8k 1/2 OP292 R3 10k R6 7.87k P2 200 70C TRIM 5V The linear phase filter in Figure 40 is designed to roll off at a voice-band cutoff frequency of 3.6 kHz. The four poles are formed by two cascading stages of 2-pole Sallen-Key filters. P1 10k 0C TRIM 1/2 OP292 R5 806k 1R = ALPHA THERMISTOR 13A1002-C3. T 2R1 = 0.1% IMPERIAL ASTRONICS M015. NOTES 1. ALL RESISTORS ARE 1%, 25ppm/C EXCEPT R5 = 1%, 100ppm/C. Figure 41. Low Cost Linearized Thermistor Amplifier Rev. C | Page 15 of 20 VOUT -10mV/C 00310-041 R4 41.2k FOUR-POLE BESSEL LOW-PASS FILTER OP292/OP492 SINGLE-SUPPLY ULTRASONIC CLAMPING/LIMITING RECEIVER AMPLIFIER PRECISION SINGLE-SUPPLY VOLTAGE COMPARATOR Figure 42 shows an ultrasonic receiver amplifier using the nonlinear impedance of low cost diodes to effectively control the gain for wide dynamic range. This circuit amplifies a 40 kHz ultrasonic signal through a pair of low cost clamping amplifiers before feeding a band-pass filter to extract a clean 40 kHz signal for processing. The OP292/OP492 have excellent overload recovery characteristics, making them suitable for precision comparator applications. Figure 43 shows the saturation recovery characteristics of the OP492. The amplifier exhibits very little propagation delay. The amplifier compares a signal to precisely <0.5 mV offset error. The signal is ac-coupled into the false-ground bias node by virtue of the capacitive piezoelectric sensing element. Rather than using an amplifier to generate a supply splitting bias, the false ground voltage is generated by a low cost resistive voltage divider. 1k 3V p-p OP492 2k -15V 10 0% 20k 5V PROGRAMMABLE PRECISION WINDOW COMPARATOR The OP292/OP492 can be used for precise level detection, such as in test equipment where a signal is measured within a range (see Figure 44). A pair of 12-bit DACs sets the threshold voltage level. The DACs have serial interface, which minimizes interconnection requirements. The DAC8512 has a control resolution of 1 mV/bit. Therefore, for 5 V supply operation, the maximum DAC output is 4.095 V. However, the OP292 accepts a maximum input of 4.0 V. 5V 68pF 12V 1M 1/4 OP492 1/4 OP492 5V 1 7.5V 56.2k 14k CS 68pF 1/4 OP492 PANASONIC EFR-RTB40K2 5s Figure 43. OP492 Has Fast Overload Recovery for Comparator Applications 12V RECEIVER 00310-043 2.21k The overall circuit has a gain range from -2 to -400, where the inversion comes from the band-pass filter stage. Operating with a Q of 5, the filter restores a clean, undistorted signal to the output. The circuit also works well with 5 V supply systems. 12V 100 90 +5V Each amplifier stage provides ac gain while passing on the dc self-bias. As long as the output signal at each stage is less than the forward voltage of a diode, each amplifier has unrestricted gain to amplify low level signals. However, as the signal strength increases, the feedback diodes begin to conduct, shunting the feedback current, and thus reducing the gain. Although distorting the waveform, the diodes effectively maintain a relatively constant amplitude even with large signals that otherwise would saturate the amplifier. In addition, this design is considerably more stable than the feedback type AGC. 600k 1V VOUT 12V 2 DECODE CLK 3 SDI 4 DAC8512 REF 8 3 DAC 7 2 8 1/2 OP292 4 CONTROL 1 HIGH 6 5 600k 0.01F 100k 10k 0.01F LD 7.5V 6.04k 1F CLR 1M 0.01F 5V 00310-042 10k DAC8512 1 REF 8 2 Figure 42. 40 kHz Ultrasonic Clamping/Limiting Receiver Amplifier 3 4 6 DAC 7 CONTROL 5 1/2 OP292 LOW 6 5 ANALOG INPUT Figure 44. Programmable Window Comparator with 12-Bit Threshold Level Control Rev. C | Page 16 of 20 7 00310-044 390k OP292/OP492 OUTLINE DIMENSIONS 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) 6.20 (0.2441) 5.80 (0.2284) 1.75 (0.0688) 1.35 (0.0532) 0.51 (0.0201) 0.31 (0.0122) COPLANARITY 0.10 SEATING PLANE 0.50 (0.0196) 0.25 (0.0099) 45 8 0 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) COMPLIANT TO JEDEC STANDARDS MS-012-A A 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. 012407-A 4.00 (0.1574) 3.80 (0.1497) Figure 45. 8-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-8) Dimensions shown in millimeters and (inches) 8.75 (0.3445) 8.55 (0.3366) 8 14 1 7 1.27 (0.0500) BSC 0.25 (0.0098) 0.10 (0.0039) COPLANARITY 0.10 0.51 (0.0201) 0.31 (0.0122) 6.20 (0.2441) 5.80 (0.2283) 0.50 (0.0197) 0.25 (0.0098) 1.75 (0.0689) 1.35 (0.0531) SEATING PLANE 45 8 0 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) COMPLIANT TO JEDEC STANDARDS MS-012-AB 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. 060606-A 4.00 (0.1575) 3.80 (0.1496) Figure 46. 14-Lead Standard Small Outline Package [SOIC_N] Narrow Body (R-14) Dimensions shown in millimeters and (inches) ORDERING GUIDE Model OP292GS OP292GS-REEL OP292GSZ 1 OP292GSZ-REEL1 OP492GS OP492GS-REEL OP492GSZ1 OP492GSZ-REEL1 1 Temperature Range -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C Package Description 8-Lead Narrow Body SOIC_N 8-Lead Narrow Body SOIC_N 8-Lead Narrow Body SOIC_N 8-Lead Narrow Body SOIC_N 14-Lead Narrow Body SOIC_N 14-Lead Narrow Body SOIC_N 14-Lead Narrow Body SOIC_N 14-Lead Narrow Body SOIC_N Z = RoHS Compliant Part. Rev. C | Page 17 of 20 Package Option R-8 R-8 R-8 R-8 R-14 R-14 R-14 R-14 OP292/OP492 NOTES Rev. C | Page 18 of 20 OP292/OP492 NOTES Rev. C | Page 19 of 20 OP292/OP492 NOTES (c)1993-2009 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D00310-0-5/09(C) Rev. C | Page 20 of 20