Path Balancing Overhead Lab

Pads synchronize epochs — they do not compute new Boolean function. Public rule: k = n_long − n_short on the short path. Overhead costs area, bias, clock leaves, and latency.

Long path stages (n_l)

Short path stages (n_s)

“Logic” JJ (illustrative)

JJ per pad (illustrative)

k = 5 − 2 = 3 pads on the short path

k needed

Pads applied

Balanced?

Pad JJ

f_pad sketch

Short vs long into merge — orange boxes = overhead pads (not Boolean logic)

Illustrative junction stack (not a paper % — teaching sketch only)

logic

Area / JJ80 logic + 0 pad

Clock leaves+0 for pads

Bias taps+0 (cartoon)

Latencyshort path +0 epochs

Clock style does not cancel k. Concurrent or counter-flow still needs matched epochs at the merge. Recount depths after each merge — balancing is global, not a one-sticker fix.