Lattice Semiconductor has marked the GAL16V8D-15QP as Obsolete.
15 ns — the speed grade that sets the ceiling
The 15 ns maximum propagation delay (tpd(1)) defines the combinational path limit. For a registered design, the internal flip-flop toggle rate is gated by this delay plus the external clock-to-output timing — the part will not sustain a system clock above roughly 66 MHz in a typical path. Eight macrocells, each configurable as registered or combinatorial, give the GAL16V8D-15QP the same logic density as the original PAL architecture it replaces.
20-pin DIP — board-fit constraints
The 0.100-inch pitch row spacing is standard for 300-mil DIP sockets; the 0.015-inch square pin cross-section accepts wire-wrap or solder-tail termination. No exposed pad or thermal slug — heat dissipation is through the leads into the copper trace.