Zero Drift, Digitally Programmable Instrumentation Amplifier Data Sheet AD8231 FEATURES FUNCTIONAL BLOCK DIAGRAM Digitally/pin-programmable gain G = 1, 2, 4, 8, 16, 32, 64, or 128 Specified from 40C to +125C 1 12 50 nV/C maximum input offset drift NC +V S 10 ppm/C maximum gain drift LOGIC 2 11 INA V S Excellent dc performance IN-AMP 80 dB minimum CMR, G = 1 3 10 +INA OUTA 15 V maximum input offset voltage 4 9 500 pA maximum bias current NC REF OP 0.7 V p-p noise (0.1 Hz to 10 Hz) AMP AD8231 Good ac performance 2.7 MHz bandwidth, G = 1 1.1 V/s slew rate Rail-to-rail output Figure 1. Shutdown/multiplex Extra op amp Table 1. Instrumentation and Difference Amplifiers by Single-supply range: 3 V to 5 V Category Dual-supply range: 1.5 V to 2.5 V High Low High Mil Low Digital Qualified for automotive applications Performance Cost Voltage Grade Power Gain 1 1 1 AD8221 AD623 AD628 AD620 AD627 AD8231 APPLICATIONS 1 1 AD8220 AD8553 AD629 AD621 AD8250 Pressure and strain transducers AD8222 AD524 AD8251 1 1 Thermocouples and RTDs AD8224 AD526 AD8555 1 Programmable instrumentation AD624 AD8556 1 AD8557 Industrial controls Weigh scales 1 Rail-to-rail output. Automotive controls GENERAL DESCRIPTION The AD8231 also includes an uncommitted op amp that can be The AD8231 is a low drift, rail-to-rail, instrumentation amplifier used for additional gain, differential signal driving, or filtering. with software-programmable gains of 1, 2, 4, 8, 16, 32, 64, or 128. Like the in-amp, the op amp has an auto-zero architecture, rail- The gains are programmed via digital logic or pin strapping. to-rail input, and rail-to-rail output. The AD8231 is ideal for applications that require precision The AD8231 includes a shutdown feature that reduces current performance over a wide temperature range, such as industrial to a maximum of 1 A. In shutdown, both amplifiers also have temperature sensing and data logging. Because the gain setting a high output impedance, which allows easy multiplexing of resistors are internal, maximum gain drift is only 10 ppm/C for multiple amplifiers without additional switches. gains of 1 to 32. Because of the auto-zero input stage, maximum input offset is 15 V and maximum input offset drift is just The AD8231 is specified over the extended industrial tempera- 50 nV/C. CMRR is 80 dB for G = 1, increasing to 110 dB at ture range of 40C to +125C. It is available in a 4 mm 4 mm higher gains. 16-lead LFCSP. Rev. E 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 20072017 Analog Devices, Inc. All rights reserved. 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. Technical Support www.analog.com 5 16 SDN A2 6 15 +INB A1 7 14 INB A0 8 13 OUTB CS 06586-001AD8231 Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Gain Selection ............................................................................. 18 Applications ....................................................................................... 1 Reference Terminal .................................................................... 18 Functional Block Diagram .............................................................. 1 Layout .......................................................................................... 19 General Description ......................................................................... 1 Input Bias Current Return Path ............................................... 19 Revision History ............................................................................... 2 Input Protection ......................................................................... 19 Specifications ..................................................................................... 3 RF Interference ........................................................................... 20 Absolute Maximum Ratings ............................................................ 7 Common-Mode Input Voltage Range ..................................... 20 Thermal Resistance ...................................................................... 7 Reducing Noise ........................................................................... 20 Maximum Power Dissipation ..................................................... 7 Applications Information .............................................................. 21 ESD Caution .................................................................................. 7 Differential Output .................................................................... 21 Pin Configuration and Function Descriptions ............................. 8 Multiplexing ................................................................................ 21 Typical Performance Characteristics ............................................. 9 Using the AD8231 with Bipolar Supplies ................................ 21 Instrumentation Amplifier Performance Curves ..................... 9 Sallen Key Filter .......................................................................... 22 Operational Amplifier Performance Curves .......................... 15 Outline Dimensions ....................................................................... 23 Performance Curves Valid for Both Amplifiers ..................... 17 Ordering Guide .......................................................................... 23 Theory of Operation ...................................................................... 18 Automotive Products ................................................................. 23 Amplifier Architecture .............................................................. 18 REVISION HISTORY 10/2017Rev. D to Rev. E Inserted Figure 9 Renumbered Sequentially.............................. 10 Inserted Figure 16, and Figure 18 to Figure 20 Renumbered Changed CP-16-17 to CP-16-23 .................................. Throughout Updated Outline Dimensions ....................................................... 23 Sequentially ..................................................................................... 11 Changes to Ordering Guide .......................................................... 23 Inserted Figure 24 Renumbered Sequentially ........................... 12 Deleted Figure 28 and Figure 29 Renumbered Sequentially ... 13 3/2017Rev. C to Rev. D Inserted Figure 33 and Figure 34 Renumbered Sequentially .. 14 Updated Outline Dimensions ....................................................... 23 Inserted Figure 41 to Figure 46 Renumbered Sequentially ..... 16 Changes to Ordering Guide .......................................................... 23 Inserted Figure 48 Renumbered Sequentially ........................... 17 Changes to Gain Selection Section and Figure 50 ..................... 18 Added Input Protection Section ................................................... 19 12/2014Rev. B to Rev. C Changes to Figure 12 to Figure 14 Captions ............................... 10 Added Reducing Noise Section .................................................... 20 Changes to Figure 19 and Figure 20 ............................................. 11 Changes to Multiplexing Section ................................................. 21 Updated Outline Dimensions ....................................................... 23 Added Using the AD8231 with Bipolar Supplies Section ......... 21 Changes to Ordering Guide .......................................................... 23 Added Sallen Key Filter Section ................................................... 22 Changes to Ordering Guide .......................................................... 23 4/2011Rev. A to Rev. B Changes to Features Section and Applications Section ............... 1 5/2007Revision 0: Initial Version Added Exposed Pad Notation to Outline Dimensions ............. 23 Changes to Ordering Guide .......................................................... 23 Added Automotive Products Section........................................... 23 9/2007Rev. 0 to Rev. A Changes to Features and General Description ............................. 1 Changes to Table 2 ............................................................................ 3 Changes to Table 3 ............................................................................ 5 Changes to Typical Performance Characteristics Layout ............ 9 Inserted Figure 3 to Figure 8 Renumbered Sequentially ............ 9 Rev. E Page 2 of 24