The CY7C1399BL-12ZXCT is a 256Kbit asynchronous SRAM organized as 32K x 8, with a 12 ns access time.
Cypress (now Infineon) no longer manufactures the CY7C1399BL-12ZXCT in volume. For BOM lines that need this exact footprint and timing, the supply channel is independent distribution — surplus stock, new-old-stock, or broker inventory. The 28-TSSOP package is the footprint to match if evaluating alternatives.
This limits the part to indoor, temperature-controlled environments — office equipment, telecom racks with active cooling, benchtop instruments, or appliance control boards. Not suitable for outdoor, automotive, or industrial enclosures where the ambient drifts outside that window.