+3V Ry = 3 k2 R1 = 100 k2 V: R₁ || R₂ Vi R2 = 200k2 Ry = 10 k2 Vsg + S -3 V (a) (b) Figure 4.20 (a) PMOS circuit for Example 4.5, and (b) small-signal equivalent circuit Rs D 8mVsg ww RD EXAMPLE 4.5 Objective: Determine ID, circuit. V SG' SD Vs and the small - signal voltage gain of a PMOS transistor Consider the circuit shown in Figure 4.20(a). The transistor parameters are A K = 0.80m- V Р _2’TP = 0.5V, and λ = 0 V

Explain the steps

Objective: Determine the small-signal voltage gain of a circuit biased with a constant- current source and incorporating a source bypass capacitor. +5 V Rp = 7 kn For the circuit shown in Figure 4.21, the transistor parameters are: VTN = 0.8 V, K, = 1 mA/V?, and = 0. o vo RG= 200 k2 +Cs lo = 0.5 mA 4 -5 V

n EXERCISE PROBLEM Ex 4.5: For the circuit shown in Figure 4.19, the transistor parameters are VTN = 0.8 V, K₂ = 1 mA/V², and λ = 0. (a) From the dc analysis, find ID and VDSQ. (b) Determine the small-signal voltage gain. (Ans. (a) ID = 0.494 mA, VDSQ = 6.30 V; (b) A₁ = -5.78).

EXERCISE PROBLEM Ex 4.6: The common-source amplifier in Figure 4.23 has transistor parameters = 40 μA/V², W/L = 40, VTP = −0.4 V, and λ = 0.02 V-1. (a) Determine IDQ and VSDQ. (b) Find the small-signal voltage gain. (Ans. (a) IDQ = 1.16 mA, VSDQ = 2.29 V; (b) A₁ = -3.68) CCI Vi www +3 V Rs = 1.2 k RG = 100 k - Vo RD = 2 k -3 V Figure 4.23 Figure for Exercise Ex 4.6 Cs

EXERCISE PROBLEM Ex 4.2: For the circuit shown in Figure 4.1, VDD = 3.3 V and RD = 10 ks. The transistor parameters are VTN = 0.4 V, k = 100 μA/V², W/L = 50, and λ= 0.025 V1. Assume the transistor is biased such that IDQ = 0.25 mA. (a) Verify that the transistor is biased in the saturation region. (b) Determine the small- signal parameters gm and ro. (c) Determine the small-signal voltage gain. (Ans. (a) VGsQ = 0.716 V and VDSQ = 0.8 V so that VDS > VDs (sat); (b) gm 1.58 mA/V, ro = 160 ks2; (c) -14.9)

Small Signal Analysis Vcc Ves Problem #4 - Vcc 4а) For the circuit shown to the right, draw the Ry Vour small signal equivalent circuit (including r.). Be sure to label everything (e.g., Vbe, gm, etc.) Do not assume identical transistors (i.e., keep all subscripts). Use Qz correct small signal notation! 4b) For the small signal equivalent circuit shown on the right, solve for Rin. Do not assume identical transistors. Vbei 9m2 Vbe2 R 02 Vbez D

d. For the common-base configuration, an ac signal of 10 mV is applied, resulting in an ac emitter current of 0.5 mA. If alpha is 0.980 and RL = 1.2 k2, determine Zj. Vo, and Ay.

QUESTION 4 a) Discuss four advantages of field effect transistor (FET) over bipolar junction transistor (BJT). b) With the aid of suitable diagrams, explain the primary difference between n-channel depletion and enhancement type metal oxide semiconductor field effect transistors (MOSFETS).

5- a-) Define the MOSFET in the figure, explain by drawing its input and output circuit characteristics.b-) Since k=0.1 mA/V2, VGS=5V and VT=2.5V for this MOSFET, find the VDS voltage using the circuit.