RD O Vo+ Vo- Мa М Vi- Vit Vc VB4 M4 Vc, VB M3 VB3 VB Fig. P1 All transistors are in the saturation region; the transconductances of Mı, M2, M3 and M4 are gml gm2, gm3 and gm4, respectively; the output resistances of Mi, M2, M3 and M4 are rol, To2, To3, and ro4 respectively. Also, gml = gm2 and rol = ro2 >> RD. The tail current source of this differential amplifier is implemented in the cascode structure (M3 and M4), and the load resistors have a very small amount of mismatch, ARD (<< RD). Hint: the output impedance the current source should be the same as the output impedance of a cascode amplifier (a) Derive the expression of the differential-mode gain, Ad = (vo+ - Vo-)((vi+ - Vi.) (b) Derive the expression of the common-mode gain, Ac = \Vo+ - Vo-V/\vel. (c) Derive the expression of the common-mode rejection ratio, CMRR differential amplifier AaAcl for this