72 Mbit QDR IV — bandwidth ceiling for the data plane
The CY7C4042KV13-933FCXC: This is a 72 Mbit synchronous SRAM organized 2M x 36, using the QDR IV architecture — a double-data-rate interface that transfers data on both clock edges, delivering a peak bandwidth of 933 MHz x 36 bits per edge. The 36-bit data bus width suits systems that need a 72-bit ECC word (two devices) or a single 36-bit datapath without parity overhead.
933 MHz clock — signal-integrity budget
At 933 MHz the parallel interface demands controlled-impedance routing, matched trace lengths, and a low-inductance decoupling network within the 361-FCBGA (21x21 mm) footprint. The supply rail tolerance is tight — 1.26 V to 1.34 V — so the board regulator must hold regulation within 40 mV under the transient load of the QDR IV I/O bank.