20-PLCC J-Lead — legacy footprint, rework profile matters
The Microchip ATF16V8BQL-15JU is an electrically erasable PLD from the 16V8 family, offering 8 macrocells with a 15 ns propagation delay at a 5V supply. It comes in a 20-LCC package with J-leads (20-PLCC), a legacy surface-mount form factor that requires a hot-air rework profile — the J-lead wets differently than gull-wing, and the PLCC body absorbs moisture, so a bake cycle per J-STD-033 is recommended before reflow if the floor life has been exceeded.
15 ns speed grade — timing closure for 5V glue logic
The 15 ns propagation delay (tpd) sets the maximum operating frequency for registered logic at roughly 66 MHz, assuming a 50% duty cycle and no additional routing delay. For combinatorial paths, the 15 ns window must accommodate the sum of PLD delay, interconnect, and receiver setup time — a common constraint in address decoding for legacy 5V bus systems. The 5V input voltage is fixed; no 3.3V or 1.8V core option exists, so level translation is required when interfacing with lower-voltage peripherals.