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Help me design a two stage op amp in Cadence

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xanhphysics

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Hi everybody .
I 'm a new beginner in electronic . I got a specification which need design by Candece .Unfortuately , I m not sure which topology i should choose for my deisgin.
This is my specification :
Design a two stage op amp which satisfy :
Using 0.18u technology :
Vdd=1.8 V
Gain>60db
Gain BW >5MHz
Setting <0.5us
Output Swing =1v
Diffential in differential out
off set <10mv
CMRR>60dB
noise <50nv/sqrt(hz) at 1khz
could you guide me more detail which topology i should choose for my device>
Thanks you so much .
 

Ugent Need help

topology?

they have n exapmple fr this in CDSDOC!
 

Ugent Need help

hi ,what i mean .
Base on the specification , i 'm not sure the first stage should be fold cascode or telescopic cascode ? then how to satisfy my specification ?

HI Candece UK for you help >
could you pls tell me what is CDSDOC?

Added after 2 minutes:

further where i can find this example
 

Re: Ugent Need help

CDSDOC is the documentation/help for the cadence design package. If it is correctly installed you can just type 'cdsdoc' from the terminal to start it.
 

Re: Ugent Need help

As the supply voltage is 1.8V, I think the folded-cascode topology is more suitable for you.
 

Ugent Need help

Hi, by using any ordinary two stage opamp, you can design it easily.
If you want an example, u can see the allen-holberg book. They gave very nice example for beginners in the "opamp" chapter.
u can follow the test circuits given there, to check your specifications
 

Ugent Need help

thank you all for your help .I will follow your help .
I got one quetions,need help . Could you pls guide me how to choose w/L to satisfy requirement ?
 

Ugent Need help

take l = 180 n w= 240


ds aspect ration seems fine!
 

Ugent Need help

(W/L) value has to be determined from the current equation, based on the requirements.
 

Ugent Need help

But depend on Bias current .In the reuirement ,it dun give out the power dissipation .Then how to choose correct bias current ? Thanks
 

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