Q1VLSI Design

Question

Q.1. Write down the equations for Ids of an n-channel enhancement MOSFET operating in Non-saturated region and saturated region. [2]

Answer 1

I_{D S} = k_{n} [(V_{GS} - V_{T}) V_{D S} - \frac{V _{D S}^{2}}{2}] (non-saturation/triode), I_{D S} = \frac{k _{n}}{2} (V_{GS} - V_{T})^{2} (saturation)

In the non-saturation (triode/linear) region, valid when VDS is less than (VGS-VT), the drain current depends on both VGS and VDS as shown above, where kn=mu_nCox(W/L) is the process transconductance parameter. In the saturation region, valid when VDS is greater than or equal to (VGS-VT), the channel pinches off near the drain and the current becomes essentially independent of VDS (in the ideal square-law model), depending only on the gate overdrive (VGS-VT) squared.

Q1VLSI Design

Question

Answer