Diode Connected NMOS

Discussion in 'Homework Help' started by psycoadam, Nov 14, 2011.

  1. psycoadam

    Thread Starter New Member

    Oct 18, 2011
    The problem given states:

    Two diode connected NMOS transistors are connected in series.
    Calculate the current in the these devices if the voltage across the
    series connection is 5 V. Both substrate contacts are tied to ground.

    Device parameters: VTN = 0.75 V, mun*Cox = 2.5x10^1 uA/V2,
    W/L = 10/1, gamma = 0.5 V0.5.

    There are two things I am concerned with. After doing some searching I believe I have figured out what they are asking by two "diode connected NMOS". I want to make sure that the way I have drawn the schematic is the proper orientation of the circuit.

    secondly I read that the current through one of the NMOS
    I = .5*kn'(W/L)*(v-Vt)^2

    The problem states that 5V is across the series connection so is that Vo between the two fets or is that Vcc to ground? For some reason I am having a tough time with this problem. I feel that it is simpler than I am making it I just would appreciate some help onto the right track.
  2. psycoadam

    Thread Starter New Member

    Oct 18, 2011
    If anyone has any help, or intuition I would really appreciate it. I am still stuck on this problem. Thanks again.
  3. salil87

    New Member

    Nov 4, 2011
    I dont know the details about the configuration but your substrates are not connected to ground. They are shorted to source.