72 Mbit DDR II+ SRAM at 400 MHz — bus timing and memory headroom
The CY7C1570KV18-400BZXC: It clocks at 400 MHz on the parallel interface, which means the data bus toggles at 800 Mbps per pin — the DDR II+ standard eliminates dead cycles between read and write turns, so back-to-back throughput is the real gain here, not just the clock number. The 36-bit word width (2M x 36) is a deliberate fit for systems that carry a parity or ECC lane alongside a 32-bit data bus: networking line cards, telecom framers, and high-end packet processors that need deterministic latency without DRAM refresh overhead.
That is tighter than the legacy 3.3 V synchronous SRAM generation and requires a dedicated low-noise regulator — a 1.8 V LDO or switching converter with <10 mV ripple. The supply tolerance is ±100 mV, so the PDN impedance target below 300 MHz needs to stay under about 10 mΩ to keep the rail inside spec during the 400 MHz clock's transient draw. Plan for a solid via-stitched plane under the 165-ball BGA, not a routed trace.
165-FBGA — footprint and rework considerations
The 165-ball FBGA (13x15 mm) is a fine-pitch BGA requiring a microvia-capable PCB. The Tray shipping medium is standard for this package.
That is a commercial-grade part — it belongs in a controlled indoor environment: server room, central office, lab instrument, or office networking gear.