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How can I calculate the W/L of these transistors

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wjxcom

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Please look at this OPA. The specifications is:

Gain=5000
Gain bandwidth=10MHz when a 10pF load
Slew rate=10V/us when a 50pF load
ICMR=1.5-4V
Output swing=1-4V
Vdd=5V

From these parameters, I can calculate the W/L of these transistors: M12, M13, M14, M19 and M24. But I do not know how

to calculate the W/L of the rest transistors. I think there has no enough parameter to calculate the W/L of these

transistors.

How can I calculate the W/L of these transistors? Help me!!
 

hylas

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Bias M22 and M23 to fullfill gm23/Cg24 > UGF

Others depend on your bias current budget.
 

chen_Analog

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why it is necessary for Bias M22 and M23 to fullfill gm23/Cg24 > UGF ?
 

hylas

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chen_Analog said:
why it is necessary for Bias M22 and M23 to fullfill gm23/Cg24 > UGF ?

M22 and M23 form a buffer stage with output impedance of ~ 1/gm23. It generates a non-dominant pole which should be placed after the UGF.
 

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