128K x 8 asynchronous SRAM — 15 ns access, 5 V supply
The CY7C109BN-15ZXC is a 1 Mbit asynchronous SRAM organized as 128K x 8 bits, with a 15 ns access time that sets the bus cycle ceiling for a standard parallel interface. The 4.5V to 5.5V supply rail matches legacy 5 V logic families — no level translation needed when connecting to 5 V CPLDs or older microcontrollers. The 15 ns write cycle time (word, page) matches the read access, so back-to-back read-write operations run at the same bus speed without wait states. This is a volatile memory — data is lost at power-down; typical use is as a fast scratchpad, cache buffer, or configuration store in embedded systems.
Infineon has discontinued production; no future manufacturing is planned. Sourcing is limited to inventory already in the channel — broker-held stock, surplus lots, or authorized overstock with remaining shelf life. When sourcing from open market, verify date code and moisture sensitivity level (MSL) against the original Cypress/Infineon datasheet — older trays may have been stored outside recommended conditions.
Commercial temperature grade — indoor use only
If the BOM requires a wider temperature grade, a different SRAM in the same package but with industrial or automotive qualification would be needed — expect a different base product number and likely a different supply voltage range.