The ATF16V8BQL-15PI is a 5V-only electrically erasable PLD from Microchip's 16V8 family, offering 8 macrocells with a 15 ns propagation delay. The 20-pin DIP package (0.300-inch body) is a through-hole legacy footprint — still common in industrial controller cards, test equipment, and retrofit designs where a socketed PLD is preferred for field updates. The EE programmable type means the device can be erased and reprogrammed electrically without UV light, simplifying development iterations and field reconfiguration.
Microchip lists the ATF16V8BQL-15PI as Obsolete. For existing designs already using the -15PI, the remaining supply is limited to surplus and broker inventory. If your BOM has a second-source requirement, the 16V8 architecture is widely second-sourced — the Lattice GAL16V8D and the Cypress (now Infineon) PALCE16V8 are functional equivalents in the same 20-pin DIP footprint, though verify programming algorithm compatibility with your programmer.
8 macrocells and 5V-only — where it still fits
Eight macrocells give you roughly 8 to 10 sum-of-products terms per output — enough for a state machine with 4-6 states, a 3-to-8 address decoder, or a handful of combinatorial gates. The 5V-only supply rail ties it to legacy 5V TTL/CMOS logic families (74HC, 74HCT, 74LS); it will not work in a 3.3V or 1.8V core system without level shifters on every I/O. The 20-PDIP package is socket-friendly and hand-solderable, which matters for prototyping and low-volume production where rework is common. If your board is already running 5V and you need a small PLD for a known function, this part is a direct fit — but the obsolescence clock is running.