Description
1. Consider the circuit of Figure. The capacitors are very large, so they discharge only a very small amount per cycle. Sketch the voltage at point A versus time. Find the voltage across the load. Why is this called a voltage doubler? What is the peak inverse voltage across each diode? (10 points)
2. Two points in the saturation region of a certain NMOS transistor are (vGS = 2 V, iD = 0.2mA) and (vGS = 3 V, iD = 1.8 mA). Determine the values of Vto and K for this transistor. (10 points)
3. Given that the enhancement transistor shown in Figure P12.14 has Vto = 1 V and K = 0.5 mA/V2, find the value of the resistance R. (10 points)
4. A p-channel enhancement MOSFET has Vto = – 0.5 V and K = 0.2 mA/V2. Assuming operation in the saturation region, what value of vGS is required for iD = 0.8 mA? (10 points)
5. Find IDQ and VDSQ for the circuit shown in Figure. The MOSFET has Vto = 1V and K = 0.25 mA/V2. (10 points)
6. Find IDQ and VDSQ for the circuit shown in Figure. The MOSFET has Vto = 1V and K = 0.25 mA/V2. (10 points)
7. In transistor small signal analysis, give definitions of gm and rd as partial derivatives. (5 points)
8. Suppose that we have an unusual type of FET for which iD = 3 “#%+ 0.1vDS
Here, iD is in mA, vGS is in volts, and vDS is in volts. Determine the values of gm and rd for a Q point of VGSQ = 1 V and VDSQ = 10V. (10 points)
9. Draw the circuit diagram of a two-input CMOS AND gate. (Hint: Use a two-input NAND followed by an inverter.) (10 points)
10. Find VDSQ and IDQ for the FET shown in Figure, given Vto = 3 V and K = 0.5 mA/V2. Find the value of gm at the operating point. Draw the small-signal equivalent circuit, assuming that rd = ∞. Derive an expression for the resistance Ro in terms of RD and gm. Evaluate the expression for the values given. (15 points)
