Design Fully Differential Opamp

[shaq]

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 ?

 

[sunking]

fully differencial opamp tutorial

gain boast+cascode

 

[shaq]

dr. vadim ivanov op amp

gain boast+cascode

How about if I use folded differential opamp + cmfb?

 

[pfd001]

It should be okay for fold cascode.

 

[kiarash.gharibdoust]

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

 

[Alan_Nesta]

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

 

[MSSN]

Do u have a linearity spec??

 

[raduga_in]

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

 

[rajharvijay]

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

thank you

 

[gingerjiang]

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

 

[s_babayan]

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

 

[karim365]

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 ?