Design of a Low On-Resistance Flatness Analog Switch

In order to solve the problem of non-linear distortion introduced by the unstable RON of traditional CMOS switches, an analog switch circuit is proposed for audio-visual data transmission system. The designed analog switch selects the T-Switch structure to ensure the high-frequency performance of the switch; the driver circuit takes the output voltage of the charge pump as the power supply voltage, and at the same time receives the intermediate node voltage of the T-type switch and outputs the gate drive signal of the power tube, so as to make the power tube have a stable gate source voltage. The circuit is simulated using 0.18 umBCD process, and the results show that the input signal is in the voltage range of 0~0.4 V, the RON (flat) is 0.02Ω, the shutdown isolation is −123.7dB at 100kHz frequency, and the −3dB bandwidth is 1.5GHz.