72 Mbit QDR II at 375 MHz — what this SRAM was built for
The CY7C1563V18-375BZC: It clocks at 375 MHz on a parallel interface, which places it squarely in high-throughput networking gear — switches, routers, and line cards that need back-to-back read-write throughput without dead cycles between bus turns. The QDR II (Quad Data Rate) scheme delivers separate read and write ports, so the bus never stalls on turnaround; that matters when the packet buffer needs to sustain line-rate traffic through a lookup table or statistics counter bank. The supply rail runs at 1.7V to 1.9V, a core voltage that aligns with the sub-2V I/O standards common on ASICs and FPGAs from the same era. The 165-FBGA (15x17 mm) footprint requires a controlled-impedance layout on the address and data lines; the BGA pitch dictates micro-vias or blind vias in a multilayer board.
Obsolete — sourcing reality and the replacement question
There is no listed official successor in the available records. The 165-FBGA footprint and 375 MHz speed bin narrow the cross-ship options considerably; a direct drop-in replacement would need to match the 72 Mbit density, QDR II interface, and same package ball-out, which is a narrow search even in the QDR II family.
Package and mounting — FBGA handling notes
The device ships in a 165-ball FBGA (15x17 mm). The BGA pitch (likely 1.0 mm or 0.8 mm) requires X-ray inspection after reflow to catch hidden solder-joint opens or shorts under the package body. No moisture sensitivity level is stated in the available record, but a standard bake-out before reflow is prudent if the storage history is unknown.