The GAL16V8D-15LJI: The 15 ns max propagation delay (tpd) is the time from input pin crossing the threshold to output pin reaching valid logic level — this sets the combinatorial logic path ceiling. In a registered design the clock-to-output delay plus setup time of the next device must fit within one clock period; at 15 ns the safe clock rate for a single logic layer is roughly 66 MHz, assuming zero routing delay. If your board runs 3.3 V only, this part needs a separate supply or a level translator on the I/O. The 20-PLCC (J-Lead) footprint matches the industry-standard PLCC-20 land pattern; the 9x9 mm body fits a socket or direct solder.
Lattice Semiconductor lists the GAL16V8D-15LJI as obsolete. Quantities are lot-specific and confirmed at RFQ. The 8 macrocells handle glue-logic consolidation — address decoding, bus arbitration, state machines — that would otherwise consume multiple 7400-series logic packages.