To my understanding a stable solution for a transistors is when the voltage will not fluctuate due to to a change in Vin or something like that. My question I guess would be, where would I start analyzing this circuit?

device parameters: kn = 1 mA/V^2, Vtn = 1V, R =1Kohm cross-coupled inverter

  • \$\begingroup\$ I seem to be missing something more to this problem. I can only find one possible answer. 1.127 \$\endgroup\$ – VanyaS Dec 15 '14 at 9:20
  • \$\begingroup\$ can anyone shed some light as to how to find the others? \$\endgroup\$ – VanyaS Dec 15 '14 at 9:20

Hint: This is a cross-coupled circuit that would typically have two stable states.

Start by assuming one (pick one) of the two transistors is in cutoff region and see if you can prove that the region the other MOSFET is operating in is consistent with that assumption.

  • \$\begingroup\$ So, what I did is I assumed transistor 2 is in cut-off mode and found that transistor 1 is in triode mode and I find that Vo1 is approximately 1.127. Now because I am looking for a stable solution and one of the transistors is off, that would be one of the stable solutions right? and the other can be found by making the same assumption, but on opposites transistors? \$\endgroup\$ – VanyaS Dec 15 '14 at 7:17
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    \$\begingroup\$ Be cautious with the term "stable". There are different meanings/explanations/definitions. It can mean (a) stable dc operating point, (b) dynamic stability (against unwanted oscillations), (c) stable oscillations (at a fixed frequency/repetition rate). \$\endgroup\$ – LvW Jan 15 '15 at 8:25

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