Synchronous FIFO in a 32-PLCC footprint
The CY7C4231-15JXCT is a synchronous FIFO from the CY7C series, organized as 18K (2K x 9) and clocked at 66.7 MHz with a 10 ns access time.
66.7 MHz clock and 10 ns access — the timing budget
A 66.7 MHz data rate with 10 ns access time means the FIFO can sustain one read or write per clock cycle at full speed — the access time is the window the controller must respect for the first word after a read request. At 66.7 MHz the cycle time is 15 ns, so the 10 ns access leaves 5 ns of setup margin for the downstream logic, assuming zero board delay. The 2K x 9 organization (18 Kbit) provides 2,048 words of 9 bits each — the ninth bit is often used as a parity or data-type flag in networking and telecom buffers. Depth and width expansion are supported, so multiple devices can cascade for larger buffers without external glue logic.
Infineon lists the CY7C4231-15JXCT as Obsolete.