Homework Assignment #4

Prof. Parker Due Feb. 22, 2004 at 4 PM Solutions will be posted at 8 PM EE 477 Spring 2005

Assume V_dd = 2.5 v. for these problems. Assume V_tp is -.7 V. Assume V_tn is .7 V.

1. For the inverter discussed in class along with the input output transfer curves, assume both PMOS and NMOS devices are in saturation. If V_{in =} .9 v, what is |ß_n/ ßp|? Use the equation from the text.

2. A PMOS transistor has V_GS = -1.9 V. If the transistor is in the saturation region of operation, what are the possible values of V_DS?

3. An NMOS transistor has V_GS = 1.1 V, V_DS = 1.4 V. What region of operation is it in? Now assume V_GS = .41 V and V_DS = 1.6 V. What region of operation is the transistor in?

4 For the circuit shown in the homework 1 solution to problem 1b, which transistor(s) would be subject to the body effect?

5. A transmission gate is in the following state: V_in = 1.5 v. V_out = 2.4 v. At time t=0, the control input turns both transistors on instantaneously. What region of operation is the NMOS transistor in at t=0⁺ ? As t approaches infinity?

6. Will there be a noise problem for an inverter that outputs the voltage range 3.5 v. - 5 v. for a high signal, and recognizes as a high input anything above 3.4 v., if we cascade this inverter to another like it (connect the output of one inverter to the input of another) assuming the noise amplitude is <.15 v.?

<0.8 v.?