RSFQ DFF Lab

Capture a data pulse into the storage loop (circulating Φ₀ = “1”). Hold — the output pin is not a CMOS high; the bit lives in the loop. Clock reads: full → output pulse + clear (destructive); empty → silence.

EMPTY (0)
Loop
empty
Data in
0
Clocks
0
Out pulses
0
Last event
—
DATA → storage loop ← CLOCK · OUT speaks only at readout
# Action Before After OUT pulse? Note
Inject data (fill), then fire clock (emit + clear). Or clock an empty loop (no OUT).

Destructive readout is the default teaching model (NDRO exists later as vocabulary). A second data pulse into an already-full loop is a library-dependent hazard — flagged here as WARN. DFF pads for path balancing still need clock-tree leaves.