15 ns access time — the timing margin that decides fit
The Texas Instruments SN74ACT7201LA15RJR is an asynchronous FIFO memory organized 512 words by 9 bits, giving 4.5 Kbit of storage. Its 15 ns access time is the spec that determines whether this part can buffer data between a fast processor and a slower peripheral without inserting wait states — at 40 MHz data rate, the read/write cycle window is tight enough that a slower FIFO would stall the bus.
Asynchronous operation and expansion options
This FIFO operates asynchronously — no external clock is needed for read/write handshaking, which simplifies the interface but means the designer must manage the flag logic externally since programmable flags are not supported. Expansion in both depth and width is possible by cascading multiple devices, and the retransmit capability allows rereading data without a full reset, useful in retry protocols. The 125 mA maximum supply current gives a rough power budget for the 5 V rail.
Package and handling — 32-PLCC in Bulk
Housed in a 32-lead PLCC (J-Lead) package, surface-mount only. The Bulk shipping form means the parts come loose in a bag or tube, not on a reel — plan for manual placement or vibratory feeder if using automated assembly.
No official successor or second-source alternate is listed by Texas Instruments, but the 74ACT family has broad functional compatibility across vendors.