G = 50, CMOS Sensor Amplifier with Current Excitation AD8290 FEATURES GENERAL DESCRIPTION Supply voltage range: 2.6 V to 5.5 V The AD8290 contains both an adjustable current source to Low power drive a sensor and a difference amplifier to amplify the signal 1.2 mA + 2 excitation current voltage. The amplifier is set for a fixed gain of 50. The AD8290 0.5 A shutdown current is an excellent solution for both the drive and the sensing aspects Low input bias current: 100 pA required for pressure, temperature, and strain gage bridges. High CMRR: 120 dB In addition, because the AD8290 operates with low power, Space savings: 16-lead, 3.0 mm 3.0 mm 0.55 mm LFCSP works with a range of low supply voltages, and is available in a Excitation current low profile package, it is suitable for drive/sense circuits in 300 A to 1300 A range portable electronics as well. Set with external resistor The AD8290 is available in a lead free 3.0 mm 3.0 mm 0.55 mm package and is operational over the industrial APPLICATIONS temperature range of 40C to +85C. Bridge and sensor drives Portable electronics FUNCTIONAL BLOCK DIAGRAM C FILTER ENBL R SET 11 6 5 3 V CC 2 13 10 GND 15 C BRIDGE 4 ADC ANTI- ALIASING 14 AD8290 FILTER V REF NC NC NC NC NC NC 1 7 8 9 12 16 Figure 1. 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 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 20072008 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 06745-001AD8290 TABLE OF CONTENTS Features .............................................................................................. 1 Current Source............................................................................ 15 Applications....................................................................................... 1 Applications Information .............................................................. 16 General Description ......................................................................... 1 Typical Connections .................................................................. 16 Functional Block Diagram .............................................................. 1 Current Excitation...................................................................... 16 Revision History ............................................................................... 2 Enable/Disable Function........................................................... 16 Specifications..................................................................................... 3 Output Filtering.......................................................................... 16 Absolute Maximum Ratings............................................................ 5 Clock Feedthrough..................................................................... 16 Thermal Resistance ...................................................................... 5 Maximizing Performance Through Proper Layout............... 17 ESD Caution.................................................................................. 5 Power Supply Bypassing............................................................ 17 Pin Configuration and Function Descriptions............................. 6 Dual-Supply Operation ............................................................. 17 Typical Performance Characteristics ............................................. 7 Pressure Sensor Bridge Application......................................... 18 Theory of Operation ...................................................................... 14 Temperature Sensor Application.............................................. 19 Amplifier...................................................................................... 14 ADC/Microcontroller................................................................ 19 High Power Supply Rejection (PSR) and Common-Mode Outline Dimensions ....................................................................... 20 Rejection (CMR) ........................................................................ 14 Ordering Guide .......................................................................... 20 1/f Noise Correction .................................................................. 14 REVISION HISTORY 2/08Rev. SpA to Rev. B Changes to Features Section............................................................ 1 Changes to Amplifier Section and Figure 43 .............................. 14 Changes to Current Source Section ............................................. 15 Changes to Current Excitation Section, Output Filtering Section, Clock Feedthrough Section, and Figure 45.................. 16 Changes to Figure 46...................................................................... 17 8/07Revision SpA 7/07Revision 0: Initial Version Rev. B Page 2 of 20