Mosfet as switch

Hi guys,

I"m having a little difficulty with using the mosfet as a switch. I want it to let trough to the negative input of a opamp ( inverting opamp mode).

VoDAC -------------mosfet -------------- R - opamp


The gate will be driven from a PIC (0 or 5V)and VoDAC will go from 0V to 2V. I tried the P channel enhanced mode with low gate threshold but when I higher the VoDAC ( gate is 5V), the source of the mosfet lowers negative...

Someone has any idea of a mosfet with low Vds and will work properly when I switch on the gate?

Kind regards

What you're doing is tricky to build that way. Try using an analog bilateral switch instead, like a 4066.