[MOVED] Op Amp design for required specs

[xaptar]

Hey! I'm new to analog circuit design and am looking to design an op amp that can provide following specs:

DC open loop voltage gain > 100 dB
Unity gain bandwidth > 100 MHz
Phase margin between 70 and 75 degrees at unity gain
Vout swing > 2.0 Vp-p (single-ended)
Load capacitance = 1 pF
Minimum Von for all saturated FETs = 200 mV
Process technology = 0.35μm CMOS
Supply voltages are VDD = 3.3V and VSS = 0V (ground)

Out of 4 common topologies, I thought Folded Cascode will work, but keeping Minimum Von=200mV, I can only achieve gain upto 75dB.
How can I increase gain without disturbing other parameter using folded cascode?

Thanks

 

[balabrahmachari]

Re: Op Amp design for required specs

u can proceed folded cascode with CS as the second stage this will give you the required dc gain.

and it will meet the swing requirement also.


you can keep miller compensation or cascode compensation for the stability.

 

[xaptar]

Re: Op Amp design for required specs

I heard about gain booster, will it work for single ended folded cascode as im trying to avoid common mode feedback, or gain booster will only work with fully differential folded cascode?
Moreover can you kindly give me insight of gain booster , i mean what to add and where and how it will affect the frequency. Thanks

 

[xaptar]

Re: Op Amp design for required specs

so at the output of folded cascode, i will place a common source amp, and it will provide me gain. how can i manage stability, i mean how to apply miller compensation capacitor?
as i said, im new to this