Electrical Engineering Archive: Questions from 2024-06-13

Question 1. Cascode Amplifier In the circuit below, assume μnCox(W/L)1 = μnCox(W/L)2 = 1 mA/V2, ID1 = ID2 = 0.55 mA, VDD = 3.1 V, Vth = 1 V, λ = 0.1, and RD = 2 kΩ (neglect body effect) (a) Calculate VB and VIN such that M1 is exactly at saturation (VDS = VGS−Vth) (b) Draw small signal model and calculate small signal gain vout/vin Figure 1. Cascode Amplifier

For the MOS-FET based voltage amplifier shown in Fig. 4 ; consider "Vb" as a DC battery, transistors M1 & M2 have different transconductance parameters as well as different Early voltages (K1 ≠ K2 & VA1 ≠ VA2). Derive expressions for: Mid-band voltage gain "Vout /Vin" (15 marks) Input resistance and output resistance (10 marks) Note: Don't neglect the channel length modulation effect for both transistors Figure 4 MOS-FET Voltage Amplifier

Determine the Thévenin equivalent network seen by diode D in Figure P9.19, and use it to determine the diode current iD. Also, solve for the currents i1 and i2. Assume R1 = 5 kΩ, R2 = 3 kΩ, Vcc = 10 V, and Vdd = 15 V. Figure P9.19

Figure 3 Consider the amplifier circuit shown in Fig 3. Assume the MOSFET operates in active region. MOSFET parameter are kp′W L = 1 mA/V2 and |Vtp| = 1 V. Find the ratio R2/R1 for gm = 4 mA/V.