An offset cancellation technique of complementary input pair buffers for continuous time applications

Abstract

SummaryThis letter describes an offset cancellation technique for rail‐to‐rail complementary input pair operational amplifiers in unity gain loop configuration that overcomes the variable offset and minimizes distortion. The simulated buffer exhibits up to 40 dB increase in spurious‐free dynamic range and up to 30 dB increase in signal‐to‐noise and distortion ratio. When used to buffer a continuous time modulator, the performance matches that of chopping. Measurement results verify the technique, illustrating effective offset cancellation regardless of the input signal level. Copyright © 2016 John Wiley & Sons, Ltd.