Synchronous FIFO for bus-rate matching and data buffering
The Cypress CY7C4221-15JXC is a synchronous FIFO memory from the CY7C series, organized as 1K x 9 bits (9 Kbit total). The 9-bit width accommodates an eighth data bit plus a parity or control bit, common in telecom and networking equipment.
The CY7C4221-15JXC is marked obsolete by Cypress (now Infineon). For production or repair requirements, this part must be sourced through the surplus and broker channel.
The 66.7 MHz clock rate sets the maximum write/read cycle frequency. The 35 mA maximum supply current is modest for a 5 V FIFO of this speed.
1K x 9 depth and programmable flags
The 1K x 9 organization provides 1024 words of storage, each 9 bits wide. The part supports programmable flags (almost-full, almost-empty) via the flag-programming pins, allowing the designer to set threshold levels that trigger flow-control logic. Depth and width expansion are supported, so multiple devices can be cascaded for larger buffers. It does not support First-Word Fall-Through (FWFT) operation.
32-PLCC (J-Lead) footprint and temperature grade
The 32-PLCC package (J-Lead, 11.43 x 13.97 mm body) is a surface-mount footprint with leads formed under the package — it requires a PLCC socket or a reflow profile compatible with J-lead soldering.