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

Summary This 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. An offset cancellation technique for complementary input amplifiers in unity gain buffer configuration that overcomes the variable offset and minimizes distortion is presented. The proposed technique is geared toward continuous time applications. Simulation results show up to 40 dB increase in spurious‐free dynamic range and up to 30 dB increase in signal‐to‐noise and distortion ratio. Buffering a continuous time modulator, the proposed technique matches the performance of chopping amplifier. Measurement results verify the technique, illustrating effective offset cancellation regardless of the input signal level.