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Article: Chopper-stabilized amplifier cascade yields 160 to 10,240 programmable gain.
- Article from:
- EDN
- Article date:
- November 23, 2006
CopyrightCOPYRIGHT 2006 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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Jerome E Johnston, Cirrus Logic Corp, Austin, TX
Edited by Brad Thompson and Fran Granville
Certain medical and scientific instrumentation applications require amplification and measurement of microvolt-level signals. For example, accurately measuring the output of a thermopile-based micro-calorimeter demands an amplifier that achieves high gain and exhibits excellent thermal stability and low noise.
Figure 1 illustrates how combining two amplifiers yields a programmable-gain amplifier that provides selectable gains of 160 to 10,240. The circuit also offers typical offset voltage of 5 [micro]V, offset drift of 20 nV/[degrees]C, and ...