Synchronous FIFO at 66.7 MHz — 4.5 Kbit buffer for rate-matching and data staging
The Infineon CY7C4211V-15AXI is a synchronous FIFO memory from the CY7C family, organized as 512 words by 9 bits wide for a total of 4.5 Kbit. The 9-bit width accommodates an eighth data bit or a parity/control flag alongside the byte-wide data path, which is typical for telecom frame buffers, DSP data staging, or PCI bus-rate matching where the extra bit carries sideband information.
66.7 MHz clock and 10 ns access — timing margin for synchronous buses
At 66.7 MHz the clock period is 15 ns, so the 10 ns access leaves 5 ns of setup margin before the next clock edge — enough for most 3.3 V logic families without adding pipeline stages. If the receiving device has a tighter setup requirement, the 10 ns access still gives headroom for board trace delay and fan-out loading. The synchronous architecture eliminates the dead cycles associated with asynchronous FIFOs on read-to-write turnaround, which matters when the FIFO sits between two clock domains running at the same nominal frequency but with phase drift.
Depth and width expansion — daisy-chain for larger buffers
The CY7C4211V-15AXI supports expansion in both depth and width. Depth expansion chains multiple devices by cascading the full-flag and read-enable signals, building a larger FIFO without external logic — useful when 512 words is insufficient for a packet buffer or line accumulator. Width expansion pairs two or more devices with the same clock and control signals to create a wider data path (e.g., 18 bits from two 9-bit parts). The retransmit capability allows the FIFO to re-read data from the beginning without a full reset, which is handy for protocol retry buffers or test-pattern loops. Note that programmable flags and first-word fall-through (FWFT) are not supported, so the empty/full flags are fixed at the boundary states — the host must poll or interrupt on these boundaries rather than set custom thresholds.
The CY7C4211V-15AXI is listed as Obsolete. No official replacement part number is recorded in the lifecycle data, so there is no direct pin-compatible successor from Infineon or Cypress. For a repair or a last-time-build run, the CY7C4211V-15AXI remains available on the spot market while inventory lasts.