The Infineon (Cypress) CY7C1265KV18-400BZXC is a 36 Mbit synchronous QDR II+ SRAM organized as 1M x 36, clocked at 400 MHz. The part comes in a 165-LBGA (13x15 mm) package for surface-mount assembly. QDR II+ architecture delivers separate read and write data ports, eliminating the bus-turnaround dead cycles that conventional SRAMs incur. At 400 MHz the part sustains back-to-back read and write transactions at full clock rate — the kind of throughput a network line card or high-end telecom buffer demands.
The 400 MHz clock rate translates to a 2.5 ns cycle time. On a QDR II+ bus, each clock edge can launch a data transfer, so the effective data rate per pin is 800 Mbps (double-data-rate on both read and write ports). That bandwidth is what makes this part a fit for packet buffers and lookup tables in 10 GbE and OTN equipment where the SRAM must keep up with the line rate without inserting wait states.
Temperature grade: indoor equipment only
This SRAM belongs in a climate-controlled rack, not an outdoor cabinet or an engine bay. If the board sees -40°C or +85°C, this part will not meet the operating spec.
Lifecycle reality: obsolete, sourced through independent channels
Infineon lists this part as obsolete. No factory lead time applies; the part is sourced from inventory held by distributors and brokers who carry legacy Cypress SRAM.