Asynchronous FIFO for 5 V systems
The CY7C433-20JXCT is a 36K (4K x 9) asynchronous FIFO from Infineon's CY7C series, designed for buffering data across clock domains in 5 V logic systems. Its 20 ns access time and 50 MHz data rate set the timing budget for read/write cycles in a backplane or data-acquisition front-end.
What the 20 ns access time means for the bus
With a 20 ns access time, the FIFO's data output becomes valid 20 ns after the read-enable edge — this sets the minimum read-cycle period at 20 ns plus the controller's setup time. The 50 MHz data rate ceiling means the FIFO can sustain back-to-back reads or writes at 20 ns intervals, matching the cycle time of many CPLD or FPGA interfaces in the same 5 V domain. The 4K x 9 organization stores 4096 9-bit words — the ninth bit is typically used for parity or a control flag separate from the data bus. Retransmit capability allows resetting the internal read pointer to the beginning of the FIFO without a full reset, useful for retrying a corrupted data block. The commercial temperature range (0°C to 70°C) limits it to indoor, temperature-controlled environments — no extended or industrial temp grade on this variant.
Infineon lists the CY7C433-20JXCT as Obsolete. This part is sourced through independent distribution channels; quantities are lot-specific and confirmed at RFQ. The 32-PLCC (11.43x13.97 mm) J-lead package was common for mid-2000s FIFO designs. The Tape & Reel packaging suggests original reel quantities for automated assembly, though surplus stock may arrive in cut-tape or tube as well.