Desired specifications of a differential amplifier?

[hannover90]

Hello all,

I am designing a differential amplifier.

I have read definitions about gain, gain bandwidth, slew rate, ICMR, OCMR and Phase Margin, but which value of these specifications are desired for a common differential amplifier? (For example: gain should be 60dB or 80 dB?)

Thanks for any help in advance.

 

[crutschow]

It depends upon the application.
What do you want the differential amp to do?

 

[hannover90]

It depends upon the application.
What do you want the differential amp to do?

Thanks for your reply.
I am designing a diff. amplifier only for understanding how it works, how I can improve its gain, ICMR etc, but I want to know for example, what is the desired gain or SR of a diff. amplifier?

 

[nitishn5]

Select some decent specifications. Also decide whether you want a single stage or multiple stages. Multiple stages would need some compensation and can get more difficult.

Perhaps...
60dB Gain,
10MHz Bandwidth,
ICMR of about 50% of your supply voltage, the actual numbers would depend on whether your amp is NMOS input or PMOS input.
OCMR of about 30% of your supply voltage.

A basic 5 transistor differential amplifier would be able to meet these specifications.

Start from there and then you can try tweaking the circuit to squeeze out more performance.

 

[hannover90]

Select some decent specifications. Also decide whether you want a single stage or multiple stages. Multiple stages would need some compensation and can get more difficult.

Perhaps...
60dB Gain,
10MHz Bandwidth,
ICMR of about 50% of your supply voltage, the actual numbers would depend on whether your amp is NMOS input or PMOS input.
OCMR of about 30% of your supply voltage.

A basic 5 transistor differential amplifier would be able to meet these specifications.

Start from there and then you can try tweaking the circuit to squeeze out more performance.

Many thanks for your advice.