Design Fully Differential Opamp

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shaq

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fully differential class ab output stage

Dear all,

Here is my specification.

Process: TSMC 0.18µm

Voltage: 1.8v

DC gain: ≥70dB

UGBW: ≥55MHz

Slew Rate:≥45V/µs

Phase Margin:≥60°

Can anyone give some suggestions ?
 

fully differencial opamp tutorial

gain boast+cascode
 

dr. vadim ivanov op amp

sunking said:
gain boast+cascode
Click to expand...

How about if I use folded differential opamp + cmfb?
 

It should be okay for fold cascode.
 

u can use foldedcascode 1 stage architecture.gainboostig is the must.for optimizing speed,current must equal in input & cascod devices.
 

I think one-stage folded-cascode is enough,
but you nedd take care to SR
so the tail current may be large
hehe
 

Do u have a linearity spec??
 

Go for folded cascode for achieving these specs
Can we have the power specs as well to be more
accurate ?
 

please provide tutorial to design Folded cascode opamp, or suggest some book or papers..

thank you
 
i don't know the load capacitor's value
if it's large, maybe you can use the class AB output stage, and the first stage is folded-cascode amplifier
for the class AB output stage, Vadim V. Ivanov and J. Baker's book refer to it respectively
good luck
 

Dear Sir/Madam

Since 70dB gain can be achieved with one stage opamp you don't need to use cascading which introduce complex compensation but you can use a simple telescopic cascode with fully differential boosters, remember you have to use CMFB for your opamp and also boosters if they are fully differential. Good luck
 

shaq said:
Dear all,

Here is my specification.

Process: TSMC 0.18µm

Voltage: 1.8v

DC gain: ≥70dB

UGBW: ≥55MHz

Slew Rate:≥45V/µs

Phase Margin:≥60°

Can anyone give some suggestions ?
Click to expand...
 

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