18 Mbit DDR II+ SRAM at 250 MHz — what it is
The CY7C1320KV18-250BZC from Infineon (formerly Cypress) is a 18 Mbit synchronous SRAM using a DDR II+ (Double Data Rate) architecture, organized as 512K words by 36 bits. It clocks at 250 MHz, delivering two data transfers per clock cycle for an effective bandwidth of 18 Gbit/s on a 36-bit bus. This part targets high-throughput, low-latency applications such as network packet buffers, telecom line cards, and high-end test equipment where QDR-style read-write concurrency is not required but raw sequential bandwidth is.
The 250 MHz clock frequency is the core timing spec. Because this is a DDR II device, data is clocked on both edges, so the effective data rate is 500 MT/s per pin. With a 36-bit data bus, that yields a peak throughput of 18 Gbit/s (2.25 GB/s). That bandwidth matters when the memory is feeding a high-speed ASIC or FPGA that cannot stall on read data. The trade-off: tighter PCB layout rules for signal integrity at these edge rates — the 165-ball FBGA helps keep trace lengths short.
The board must have a dedicated 1.8 V rail with tight regulation (within 100 mV). If your existing design runs on 2.5 V I/O, this part will not drop in without a level-shifter or a separate regulator. Check your power tree before committing the BOM line.
Housed in a 165-ball LBGA (13x15 mm FBGA), this is a fine-pitch BGA — ball pitch typical for this density. The footprint requires a multi-layer PCB with microvias or blind vias for fanout.
Lifecycle — officially obsolete
Infineon lists the CY7C1320KV18-250BZC as Obsolete. No last-time-buy window remains open through the manufacturer. For existing production, the only supply channel is the independent distribution market — new-old-stock or surplus inventory.