64-bit bipolar TTL SRAM — 8.5 ns access time
The 54F189DC is a 64-bit bipolar TTL SRAM from the 54F series, organized as 16 words by 4 bits. Its 8.5 ns access time makes it one of the faster small SRAMs from the TTL era, suited for cache tag stores, writable control store, or high-speed scratchpad in legacy TTL-based systems. The 4.5 V supply rail is a reminder this is a bipolar part — it won't run on a 3.3 V or 5.0 V CMOS supply without level shifting.
16 x 4 organization — what it fits
With only 64 bits total, the 54F189DC is not a code-storage memory. Its natural home is as a register file for a 4-bit datapath, a FIFO buffer for a narrow bus, or a look-up table for a state machine. The parallel interface keeps the pin count low — 16 pins in a through-hole package — and the write cycle time of 15.5 ns means back-to-back writes are possible at over 64 MHz.
Through-hole package and temperature grade
The part comes in a through-hole package (Bulk shipping form), which means it's designed for socketed or wave-soldered boards — not for high-density SMT reflow. No extended temp or automotive qualification is listed.
That said, this is a legacy bipolar TTL part, not a mainstream CMOS memory.