Subject: CMOS VLSI Design

Topic: Single Stage Amplifier

Difficulty: Medium

For MOSFET in saturation,
$\hspace{2cm}I_D=\frac{1}{2}\mu_n C_{OX}\frac{W}{L}(V_{GS}-V_{th})^2$

where, $(V_{GS}-V_{th})$ -> $I_D$ dependant on square of overdrive voltage.

• In some applications, square law dependence of $I_D$ on overdrive voltage introduces excessive non-linearity.

• Solution: using diode connected load.

• Another approach: Using source degeneration resistor.

• As $V_{in}$ increases, $I_D$ increases, voltage drop across $R_S$ …