0
\$\begingroup\$

I have a circuit, which is given below.

Cross coupled Differential amplifier

Now I want to find the time constant of the circuit, considering there are equal caps placed at node X and Y. For a small signal model I can easily find the time constant while the circuit is in small signal domain. However, since this is a latch circuit the feedback is positive so I assumed that all transistors get out of small signal domain; it enters into large signal domain (assuming all the transistors are in saturation), so I apply the large signal model of MOSFETs in saturation -- but in this stage how should I find the time constant?

What is the transfer function of $$\frac{V_\text{in1}-V_\text{in2}}{V_x-V_y}$$ where the function is independent of \$V_y\$ and \$V_x\$? When I am solving, I am getting the dependence of \$V_x\$ and \$V_y\$ in the transfer function.

\$\endgroup\$
4
  • \$\begingroup\$ Get hold of a free simulator and find out for yourself <-- it'll give you a far more accurate picture of things than a bunch of assumptions leading to an unsatisfactory formula. \$\endgroup\$
    – Andy aka
    Commented Sep 28, 2023 at 7:54
  • \$\begingroup\$ I already know the simulation part but simulation, don't tell much about the circuit nor does it tells how can i optimize it even if i get a rough idea it will help me in optimization \$\endgroup\$
    – thehappywine
    Commented Sep 28, 2023 at 9:15
  • \$\begingroup\$ You asked to find the time constant of the circuit. You didn't say you were having trouble understanding the circuit's operation or, you needed to optimize the circuit. Help can only be given on questions you raise. \$\endgroup\$
    – Andy aka
    Commented Sep 28, 2023 at 9:51
  • \$\begingroup\$ This sounds like a homework question; what background/supporting information have you seen so far (lectures, textbook, etc.), and what work have you done so far? (I'm not familiar with academic microelectronics curricula, but finding a time constant sounds like something academics would be interested in. My guess is -gm*C, the time for a given imbalance X-Y to be amplified by e times. What that has to do with the transfer function, I don't know.) \$\endgroup\$
    – Tim Williams
    Commented Sep 28, 2023 at 13:06

0

Reset to default

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.