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Buffer Construction
how many stages? how to size?

Measure delay per wire...

  1. total number of
    inverter stages:
    2, 3, or 4?
    • 3 stages (inverting!)

  2. Wp/Wn of sense stage?
    • 1/2 (low-swing input)

  3. Wp/Wn of intermediate stages?
    • 1.5/1 (lowest delay)

  4. Wp/Wn of drive stage?
    • 1/1 (tristate weakens pullup)

  5. tristate output:
    • uses pass transistor
    • reduced drive
    • smaller area



General buffer construction.