# ENEE 411 Circuit, Resistance And Voltage Homework 2 Answer

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## Question :

ENEE 411 Summer 2022

Homework 2

1. Problems 6.24 (Baker 4th ed) (60 points)

Estimate, in terms of VDD and IOFFn,p (the off current of either the NMOS or PMOS devices), the power dissipated in each of the following circuits. Which device dissipates power in each circuit?

2. Problems 9.5 (Baker 4th ed) (60 points)

Calculate ID, VDS,  and estimate the small-signal resistance looking into the drain of the MOSFET in the following circuit.

3. Problem 9.33 (Baker 4th ed) (40 points)

Using the process data for short-channel (50 nm) length MOSFET, and the square-law equations, determine the DC voltage,Vin each of the following circuits.

4. Problem 9.38 & 9.39 (Baker 4th ed) (50 points)

Estimate the AC current, iithat flows in the test voltage vT (1 mV at 1 MHz) in the circuits shown below (and thus what is the small-signal resistance, vT/iiT, seen by vT?) Use the process data for short-channel (50 nm) length MOSFET. What would happen to the DC biasing of the MOSFET if the capacitor was removed so that the test voltage was connected directly to the drain? Hints: the AC current flowing through the resistor is   vT /R while the AC current flowing in the MOSFET is either vT/ro (for saturation region operation, see Eq. [9.6] in Baker) or

vT/Rcℎ  VT/Rch for triode operation (see Eq. [9.16] in Baker). The resistance seen by vT is then the parallel combination of the resistors.

5. Problem 20.1 (Baker 4th ed) (50 points)

Using the CMOS long-channel process (1μm), determine the current flowing in the circuit seen below.

6. Using the CMOS long-channel process (1μm), calculate the currents and voltages in the circuit seen below. What is the maximum value allowed for R2 so that M2 remains operating in the saturation region?

7. Problem 21.3 (Baker 4th ed) (50 points)

Estimate the frequency response of the circuit seen below if the amplifier drives a 100 load capacitance.

8. Using the CMOS long-channel process (μm), estimate the AC and DC drain currents in the circuit seen in the figure below. What are
vgs1 and vgs2? What happens to the DC biasing if we replace the capacitor with a short? What happens, with the capacitor in place, to the DC biasing if we short the big resistor (show that the DC biasing isn't affected; however, the amount of AC current supplied by vin goes up). How do the currents in M2 change if we double its width (put two 10/2 transistors in parallel)?