MT23: the 2023 midterm
The Fall 2023 midterm (October 19, 2023; 150 points). Work through it in order: each part gives its question in short and links to the page that solves it. MT23-5 already has its exam way; those of M3, M5 and M6 come with their rebuild in early December.
16 parts: all solved in the guide, 4 with an exam way.
MT23-1
MT23-1a (10 points)
A chain of N 2W/W inverters with a side load: the energy drawn from the supply per , as a function of N and W.
MT23-1b (8 points)
The subthreshold leakage energy of the N inverters per cycle at 300 K.
MT23-1c (8 points)
With equal to the chain’s delay, the ratio of leakage energy to total energy.
MT23-1d (8 points)
The W that minimizes the product of (a)‘s energy and the chain’s delay.
MT23-2
MT23-2a (8 points)
A complementary pass-transistor circuit: is it static CMOS? Explain.
MT23-2b (16 points)
What logic function does it give at outputs D and E?
MT23-2c (10 points)
The lowest logic high and the highest logic low at D and E, and the inputs that give them.
MT23-3
MT23-3a (8 points)
A domino gate: Y as a function of A and B.
MT23-3b (10 points)
With M4 = 10 µm and the other devices 3 µm, the delay from B falling to Y falling (M4 four times stronger than M3).
MT23-3c (8 points)
With M4 four times stronger than M3, how do the inverter’s DC noise margins compare with equal sizing?
MT23-3d (6 points)
How could one added transistor improve on ?
MT23-4 (10 points)
Draw the schematic of a stick layout and give its logic function.
MT23-5
MT23-5a (10 points)
A path of static gates with equal-strength devices: the A-to-E delay as drawn.
MT23-5b (10 points)
Keep µm and size – for minimum delay; give the new delay.
MT23-5c (10 points)
A 25 fF side load is added: the delay with (b)‘s sizes.
MT23-5d (10 points)
Retune the modified circuit, still fixed, and give the new delay.