A CMOS Based Balanced Differential Amplifier with MOS Loads

Abstract

The Balanced Differential Amplifiers play a most important role as basic building block in instrumentation amplifier circuit. One of the characteristic of a differential amplifier, the common mode rejection ratio (CMRR) is most important. The active load used for balanced differential amplifier is going to affect differential gain, thus CMRR of the circuit. The active load used can be a diode connected load or current source load. Though the differential gain is limited by nonlinearity of MOSFET, optimum differential gain can be obtained by combination of both active loads.