Homework Assignment #2
EE 477 Spring 2017 Professor Parker
Hardcopies due in EE 477 box in EEB Basement 5 PM Feb 7, 2017
OR Ecopies due 5 PM Feb 7, 2017 using Assignment Dropbox on DEN
To ensure academic privacy, please use a cover page on your homework hard copies that does not contain any work.
Question 1: Consider the following circuit. At time t = 0, nodes Vx, Vy and Vout are completely discharged (0 Volts). Given: Vdd = 1.8V and VtN = 0.5V when there is no body effect.
a) (3%) Show the source and drain of each transistor on the diagram
b) (6%) What region is each transistor in at t = 0?
c) (6%) Solve for Vx, Vy and Vout at t = ∞. Ignore body effect.
d) (6%) What region is each transistor in at t = ∞?
e) (3%) Qualitatively describe what happens to Vx, Vy and Vout if you take body effect into account. Do they increase or decrease?
Question 2: The NMOS shown is in linear region.
a) (12%) What are the regions of operation of the NMOS and PMOS as Vout changes over time? Show your calculations.
b) (5%) Is there any region of operation where it is impossible for the NMOS or PMOS to be in? If yes, why?
Question 4: Ids-Vds curves for NMOS transistors are shown below.
a) (3%) What is the red curve?
b) (15%) Draw similar curves for PMOS transistors.
Question 5: Consider the CMOS inverter shown. Given: VtN = -VtP = 0.4 V and Kn = Kp
a) (15%) Make an initial guess regarding the regions of operation of each transistor based on the analysis done in lecture (refer to the Vout vs Vin curve for inverter). Based on your guess, write the current equations of each transistor and solve for Vout. Big hint: Don’t consider both transistors to be in saturation because then you can’t solve for Vout.
b) (5%) Is the calculated Vout consistent with your guess? If not, make a different guess and solve again.