Analysis and Design of a Chopped Current Mode Instrumentation Amplifier

This paper presents the design of a chopper stabilized current mode instrumentation amplifier and analyzes the performance limitations imposed by chopping technique in detail. The amplifier targets to be the read out circuitry of a high precision temperature sensor. Since the required bandwidth in this kind of applications is very low, nested chopping technique is used to provide continuous offset reduction and eliminate 1/f noise. The amplifier is designed in 0.18 μm CMOS process. The resulting input referred noise is 20 nV/√ Hz, the offset is 582 nV and the CMRR exceeds 110 dB. The power consumption of the total design is 420 μW.