Question

Consider the circuit shown below:



all the three NMOS transistors in the circuit have

$V_{in}=1V,\lambda =0,{\mu }_n{C}_{ox}=120\mu A/V^2,L_1=L_2=L_3=1\mu m$. The gate widths of $Q_1,Q_{2}and{Q}_3$ are respectively.

Answer 1

$I_{D_1}=I_{D_2}=I_{D_3}=120\mu A$

$\frac{k_{01}}{2}\left(\frac{W_1}{L_1}\right){(1.5-1)}^2=120\mu A$

$\frac{120\times {10}^{-6}}{2}\left(\frac{W_1}{L_1}\right)\left(0.25\right)=120\times {10}^{-6}$

$W_1=\frac{2}{0.25}{L}_1=8\mu m$

$\frac{k_{02}}{2}\left(\frac{W_2}{L_2}\right){(2-1)}^2=120\mu A$

$W_2=2L_2=2\mu m$

$I_{G{S}_1}=I_{G{S}_3}=1.5V$

So, $W_3=8\mu m$