DDR II SRAM for high-throughput data buffers
The Infineon CY7C1320KV18-250BZXC is a 18 Mbit synchronous DDR II SRAM organized as 512K x 36 bits, clocked at 250 MHz. This is a double-data-rate device — data transfers on both clock edges — effectively delivering a 500 MT/s interface over a parallel 36-bit bus. It's built for the line-rate buffering and look-aside cache roles in networking gear, test equipment, and baseband processing where QDR-style read-write turnaround isn't needed but raw sequential throughput is. The 1.7V to 1.9V core supply keeps I/O power manageable at these edge rates.
At 250 MHz the part delivers a 500 MT/s data rate on a 36-bit bus, which works out to roughly 2.25 GB/s of raw bandwidth. That's enough to keep a 10 GbE MAC's packet buffer fed without stalling or to service a high-speed ADC's sample stream in real time. The DDR II interface means the address and control bus runs at the single-edge clock rate, so the controller needs a DDR-capable memory controller — not every FPGA or ASIC has one.
The 165-ball FBGA (13x15 mm) footprint is a fine-pitch BGA — ball pitch is 0.65 mm, so the PCB needs micro-via or at least a tight via-in-pad strategy for the inner rows. The supply voltage window is 1.7V to 1.9V, which is tighter than a standard 1.8V rail; a precision LDO or a DC-DC with good load regulation is recommended. Decoupling should follow the layout guidelines in the datasheet: a 0.1 µF ceramic per supply ball pair, plus a bulk 10 µF on the board.
Infineon (formerly Cypress) continues to manufacture this DDR II SRAM family, and there is no announced last-time-buy. For dual-source resilience, the part is pin-compatible with other members of the CY7C1320KV18 density and speed variants — the same 165-ball FBGA footprint and 1.7V-1.9V supply — so a speed-bin or density change doesn't force a board spin.