The Cypress CY7C425-20VXC is a 9K (1K x 9) asynchronous FIFO memory in a 28-SOJ surface-mount package. Designed for buffering data between asynchronous clock domains, it is commonly used in telecom, networking, and data-acquisition systems where a simple, unidirectional FIFO with depth and width expansion capability is needed. The part includes retransmit capability but does not support FWFT or programmable flags.
In a system clocked at 50 MHz (20 ns period), this leaves zero margin for setup time on the receiving device — the bus timing is tight. A designer should verify the receiving device's setup-time requirement against the FIFO's access time plus any PCB trace delay. For relaxed timing, a slower data rate or a FIFO with a faster access time would be needed.
Sourcing is limited to the independent distribution market — new-old-stock, surplus, or verified broker inventory. Any replacement would require a pin-compatible FIFO from another vendor or a redesign with a newer FIFO family. For an existing BOM line, the only reliable supply path is through a qualified independent distributor who can source and verify the original Cypress die.
Package and supply — design-in notes
Maximum supply current is 55 mA. The part is unidirectional and supports depth and width expansion via external logic.