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Article: The right way to use instrumentation amplifiers: avoid common application problems when connecting real-world signals to instrumentation amplifiers.
- Article from:
- EDN
- Article date:
- September 15, 2005
- Author:
CopyrightCOPYRIGHT 2005 Reed Business Information, Inc. (US). This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Instrumentation amplifiers find wide use in real-world data acquisition. However, designers often incorrectly apply them. Specifically, although modern in amps have excellent CMR (common-mode rejection), designers must limit the total common-mode voltage, plus the signal voltage, to avoid saturating the amplifier's internal input buffers. Unfortunately, they often overlook this requirement.
Other common application problems result from driving the in-amp reference terminal with a high-impedance source, operating low-supply-voltage in-amp circuits at gains that are much too high, ac coupling in-amp inputs without providing a dc return path to ground, and using ...