Design of a Negative Signal Handing Analog Switch

An analog switching circuit with low on-resistance flatness, low crosstalk, high bandwidth and high isolation applied to audio signal transmission system is presented. The proposed switch model is CMOS, which is composed of 5VPMOS and 5V isolated NMOS in parallel. 0.18 umBCD process is adopted. Simulation results show that Ron is 0.28Ω when the input signal is in the voltage range of −2~ 5V. The off isolation at 100kHz frequency is −82.35dB, and the bandwidth is higher at 87MHz, and the high-frequency performance is good.