550 MHz DDR II+ SRAM — the throughput story
The CY7C25682KV18-550BZXI is a 72 Mbit synchronous SRAM from Infineon, organized 4M x 18 and clocked at 550 MHz on a DDR II+ interface. That clock rate means the data bus toggles on both edges, so the effective data rate per pin is 1.1 Gbps — the limiting factor in a high-throughput pipeline is often the controller's own timing closure, not the memory's access window. The 1.7 V to 1.9 V core supply puts it in the low-voltage SRAM class — the narrower rail tolerance (200 mV window) demands a clean local regulator with <10 mV ripple at the BGA balls; a shared 1.8 V rail from a switching converter without post-filtering will push the core out of spec under load transients.
Package and board-fit — 165-ball FBGA
Housed in a 165-ball FBGA measuring 13x15 mm (supplier device package 165-FBGA). The 0.80 mm ball pitch is standard for this density — a 4-layer PCB with via-in-pad or microvias under the BGA is the practical minimum for fan-out. The package is surface-mount only, shipped in trays. The 550 MHz clock at the hot end (85°C) still meets the timing window — the derating curve is in the datasheet's AC timing table, not the DC specs.
That means it is still a valid choice for new designs and production builds without an imminent obsolescence risk.