Analysis and Simulation Study on the Impact of MOSFET Second-Order Effects on Common-Source Amplifier Performance

This paper analyzes the generation mechanism of channel length modulation and body effect from the perspective of device physics, as well as their impact on key parameters. Subsequently, using the Cadence Spectre simulation platform and the controllable variable method, the characteristic curve was extracted at the device level. At the circuit level, the influence mode of these second-order effects on voltage gain and static working points is studied. Finally, the co-source co-grid configuration is introduced to verify its effectiveness in reducing the channel length modulation effect. With the decrease in the channel length, the output resistance decreases significantly, resulting in a decrease in the voltage gain of the common source amplifier. The body effect will increase the threshold voltage and reduce the on resistance, thus further reducing the circuit gain and destroying the bias stability. The cascade structure effectively improves the equivalent output resistance, thus improving the voltage gain performance.