18 Mbit DDR II SRAM at 250 MHz — what the clock rate buys you
The CY7C1320CV18-250BZXC is a Cypress 18 Mbit synchronous SRAM using DDR II architecture, organized as 512K words by 36 bits. The 250 MHz clock rate delivers double-data-rate transfers on each clock edge, giving an effective 500 MHz data rate on the 36-bit bus. The parallel memory interface keeps latency deterministic — no serialisation overhead. Supply range of 1.7V to 1.9V ties it to a 1.8V core rail, common in ASIC and FPGA designs of that era.
165-ball FBGA — footprint and rework notes
The ball pitch is tight enough that breakout vias need to be planned early in the stack-up. Surface-mount only, no through-hole option.
Production has ended; the only channel for procurement is the surplus and independent distribution market. Date-code spreads and reel condition will vary — sealed factory reels with consistent date-codes are the preferred lot condition. For a new design, a current-production DDR II or QDR SRAM in a similar density and package should be evaluated.