The 10 ns access time means this part can service a cache-line fill or DSP data fetch without wait states in systems with bus cycles down to 10 ns — a 100 MHz equivalent read rate. The 256K x 4 organization targets designs that need a narrow 4-bit data path, such as deep FIFO buffers, network switch port memories, or glue-logic storage in legacy telecom line cards.
Package and footprint — 28-SOJ surface-mount
The J-bend leads save board area compared to a DIP, but the 0.300" body is wider than the more common 0.150" SOJ footprint — verify the pad layout against your existing 28-SOJ land pattern before committing the BOM. The part ships in Tube form, not Tape & Reel, which affects pick-and-place feeder setup for volume production.
Infineon (formerly Cypress Semiconductor) has designated the CY7C1006D-10VXI as Obsolete. For new designs, consider a current-production asynchronous SRAM in a compatible 28-SOJ footprint with a 5 V supply and 10 ns or faster access time. No last-time-buy window remains; procurement should qualify the part from a trusted broker channel with date-code and counterfeit screening.