64Kbit dual-port SRAM for shared-memory arbitration
The Cypress CY7C024-25JXC is a 64Kbit asynchronous dual-port SRAM organized as 4K x 16 bits, with a 25 ns access time that defines the bus-turnaround window when two processors or controllers share a memory block. The 84-PLCC package with J-leads (29.31 mm body) is a through-hole-solder or socketed footprint, common in telecom line cards and industrial controller boards from the late-1990s through mid-2000s designs.
25 ns access — timing margin in a shared bus
The 25 ns access time (matched by the 25 ns write cycle) sets the minimum arbitration slot: each port must complete its read or write within one 25 ns window before the other port can claim the bus. In a system with a 20 MHz or slower host, this leaves comfortable margin; at 33 MHz the designer needs to account for the 25 ns ceiling in the bus-hold and wait-state logic. That simplifies timing closure but means the designer cannot pipeline the arbitration; the 25 ns is a hard latency budget for every access.
Any inventory in the channel is new-old-stock or surplus from prior production runs.