Transmission gate circuit, programmable gain amplifier, chip and electronic equipment

The transmission gate circuit comprises a first MOS transistor, a second MOS transistor, a first switch and a second switch, when the transmission gate circuit is switched on, the substrate of the first MOS transistor and the substrate of the second MOS transistor are connected with the second ends of the first MOS transistor and the second MOS transistor respectively, the threshold voltage of the first MOS transistor and the threshold voltage of the second MOS transistor are reduced, meanwhile, the overdrive voltage is increased, and the on-resistance of the transmission gate circuit is smaller; when the transmission gate circuit is disconnected, the substrate of the first MOS transistor is connected with a power supply, the substrate of the second MOS transistor is grounded, the threshold voltage of the first MOS transistor and the second MOS transistor is increased, the overdrive voltage is reduced, the turn-off resistance of the transmission gate circuit is larger, and the area of the transmission gate ci