## Chapter 4

## Q. 4.5

In the amplifier of Fig. 4-9(*a*), V_{DD} = 15 \text{V}, R_L = 3 kΩ, and R_F = 50 MΩ. If the MOSFET drain characteristics are given by Fig. 4-9(*b*), determine the values of the quiescent quantities.

## Step-by-Step

## Verified Solution

The dc load line is constructed on Fig. 4-9(*b*) with v_{DS} intercept of V_{DD} = 15 \text{V} and i_D intercept of V_{DD}/R_L = 5 \text{mA}. With gate current negligible (see Section 4.3), no voltage appears across R_F, and so V_{GS} = V_{DS}. The *drain-feedback* *bias line* of Fig. 4-9(*b*) is the locus of all points for which V_{GS} = V_{DS}. Since the Q point must lie on both the dc load line and the drain-feedback bias line, their intersection is the Q point. From Fig. 4-9(*b*), I_{DQ} ≈ 2.65 \text{mA} and V_{DSQ} = V_{GSQ} ≈ 6.90 \text{V}.