Effects of cryogenic temperatures on small-signal MOSFET capacitances

Many analog electronics, such as the front-end circuitry of audio, video and radio frequency amplifiers and active filters, involve small signal transistor operation. Under small signal operation, a DC bias or quiescent point is first established for the circuit. Then a small AC signal is applied, giving rise to a small variation about the operating point. The main idea behind small signal operation is that this variation is sufficiently small to assume a linear response of the electronics.