High Performance, Low Power, Rail-to-Rail Precision Instrumentation Amplifier Data Sheet AD8422 FEATURES TYPICAL APPLICATION DIAGRAM Low power: 330 A maximum quiescent current +5V Rail-to-rail output +5V Low noise and distortion +IN 8 nV/Hz maximum input voltage noise at 1 kHz V = V = 0.5V TO 2.5V OUT FS R AD8422 G 0.15 V p-p RTI noise (G = 100) 15mV +5V REF 0.5 ppm nonlinearity with 2 k load (G = 1) IN 24.9k Excellent ac specifications +24V R = 301 G 1 G = 66.8V/V 80 dB minimum CMRR at 10 kHz (G = 1) 2.2 MHz bandwidth (G = 1) 10.7k High precision dc performance (AD8422BRZ) ADA4096-2 150 dB minimum CMRR (G = 1000) 1 OPTIONAL 0.04% maximum gain error (G = 1000) ZERO ADJUST 0.3 V/C maximum input offset drift Figure 1. Bridge Amplifier with Output Zero Adjust 0.5 nA maximum input bias current Wide supply range The wide input range and rail-to-rail output of the AD8422 4.6 V to 36 V single supply bring all of the benefits of a high performance in-amp to single- 2.3 V to 18 V dual supply supply applications. Whether using high or low supply voltages, Input overvoltage protection: 40 V from opposite supply the power savings make the AD8422 an excellent choice for Gain range: 1 to 1000 high channel count or power sensitive applications. Available in 8-lead LFCSP, 8-lead MSOP, and 8-lead SOIC N The AD8422 uses robust input protection that ensures reliability APPLICATIONS without sacrificing noise performance. The AD8422 has high Medical instrumentation ESD immunity, and the inputs are protected from continuous Industrial process controls voltages up to 40 V from the opposite supply rail. Strain gages Transducer interfaces A single resistor sets the gain from 1 to 1000. The reference pin Precision data acquisition systems can be used to apply a precise offset to the output voltage. Channel-isolated systems The AD8422 is specified from 40C to +85C for the 8-lead Portable instrumentation MSOP and the 8-lead SOIC N and from 40C to +125C for GENERAL DESCRIPTION the 8-lead LFCSP. The AD8422 is a high precision, low power, low noise, rail-to-rail 20 instrumentation amplifier that delivers the best performance R = 2k L 30 V = 10V OUT per unit microampere in the industry. The AD8422 processes 40 signals with ultralow distortion performance that is load 50 independent over its full output range. 60 70 The AD8422 is the third generation development of the industry- 80 G = 1000 standard AD620. The AD8422 employs new process technologies 90 and design techniques to achieve higher dynamic range and G = 100 100 lower errors than its predecessors, while consuming less than G = 10 110 one-third of the power. The AD8422 uses the high performance G = 1 120 pinout introduced by the AD8221. 130 Very low bias current makes the AD8422 error free with high 140 10 100 1k 5k source impedance, allowing multiple sensors to be multiplexed FREQUENCY (Hz) to the inputs. Low voltage noise and low current noise make the Figure 2. Total Harmonic Distortion vs. Frequency AD8422 an ideal choice for measuring a Wheatstone bridge. Rev. B Document Feedback 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 20132021 Analog Devices, Inc. All rights reserved. license is granted by implication or otherwise under any patent or patent rights of Analog Devices. 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Technical Support www.analog.com AMPLITUDE (dBc) 11197-102 11197-001AD8422 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation ...................................................................... 21 Applications ....................................................................................... 1 Architecture ................................................................................ 21 General Description ......................................................................... 1 Gain Selection ............................................................................. 21 Typical Application Diagram .......................................................... 1 Reference Terminal .................................................................... 22 Revision History ............................................................................... 2 Input Voltage Range ................................................................... 22 Specifications ..................................................................................... 3 Layout .......................................................................................... 22 SOIC N.......................................................................................... 3 Input Bias Current Return Path ............................................... 23 MSOP ............................................................................................. 5 Input Voltages Beyond the Supply Rails .................................. 23 LFCSP ............................................................................................. 7 RF Interference (RFI) ................................................................. 24 Absolute Maximum Ratings .......................................................... 10 Applications Information .............................................................. 25 Thermal Resistance .................................................................... 10 Precision Bridge Conditioning ................................................. 25 Electrostatic Discharge (ESD) Ratings .................................... 10 Process Control Analog Input .................................................. 25 ESD Caution ................................................................................ 10 Outline Dimensions ....................................................................... 26 Pin Configurations and Function Descriptions ......................... 11 Ordering Guide .......................................................................... 27 Typical Performance Characteristics ........................................... 12 REVISION HISTORY 4/2021Rev. A to Rev. B 1/2015Rev. 0 to Rev. A Added 8-Lead LFCSP ......................................................... Universal Changes to Features Section ............................................................ 1 Changes to Features Section and General Description Section . 1 Changes to SOIC Package Section and Table 1 ............................. 4 Deleted Connection Diagram, Figure 1 Renumbered Changes to MSOP Package Section and Table 2 ........................... 5 Sequentially ....................................................................................... 1 Changes to Supply Voltage Parameter and Added Typical Application Diagram, Figure 1 Renumbered ESD Parameter, Table 3 ..................................................................... 8 Sequentially ....................................................................................... 1 Deleted Figure 12 and Figure 15, Renumbered Sequentially ... 11 Changes to Figure 10 to Figure 15 ................................................ 11 Changes to Table 1 ............................................................................ 3 Changes to Table 2 ............................................................................ 5 Changes to Figure 16, Figure 18, and Figure 19 ......................... 12 Added LFCSP Section and Table 3 Renumbered Sequentially ........ 7 Changes to Figure 23 and Figure 24............................................. 13 Changes to Thermal Resistance Section and Table 5 ................ 10 Changes to Figure 31, Figure 32, and Figure 33 ......................... 14 Added Electrostatic Discharge (ESD) Ratings Section, ESD Changes to Figure 64 ...................................................................... 23 Ratings for AD8422 Section, and Table 6 .................................... 10 Added Figure 4 Renumbered Sequentially ................................ 11 5/2013Revision 0: Initial Version Changes to Table 7 .......................................................................... 11 Changes to Figure 32 ...................................................................... 16 Updated Outline Dimensions ....................................................... 26 Changes to Ordering Guide .......................................................... 27 Rev. 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