Hi all,
I am trying some DC simulations in Hspice. I have a PMOS whose source is connected to Vdd and at its gate there is a voltage(sweeped from 0 to Vdd). The output is to be from the source. I want to measure the current at the output. Since source is floating, I think I have to connect a dummy voltage source to measure the current. Am I right?
The transistor is actually acting as a pull-up transistor and hence the output is at source. Thanks.
Your output is drain of PMOS, right?
for PMOS, the output current related to drain's voltage, before measure Isd, your'd better specify a voltage to it's drain.
Of course, pMOSFET current depends on Vsg as well as on Vsd. You may connect a Vsd source between the source (VDD) and the drain of your transistor as shown in the picture below. In this scheme you may change the ground to VDD and tie the drain to the ground. Anyway, any voltage source is needed to indicate a current flowing through it.
a.