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
    Hello everyone. Could someone please help me with the following problem?

    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) _{}VBE-on = 0.7 V for all transistors
    2) The 741 is an ideal op-amp
    3) The dd value of _{}VC5 = 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.
    Last edited: Nov 14, 2012