The Infineon CY7C1327G-166AXCT is a synchronous SDR SRAM organized 256K x 18, delivering 4.5 Mbit of volatile storage. It is designed for high-bandwidth applications such as network packet buffers, DSP coefficient tables, and cache memory in telecom or industrial controllers where deterministic read/write cycles at a 166 MHz clock rate are required. The 3.5 ns access time keeps the bus timing tight — this part is meant for a pipelined memory controller that can exploit the synchronous interface, not a legacy asynchronous bus.
166 MHz clock and 3.5 ns access — timing budget decisions
The 166 MHz clock frequency sets the maximum throughput at 332 MB/s for a 18-bit bus (assuming one transfer per cycle). The 3.5 ns access time is the delay from clock edge to data valid; at 166 MHz the cycle period is 6 ns, so the access time consumes just over half the cycle, leaving roughly 2.5 ns for board trace delay, input setup, and clock jitter. That is workable for a point-to-point link on a controlled-impedance PCB, but a heavily loaded bus with multiple slaves will eat into the margin. Plan for series termination and matched trace lengths.
Last Buy — plan your final order window
That means Infineon has announced end-of-life and the final production run is underway or scheduled. Once the last-time-buy window closes, the only source will be surplus or broker inventory. If this SRAM is in a current design, secure the lifetime requirement now — the 100-TQFP footprint is not shared with many drop-in alternatives, so a last-time-buy is the safest path.
The CY7C1327G-166AXCT comes in a 100-TQFP package (14x20 mm body) with a 0.5 mm pitch — a standard footprint for mid-density SRAMs. Supply voltage range is 3.15 V to 3.6 V, so it works on a nominal 3.3 V rail with ±5% tolerance.