In-amp specifies differential output

摘要

Waltham, Mass. — Instrumentation amplifiers (in-amps) are specialized, precise-gain op amps with a challenging task: They take a low-level input signal, such as an EEG or strain gage, which is accompanied by a large amount of common-mode noise, and extract that signal. These amps increasingly have to provide differential-drive output to the next stage in the signal chain, typically an A/D converter. Such differential signals are preferred because they provide increased immunity to on-board and inter-IC common-mode noise—a consequence of nearby digital signals aggravated by the reduction in supply voltages. Differential signals also provide 6-dB greater dynamic range and signal-to-noise ratio—both critical specs— compared with single-ended operation.