Exam Answers

Question 1 1a Sizes: M5 = 8/1; M6 = 64/1

gm1=1066.6 uA/V, Cc=Co=16.977 pF

1c. lambda_n=lambda_p= 0.0356

1d. Stable because wp2=wz=3wu

1e.vx is approximately equal to vc

1f. SR=2.945 V/usec step 0V to close to 2.5V.

Question 2 2a vo/vi = alpha z^{-1}/1-z^{-1} fu/fclock = 1/12.566

2b f=DC, vo/vi = infinity

f=fc/12.566, vo/vi = 1

f=fc/4, vo/vi = 0.35

f=fc/2, vo/vi = 0.25

f=fc/2, vo/vi = 0.25

Plot should show amplitudes modified by sin x/x.

2c Input at fc * 10/9, results at fc * 8/9, fc * 1/9, fc * 17/9, etc. all affected by sin x/x.

Question 3 a. A_DC = 10, fp=5 kHz, fz = 50 kHz high freq gain = 1.

3b. GE = 0.02, corrected gain = 0.98

3c. vc is approx 250 mV (exact is 248.75 mV), vd = 2.5 mV.

Question 4 Circuit ii noise voltage is higher than that of circuit i by sqrt{2}.

4b. 7.5 nV/sqrt{Hz}

4c. 144.05 uV

Question 5 5a) fp=15 kHz, can be SC if done correctly (must explain)

b) bilinear has 90 degrees but freq. warping, in biquad can use one of each of forward and backward Euler integrators.

5c). Discuss methods to minimize noise in terms of W/L, large transconductance of input transistors to minimize thermal noise, Large area input transistors to minimize 1/f noise. Other transistors smaller, lower gm. Calculate inter-relations of noise to W/L, current, area etc.