Homework8.10

Homework8.10 - 1.8V c Re-write your solution for part a in...

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ECE 124d/256c Homework 8 Due: Wed March 3, 2010 Reading: DSE chapter 9: a. timing conventions b. open vs. closed loop timing c. phase locked loops d. time borrowing (latch level timing) e. clock distribution Problems: p. 458-460, 9-2, 9-4, 9-7, 9-8 7. Consider a full H-tree clocking scheme which is driven from the center of the die by an arbi- trary large driver. a. If all the wires are the same minimal size with a resistance of 250 ohms per mm and a capaci- tance of 0.28 pF/mm, what is the largest area that can be clocked before the rise time at the termi- nal increases beyond 200pS? Keep your answer in terms of N, the total number of load points. b. For the above situation, what is the total capacitance of such a maximal tree driving 4 8 flip flop loads if each load is 7fF? How much power will this tree dissipate if clocked at 200MHz and
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Unformatted text preview: 1.8V? c. Re-write your solution for part a in terms of area A given a uniform density of load points d (loads per unit area) with 7fF loads at each point. 8. Consider a clock grid consisting of a square lattice of minimal size wires, each with a resistance of 250 Ω /mm, a capacitance of 0.28pF/mm and a grid pitch (wire to wire spacing) of 25um. If driven from the center, what is the largest size that can be clocked before the rise time of the ter-minals increases beyond 200pS? b. If the grid wires above are sized to carry the same current density per segment, and drive a total unifrom load of capacitance 700pF in addition to the grid capacitance, how do you set the wire sizes of the grid as afunction of the radial distance from the center?...
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This note was uploaded on 12/04/2010 for the course ECE 134 taught by Professor York during the Fall '08 term at UCSB.

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