9Mbit synchronous SRAM — 100 MHz, 7.5 ns access, 256K x 36
The Cypress CY7C1355B-100AC is a 9Mbit synchronous SRAM organized as 256K x 36, clocked at 100 MHz with a 7.5 ns access time. It uses a parallel interface and runs from a 3.135V to 3.6V supply.
7.5 ns access at 100 MHz — bus timing margin
In a synchronous system the controller must meet the setup and hold windows relative to this access window. The 100 MHz clock frequency ties the SRAM to the system PLL — if the replacement part runs slower (e.g., 83 MHz), the bus timing budget shrinks and may force a clock divider or a board spin. The 256K x 36 organization means the part handles 36-bit-wide data words in a single cycle, which suits 32-bit plus parity or 36-bit-wide memory buses common in network processors and FPGA-attached caches.
It is not specified for industrial enclosures, outdoor cabinets, or under-hood automotive use. If the replacement design needs -40°C to +85°C, look at the industrial-temperature variants in the same Cypress synchronous SRAM family (e.g., CY7C1355B-100AI) — but verify pin-compatibility separately; the suffix change often means a different ordering code, not a guaranteed drop-in.