As the picture shows in the file, It should be a source follower circuit but why the output voltage(37nV) is so small compared to the input voltage which is 1Vac?

 

Not knowing anything about the MOSFETs in the schematic I would say the most likely problem is that the gates are not biased beyond above Vth (gate threshold). To do that, just add some DC in series with your 1V P-P signal. Remember, since this does not have a negative power supply, it will not work with input voltages that go below ground.

You might also have to raise the 3.3V power supply to get it to work. Check the MOSFET datasheet.

 

Not knowing anything about the MOSFETs in the schematic I would say the most likely problem is that the gates are not biased beyond above Vth (gate threshold). To do that, just add some DC in series with your 1V P-P signal. Remember, since this does not have a negative power supply, it will not work with input voltages that go below ground.

You might also have to raise the 3.3V power supply to get it to work. Check the MOSFET datasheet.

Thanks for your help, that's really appreciated. I might have to learn about how to set the parameters for devices in Pspice, as a apprentice LOL