A. Parker EE 477L Spring 2007

Homework Assignment #4

Due 2/20/07 12:30 PM

Assume for the problems below that Vdd = 2.5 v, V_tp0 is -.6 v. and V_tn0 is .6 V. V_tpbodyeffect is -.8 v. and V_tnbodyeffect is .8 V.

Assume ß_n (k_n)= 219.4 W/L µ A(microamps)/V² and ß_p (k_p)= 51 W/L µ A/V²

1. (25%) Create a stick diagram from the Euler path you found in Assignment 3 Problem 1, showing PMOS and NMOS diffusion areas, poly, and metal. Put vertical metal connections on metal 1, and horizontal ones on metal 2, including Vdd and Gnd. Use the methodology shown in lecture for the stick diagram. Use purple for metal 2.

2. (10 %) An NMOS transistor has V_DS = .5 V. V_S = 0 V. Is the transistor is in the linear region of operation, when V_GS = 1 V.?

3. (10 %) A PMOS transistor has V_GS =-.9 V , V_DS = -1.9 V. V_S = 2v. What region of operation is it in? Now assume V_GS = -.3 V and V_DS = -2 V. What region of operation is the transistor in?

4.(10 %) Prove that an NMOS transistor passes a weak 1. Does body effect make the 1 stronger or weaker?

5. (10 %) Use the left edge algorithm to connect the common inputs that are in the following order from left to right:

X Y Z X Y W Z V W Y V

Show the stick diagram for the connections, assuming horizontal connections are in metal 1, and vertical ones are in poly.

6*. (10 %) Compute the drain current flow I_DSin an NMOS transistor when V_DS = 1.9 v, and V_GS = 1.7 V. Assume the transistor width is 6 lambda and the length is 2 lambda.

7*. (10%) Compute the drain current flow I_DSin a PMOS transistor when V_DS = -.2 v, and V_GS = -1.7 V. Assume the transistor width is 8 lambda and the length is 3 lambda.

8. (10%) Compute the channel resistance of a PMOS transistor when Vgs = -1.7v and Vds = -.5v.

9. (5%) What is the advantage of using a gate insulating material that has a high dielectric constant?