256Kbit asynchronous SRAM, 15 ns — the bus timing constraint
The CY7C199C-15VXCT is a 256Kbit asynchronous SRAM organized as 32K x 8 bits with a parallel interface. The 15 ns access time sets the window for the memory controller to latch data after address assertion — a 66 MHz bus with a 15 ns cycle budget has zero margin for additional propagation delay through buffers or level shifters. For an industrial enclosure that sees 85°C ambient, the junction temperature exceeds the rated limit — the part is not specified for that environment.
28-SOJ package — footprint and assembly
The 28-SOJ (300 mil body width, J-bend leads) is a legacy surface-mount package. The 1.27 mm lead pitch and J-bend profile match the standard SOJ footprint — no fine-pitch alignment issues. The J-bend gives a smaller footprint than an equivalent SOIC but the solder joint is less inspectable under the body. Supplied in Tape & Reel (TR) — compatible with automated pick-and-place. No moisture sensitivity level is listed; given the package age, assume MSL 3 or higher and bake before reflow if the seal is broken.
For a BOM that requires this exact order code, the only path is the open market.