Synchronous FIFO — 4K x 9 at 40 MHz
The Cypress CY7C4241V-25AXC is a synchronous FIFO memory from the CY7C series, organized 4K words deep by 9 bits wide for a total of 36K bits. Depth- and width-expansion capability is built in, and programmable flags are supported, but it does not offer retransmit or FWFT (First Word Fall Through) operation. The 32-TQFP package (7x7 mm) is surface-mount, intended for commercial-temperature (0°C to 70°C) equipment such as telecom line cards, network switches, and printer controllers where a moderate-depth synchronous buffer is needed.
No direct pin-compatible replacement is listed in the Cypress portfolio; the 4K x 9 synchronous FIFO architecture with 40 MHz operation at 3.3 V is a niche that newer parts in the CY7C or IDT72V series may cover with different package or timing. For ongoing production, a last-time-buy or surplus-channel procurement is the practical path.
40 MHz synchronous — bus timing and flag support
The 40 MHz clock rate and 15 ns access time mean the FIFO can sustain a back-to-back read or write every 25 ns cycle. The synchronous interface simplifies control in FPGA or ASIC designs: a single rising edge clocks data in or out, with almost-full and almost-empty flags available for flow control. Depth-expansion mode allows cascading multiple devices when 4K words are insufficient, though the lack of FWFT adds a dead cycle on the first read after a write-to-read transition — something to budget for in latency-sensitive paths.