72Mbit DDR II+ SRAM at 550 MHz — what this part is
The Cypress CY7C1568KV18-550BZXC is a 72Mbit synchronous SRAM using a DDR II+ architecture, organized as 4M x 18. It clocks at 550 MHz, which gives it the bandwidth to serve as a high-speed data buffer in network switches, test instrumentation, and telecom line cards where read-write turnaround must be minimized.
A 550 MHz clock rate on a DDR II+ SRAM means data is transferred on both edges, so the effective data rate is double the clock. For a 4M x 18 part, that translates to a peak bandwidth of about 1.98 GB/s (550 MHz × 2 edges × 18 bits ÷ 8). That throughput matters when the memory sits between a high-speed ASIC and a backplane — you avoid dead cycles on the bus that a slower QDR or NoBL part would introduce.
Cypress (now part of Infineon) no longer manufactures the CY7C1568KV18-550BZXC. The supply channel for this part is surplus and broker inventory — sealed reels with consistent date-codes are the preferred lot condition.
165-FBGA footprint and temperature grade
The package is a 165-ball FBGA, 13x15 mm body, surface-mount only. The 1.7V to 1.9V supply rail is tighter than the older 2.5V QDR parts, so the PCB power distribution needs a clean 1.8V rail with adequate decoupling.