Dynamic Offset Cancellation in Operational Amplifiers and Instrumentation Amplifiers

This paper gives an overview of techniques that achieve low-offset, low-noise, and high accuracy in CMOS operational amplifiers (OA or OpAmp) and instrumentation amplifiers (IA or InstAmp). Auto-zero and chopper techniques are used apart and in combination with each other. Frequency-compensation techniques are shown that obtain straight roll-of amplitude characteristics in the multi-path architectures of chopper stabilized amplifiers. Therefore, these amplifiers can be used in standard feedback networks. Offset voltages lower than 1 mu V can be achieved.