Async FIFO with 9-bit width — 10 ns access defines the bus window
The Cypress CY7C464A-10JC is a 288K (32K x 9) asynchronous FIFO memory from the CY7C series, built for unidirectional data buffering where the 9th bit carries a parity or control flag alongside the 8-bit data word. Its 10 ns access time sets the read-cycle window: a system clocked at 50 MHz gets one full cycle for address decode, data access, and hold — tight but workable with a 5 V TTL bus. The 32-PLCC package with J-leads is a legacy surface-mount footprint still found on telecom line cards and industrial controller boards that need a simple, no-register depth or width expansion.
Obsolete — sourcing through the surplus channel
That means every unit needs a provenance check — date-code consistency, marking integrity, and lot traceability back to an authorized Cypress shipment. A 32-PLCC package from the 1990s–2000s production window is a common target for re-marked or relabeled stock, so physical authentication (decapsulation, X-ray) is the right screen.
Pin-compatible drop-in? Know the footprint before you substitute
The 32-PLCC (J-Lead) footprint is shared across several Cypress async FIFO densities from the same era — parts like the CY7C42x and CY7C44x series often use the same mechanical outline. But the 9-bit width and 10 ns speed grade narrow the compatible set. A direct replacement must match the JEDEC-standard 32-PLCC pinout, the 4.5 V–5.5 V supply, and the retransmit capability.