Thermal Noise Analysis of a Programmable-Gain Switched-Capacitor Amplifier With Input Offset Cancellation

In this brief, we analyze the thermal noise in a switched-capacitor (SC) amplifier with input offset cancellation. We quantify the increase in thermal noise due to the extra phase required for offset sampling. We show that this noise penalty increases with the SC amplifier gain. A closed-form expression is obtained for the output RMS noise voltage for the special case where the amplifier is designed for low-power applications. Results obtained using our model match well with SPICE simulations.