400 MHz DDR II+ SRAM for high-throughput data paths
The Infineon CY7C1248KV18-400BZXC is a 36Mbit synchronous SRAM organized as 2M x 18, using a DDR II+ parallel interface that clocks at 400 MHz.
At 400 MHz, the DDR II+ interface transfers data on both clock edges, effectively doubling the data rate to 800 MT/s per pin. For an 18-bit bus, that translates to a raw bandwidth of 14.4 Gbit/s. The synchronous architecture eliminates the dead cycles you get with asynchronous SRAM on back-to-back reads or writes, which matters when a switch ASIC is doing table lookups every few nanoseconds. The trade-off: the 165-LBGA (13x15mm FBGA) demands careful PCB layout — tight impedance control on the data lines and a clean 1.8V supply with adequate decoupling right at the BGA pads.