Chapter 4, Problem 4.1EP

To determine

The value of width to length ratio for given values.

Answer to Problem 4.1EP

  $\left(\frac{W}{L}\right)=20.25$ .

Explanation of Solution

Given information:

The given values are

  $\begin{array}{l}{I}_{DQ}=0.8\text{mA}\\ V_{TN}=0.6\text{V}\\ k_n\text{'}=100{\text{μA/V}}^{\text{2}}=0.1m{\text{A/V}}^{\text{2}}\\ g_m=1.8\text{mA/V}\end{array}$

Calculation:

The value for W / Lis given by

  $\begin{array}{l}{g}_m=2\sqrt{\left(\frac{k_n{}^{\text{'}}}{2}\right)\left(\frac{W}{L}\right)I_{DQ}}\\ 1.8=2\sqrt{\left(\frac{0.1}{2}\right)\left(\frac{W}{L}\right)0.8}\\ \left(\frac{W}{L}\right)=20.25\end{array}$