The Infineon CY7C025-25AC is a 128Kbit dual-port asynchronous SRAM organized as 8K x 16 bits. It provides two independent ports with separate address, data, and control lines, allowing simultaneous read/write access from two bus masters or processors. The 25 ns access time sets the bus-cycle timing for shared-memory arbitration in multiprocessor systems, FIFO buffers, or video frame stores.
25 ns access time — the bus-margin decision
In a system with a 40 MHz bus clock (25 ns period), this leaves essentially zero margin for address-to-data setup before the next clock edge. That means the CY7C025-25AC is best matched to slower bus domains (20 MHz or below) or to designs that insert a wait state. If your bus runs faster than 25 ns, you need a faster dual-port SRAM — the CY7C025 family had -15 and -20 speed grades for those cases.
Infineon (formerly Cypress) lists the CY7C025-25AC as obsolete.
Package and footprint — 100-LQFP (14x14 mm)
The board layout must account for the 5V supply rail and the decoupling capacitance needed to support simultaneous port switching. The part ships in bag form, not tape-and-reel, so it is handled as tray or tube inventory at the distributor.