A MOS differential amplifier utilizing a simple current sour

A MOS differential amplifier utilizing a simple current source to provide the bias current I is found to have a CMRR of 60 dB. If it is required to raise the CMRR to 100 dB by adding a cascode transistor to the current source, what must the intrinsic gain A₀ of the cascode transistor be? If the cascode transistor is operated at Vov = 0.2 V, what must its V_A be? If for the specific technology utilized V\'_A= 10 V/um, specify the channel length L of the cascode transistor.

Solution

CMRR = Ad/Ac

Vo = Ad*Vd + Ac* Vc= 0.2

L = CMRR/Vo

= 4.5m

CMRR = 100 dB

its value = 10⁵