# BJT Op-Amp and Feedback Transfer Function

Discussion in 'Homework Help' started by tquiva, Nov 14, 2012.

1. ### tquiva Thread Starter Member

Oct 19, 2010
176
1

I am given the circuit in the following image:

All the BJT transistors, Q1-Q5 are contained within a single CA3096 chip and the output buffer stage is simply a 741 op-amp configured in its unity-gain mode.

It is assumed that:
1) $_{}V$BE-on = 0.7 V for all transistors
2) The 741 is an ideal op-amp
3) The dd value of $_{}V$C5 = 0 V

Given the above specs, I know that the transfer function is
A(s) =$\frac{wt}{s}$
and $_{w}$t = $\frac{gm}{Cpi + Cmu}$

My question is, do I have the correct approach in obtaining the transfer function? That I need to find for Cpi + Cmu in order to find wt? Or is there another method in doing this?

Also, does anyone know how I would find the slew rate (SR) for this circuit? I know that SR = $\frac{voltage change}{time change}$
But how would I find Δt?

Any help is greatly greatly appreciated! Thank you.

• ###### Screen Shot 2012-11-13 at 8.22.56 PM.png
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Last edited: Nov 14, 2012