Supply Variation Simulation on LTSpice

Discussion in 'Homework Help' started by prietess, Mar 21, 2011.

  1. prietess

    Thread Starter New Member

    Nov 30, 2010
    Hi everyone,

    Anybody knows how to do supply variation simulation on LTSpice?
    Basically I got a homework due tomorrow on the sensitivity of different current mirrors with respect to supply voltage.

    I have the pmos current mirror circuits ready. But how to simulate it on LTSpice? I have been trying to read the tutorials on AC analysis, noise analysis, etc, but cannot still get the result.

    Anybody probably would be so kind as to guide me? Really need urgent help....
    I attach the LTSpice circuit snapshot to make it easier....
    Thank you for your kindness....
  2. Ron H

    AAC Fanatic!

    Apr 14, 2005
    Do a DC sweep. Name of source to sweep is Vdd. Select Linear sweep, and make the start and stop values and the increment whatever you need to make them. For example, if you sweep from 3.2V to 3.4V, with 1mV increment, you can get a nice plot of Id(M3) vs Vcc.
  3. Georacer


    Nov 25, 2009
    Or if you want to examine ripples in the voltage source, you could superimpose a sine wave on the DC source. Depends on what it is exactly you want to study.