BJT analog circuit design

[GGGboat]

hello, i need to design analog circuit that has a transfer curve as seen in the following image using resistors, capacitors,voltage, and BJT (with beta value of 100).

the parameters are:

A=75

f1= 21Hz

f2=21 KHz

M1=40

M2=-20

the circuit also need to have input resistance of Rin= 60 kilo-ohm and output resistance of 51 kilo-ohm.

i think the circuit should have 3 stages, each connected with a capacitor, where the first stage is for achieving the required input resistance, the second for the required gain, and the third is for the required output resistance.

(the first and last stages might also add some gain but it will be considered in the second stage)

My question is how do I know which of the following modules should I use for each stage?

is my 3-stage even make sense? is it the right approach?

 

thank you!

 

[studiot]

Yes I would agree that you need a three stage circuit, call them stages 1, 2 and 3, since you have to provide defined input and output filter characteristics with the rolloffs.

 

So stage 1 for the input filter, stage 2 for the required gain, stage 3 for the output filter.

 

The turnover points are very low in frequency and within the reach of any conceivable BJT f_t so that will not be a problem and a beta of 100is pretty usual.

I can't see a voltage gain (that was A?) presenting any problems either with a single BJT in stage 2.

 

So what are your next thoughts?

 

Edit my next thought is that you haven't stated the input voltage level. with an output requirement of V_o = 75V_in this will constrain your configuration possibilities and power supply requirements. In the light of this it may be sense to combine stages 2 and 3, perhaps as a coupled bjt pair.

Edited June 16, 2015 by studiot