Design an NMOS current source to provide a bias current of $I_Q = 100 \mu A$ and an output resistance greater than $20 M \Omega$. The reference current is to be $I_{REF} = 150 \mu A$. The circuit is to be biased at $\pm 3.3V$ and the voltage at the drain of the current source transistor is to be no smaller than -2.2V. The minimum width to length ratio of the transistor is to be unity.

Given :-

$I_Q = I_O = 100 \mu A$

$R_O = 20 M\Omega$

$I_{REF} = 150 \mu A$

$V^+ = 3.3V$

$V^- = -3.3V$

$V_{DS2(sat)} = -2.2V$

$(\dfrac {W}{L})_1 =(\dfrac {W}{L})_2 = (\dfrac {W}{L})_3 = 1$

Assume $V_{TN} = 0.4V$

Now, $\dfrac {1}{R_O} = \lambda I_O$

Therefore,

$\lambda = \dfrac …