| 1. | Explain how to bias (in the forward or reverse condition) the B-E junction and theB-C junction of a pnp BJT to keep the BJT in (1) the active mode and (2) the saturation mode (25%). |
| 2. | We may use the common-emitter amplifier with a single BJT to amplify a signal.However, as the circuit shownin figure 1, why do we need to employ two BJTs (Q1 and Q2) connected as a differential pair with the base of Q2 being grounded on an IC chip (25%)? |
| 3. | Assume that the amplifier transfer function T(s) equals to V0(s)/V1(s) (as shown in Fig. 2). Find all its zeros (25%). |
| 4. | Assume the threshold voltages of all devices in Fig. 3 to be equal in magnitude. Note that k denotes 1/2μ CoxW/L. In the event thatk 1 = k2 and k 3 = k4 =9k1,find the required value of I1 to yield a bias current in Q3 and Q 4of 0.9mA (25%). |
