15 ns asynchronous SRAM — 64K x 16, 5 V supply
The CY7C1021B-15ZXC: It uses a parallel memory interface and comes in a 44-pin TSOP II package for surface-mount assembly. This is a 5 V-only part, designed for legacy bus architectures and systems that still run on a 5 V rail.
15 ns access time — bus timing margin
For a processor running at 33 MHz (30 ns cycle), this leaves about 15 ns of margin after address setup — enough for a zero-wait-state interface with most 16-bit controllers from the 1990s and early 2000s.
64K x 16 organization — direct fit for 16-bit data bus
The 64K x 16 organization maps directly to a 16-bit data bus without external byte-lane muxing. This saves board area and reduces propagation delay compared to using two 8-bit-wide SRAMs. The 1 Mbit density suits moderate-sized data buffers, scratchpad memory, or cache in embedded systems.
5 V supply — compatibility check
It is compatible with 5 V TTL and CMOS logic families. Do not use it in a 3.3 V-only system without a level translator — the minimum supply is 4.5 V.
The CY7C1021B-15ZXC is marked as obsolete by Infineon (formerly Cypress).