Last-time-buy reality for the 72 Mbit DDR II+ SRAM
The CY7C1568KV18-550BZXI: No official successor or pin-compatible replacement is listed by Infineon.
What the 550 MHz clock means for your memory controller
At 550 MHz, this DDR II+ SRAM delivers a peak data rate of 1.1 G transfers per second per I/O pin (double data rate). The parallel interface expects the controller to match the QDR-style read/write timing — the 4M x 18 organization provides 18-bit-wide data words, so the controller must handle the 72 Mbit density across the full address range.
165-FBGA footprint and supply rails
Decoupling should follow the QDR-II+ layout guidelines: one 0.1 µF per supply ball pair, placed within 2 mm of the ball, plus bulk capacitance on the board side.
Temperature grade and environment
This covers most outdoor telecom, base-station, and industrial controller environments. The volatile nature of SRAM means data is lost at power-down — no non-volatile retention.