What are the characteristics and advantages of an instrumentation amplifier?

An instrumentation amplifier (IA) is a precision differential amplifier optimized for sensor signal conditioning. Key characteristics: high input impedance (doesn't load sensor), high common-mode rejection ratio (CMRR >80 dB rejects noise common to both inputs), low offset and drift, low noise, and gain settable with single resistor. Three-op-amp topology is standard: two input buffers with adjustable gain and one difference amplifier. Applications include bridge sensor interfaces, biomedical signals, and any application requiring amplification of small differential signals in presence of common-mode interference.