Problem $11-(20$ Points$)$: $(10$ pts each$)$

The cascade current source shown below must be designed for a bias current of $1$ mA $.$ Assume

$\backslash$mu $\_($n$)$Cox$=100\backslash$mu $($A$)/($V$^(2))$ and V$\_($TH$)=0\mathrm{.}4$V$.$

$($a$)$ Neglecting channel$-$length modulation, compute the required value of V$\_($b$2).$ What is the

minimum tolerable value of V$\_($bl$)$ if M $2$ must remain in saturation?

$($b$)$ Assuming $\backslash$lambda $=0\mathrm{.}1$V$^(-1),$ calculate the output impedance of the circuit. Show all your work

along with the small$-$signal equivalent circuit.