Area, Power and Timing Trade-offs · synthesis

Part 6 · Area, Power and Test · Intermediate

5topics
5lessons

Every synthesis run trades area, power, and timing against each other. Tightening one constraint moves the other two, so a fair comparison states all three with EXAMPLE numbers.

Trade-off triangle linking area, power, and timing.

Area, power, and timing form one triangle: pushing any corner moves the other two.

Axis	What it measures	Stated EXAMPLE unit
Area	Cell count times cell size in the teaching library.	Library units of course.lib.
Power	Dynamic plus leakage at stated activity and voltage.	Milliwatts at stated alpha, C, V, f.
Timing	Delay against the clock target, read as slack.	Nanoseconds of EXAMPLE delay.

Lessons

Lesson	What it covers
The three-way trade-off	How one constraint change moves area, power, and timing together.
Dynamic power arithmetic	P = alpha C V squared f with exact EXAMPLE arithmetic and a checker.
Leakage and Vt mixing	Leakage at concept level, Vt mixing, and leakage recovery.
Sizing and duplication cost	What faster cells and duplicated cones cost in area and power.
Fair comparison and Pareto filtering	Fixing two axes, comparing the third, and dropping dominated runs.

Check yourself Run B is faster and smaller than run A but burns more power. Is B better?

Undecided until the budget is stated. B leads on two axes, but if power is the binding constraint, B still fails.

Related topics

Up nextThe Three-Way Trade-Off

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Axis

What it measures

Stated EXAMPLE unit

Area

Cell count times cell size in the teaching library.

Library units of course.lib.

Power

Dynamic plus leakage at stated activity and voltage.

Milliwatts at stated alpha, C, V, f.

Timing

Delay against the clock target, read as slack.

Nanoseconds of EXAMPLE delay.

Lessons

Lesson	What it covers
The three-way trade-off	How one constraint change moves area, power, and timing together.
Dynamic power arithmetic	P = alpha C V squared f with exact EXAMPLE arithmetic and a checker.
Leakage and Vt mixing	Leakage at concept level, Vt mixing, and leakage recovery.
Sizing and duplication cost	What faster cells and duplicated cones cost in area and power.
Fair comparison and Pareto filtering	Fixing two axes, comparing the third, and dropping dominated runs.

Check yourself Run B is faster and smaller than run A but burns more power. Is B better?

Undecided until the budget is stated. B leads on two axes, but if power is the binding constraint, B still fails.