A very compact CMOS instrumentation amplifier with nearly rail-to-rail input common mode range

This paper presents a compact, fully-differential instrumentation amplifier with nearly rail-to-rail input common mode range. The amplifier, which is based on an original topology, embodies chopper modulation for offset and flicker noise reduction. The paper describes the experimental results obtained with a prototype designed with the UMC 0.18 mu m MM/RF CMOS process. The amplifier draws 42 mu A at a supply voltage of 1.8 V with an input noise voltage density of 75 nV/sqrt(Hz). Total amplifier area is 0.056 mm(2).