Dual Low Bias Current Precision Operational Amplifier OP297 FEATURES PIN CONFIGURATION Low offset voltage: 50 V maximum 1 OUTA 8 V+ Low offset voltage drift: 0.6 V/C maximum 2 INA 7 OUTB A B Very low bias current: 100 pA maximum +INA 3 6 INB Very high open-loop gain: 2000 V/mV minimum 4 5 V +INB Low supply current (per amplifier): 625 A maximum Figure 1. Operates from 2 V to 20 V supplies High common-mode rejection: 120 dB minimum 60 APPLICATIONS V = 15V S V = 0V CM Strain gage and bridge amplifiers 40 High stability thermocouple amplifiers Instrumentation amplifiers 20 Photocurrent monitors I B High gain linearity amplifiers 0 Long-term integrators/filters I + B Sample-and-hold amplifiers 20 Peak detectors I OS Logarithmic amplifiers 40 Battery-powered systems 60 GENERAL DESCRIPTION 75 50 25 0 25 50 75 100 125 TEMPERATURE (C) The OP297 is the first dual op amp to pack precision perform- Figure 2. Low Bias Current over Temperature ance into the space saving, industry-standard 8-lead SOIC package. The combination of precision with low power and extremely low input bias current makes the dual OP297 useful 400 1200 UNITS T = 25C in a wide variety of applications. A V = 15V S V = 0V Precision performance of the OP297 includes very low offset CM 300 (less than 50 V) and low drift (less than 0.6 V/C). Open- loop gain exceeds 2000 V/mV, ensuring high linearity in every application. 200 Errors due to common-mode signals are eliminated by the common-mode rejection of over 120 dB, which minimizes offset voltage changes experienced in battery-powered systems. 100 The supply current of the OP297 is under 625 A. The OP297 uses a super-beta input stage with bias current cancellation to maintain picoamp bias currents at all tempera- 0 100 80 60 40 20 0 20 40 60 80 100 tures. This is in contrast to FET input op amps whose bias INPUT OFFSET VOLTAGE (V) currents start in the picoamp range at 25C, but double for Figure 3. Very Low Offset every 10C rise in temperature, to reach the nanoamp range Combining precision, low power, and low bias current, the above 85C. Input bias current of the OP297 is under 100 pA at OP297 is ideal for a number of applications, including instru- 25C and is under 450 pA over the military temperature range mentation amplifiers, log amplifiers, photodiode preamplifiers, per amplifier. This part can operate with supply voltages as low and long term integrators. For a single device, see the OP97 for as 2 V. a quad device, see the OP497. Rev. G 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 One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 2008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. INPUT CURRENT (pA) NUMBER OF UNITS 00300-001 00300-003 00300-002OP297 TABLE OF CONTENTS Features .............................................................................................. 1 AC Performance ............................................................................9 Applications ....................................................................................... 1 Guarding and Shielding ................................................................9 General Description ......................................................................... 1 Open-Loop Gain Linearity ....................................................... 10 Pin Configuration ............................................................................. 1 Application Circuits ....................................................................... 11 Revision History ............................................................................... 2 Precision Absolute Value Amplifier ......................................... 11 Specif icat ions ..................................................................................... 3 Precision Current Pump ............................................................ 11 Electrical Characteristics ............................................................. 3 Precision Positive Peak Detector .............................................. 11 Absolute Maximum Ratings ............................................................ 4 Simple Bridge Conditioning Amplifier ................................... 11 Thermal Resistance ...................................................................... 4 Nonlinear Circuits ...................................................................... 12 ESD Caution .................................................................................. 4 Outline Dimensions ....................................................................... 13 Typical Performance Characteristics ............................................. 5 Ordering Guide .......................................................................... 14 Applications Information ................................................................ 9 REVISION HISTORY 4/08Rev. F to Rev. G 10/02Rev. C to Rev. D Changes to Table 2 Conditions ....................................................... 3 Edits to Figure 16 ............................................................................... 6 Changes to Table 2 Power Supply Rejection Parameter .............. 3 Changes to Figure 5, Figure 6, Figure 7 ......................................... 5 10/02Rev. B to Rev. C Changes to Figure 16 ........................................................................ 6 Edits to Specifications ....................................................................... 2 Deleted Wafer Test Limits ................................................................ 3 Updated Outline Dimensions ....................................................... 13 Changes to Ordering Guide .......................................................... 14 Deleted Dice Characteristics ............................................................ 3 Deleted Absolute Maximum Ratings .............................................. 4 2/06Rev. E to Rev. F Edits to Ordering Guide ................................................................... 4 Updated Format .................................................................. Universal Updated Outline Dimensions ....................................................... 12 Changes to Features .......................................................................... 1 Deleted OP297 Spice Macro Model Section ................................. 9 Updated Outline Dimensions ....................................................... 13 Changes to Ordering Guide .......................................................... 14 7/03Rev. D to Rev. E Changes to TPCs 13 and 16 ............................................................ 4 Edits to Figures 12 and 14 ............................................................... 8 Changes to Nonlinear Circuits Section ......................................... 8 Rev. G Page 2 of 16