PMOS problem with VSS and VDD

Thread Starter


Joined Oct 27, 2007
I'm having a bit of trouble getting started on this problem. All specifics are in the attached pdf.

Conceptually, I imagine I am suppose to figure out the voltages and currents going into the FET. However, I'm uncertain on how to do that for a FET that does not run to ground. I've found circuit examples similar to this, but none with VSS and VDD running both into the Rs and Rd AND the Gate.

Am I missing something? I just went over BJTs and they had constants. Is this a simple matter of "plug and chug?" and I'm forgetting a constant?

At first look it seems simple. The drain current should be the current coming out of Rd. But when you take Vss/Rd, you get -5/4K=1.25mA, when the answer is 1.04 mA.

Can anyone spot what I am missing?