Analysis and simulation of the effects of parametric drift on amplifiers

From the varying threshold voltage of MOSFET caused by the external factor, this paper analyzes the variation tendency of amplifier's gain. It makes clear how the gain of three different amplifiers changes in theoretical. After that, EDA tools are utilized to verify the theoretical calculation. The theoretical and simulation result show that threshold voltage(Vth) is a sensitive parameter of amplifier's gain. In a specific range, the gain of amplifier will becomes smaller and smaller with the decreasing Vth of input transistor.