How to calculate the value of the bias voltage?

[shaq]

Hi...

Can anyone tell me if I hope the ID of M0 is 22µA, how to calculate the value of the bias voltage(Vb3) to meet my specification ?

And, help me to determine the (W/L) of M1&M2.

Thank you for your help!!!!

P.S. The source of M0 connected to VDD=3v.

-----Spec.---------------------------------
DC Gain (A0) >75dB
Unity Gain BAndwidth >40MHz

Input Common-Mode Range : 0.5~2.5v
---------------------------------------------

 

[vbhupendra]

Vb3= VDD - sqrt[(2*ID)/(kW/L)] + Vthp

 

[shaq]

Vb3= VDD - sqrt[(2*ID)/(kW/L)] + Vthp

Dear vbhupendra,

But my max. common-mode voltage is 2.5v.

If I use your formula to get the Vb3=1.37v, the M0 is in linear region.

I think the reason of M0 in linear region is relation to M1(or M2).

oh..my...

Could someone give a hand?

 

[vbhupendra]

use

Vimax = VDD - VDS0 - VGS1

Vimax = VDD - sqrt[(2*ID0)/(kW0/L0)] - sqrt[(ID0)/(kW1/L1)]