64K x 16 — why the 16-bit width matters
The 64K x 16 organization matches the native data bus width of 16-bit MCUs and DSPs, so a single chip delivers the full word in one access cycle. A design that needs 1 Mbit of SRAM on an 8-bit bus would use two 512 Kbit x 8 parts and twice the board area; this part collapses that into one 44-TSOP II footprint. The 15 ns write cycle time — same as the read access — keeps back-to-back writes tight, which matters when the controller is bursting data into a frame buffer or trace log.
Infineon lists the CY7C1021BN-15ZSXE as obsolete. That means no further factory orders, no last-time-buy window, and no official successor part number from Infineon.
44-TSOP II — footprint and handling
The 44-TSOP II package (0.400 inch body width, 10.16 mm) is a standard thin small-outline package with gull-wing leads on 0.8 mm pitch. It is surface-mount only, so the reflow profile follows the standard JEDEC MSL rating — verify the moisture sensitivity level on the bag before baking.