SN54173, SN54LS173A, SN74173, SN74LS173A 4-bit D-type registers with 3-state outputs. 3-state outputs can directly interface with the system bus. Gated output control lines can be used to enable or disable the outputs. The completely independent clock virtually eliminates the restrictions for operating in one of two modes: parallel load or do nothing (hold). For application as bus buffer registers. Plastic small-outline (D) packages, ceramic flat (W) packages, ceramic chip carriers (FK) and standard plastic (N) and ceramic (J) DIPs are packaging options.
The document describes four models of 4-bit D-type flip-flop registers with totem-pole 3-state outputs. These devices are designed for use in bus-organized systems, allowing up to 128 outputs (SN74 series) or 49 outputs (SN54 series) to be connected to a common bus while driving standard TTL loads without additional interface components.
The datasheet provides detailed specifications including absolute maximum ratings, recommended operating conditions, and electrical characteristics for both military-grade (SN54) and commercial-grade (SN74) variants. It includes function tables, logic diagrams, pin configurations for various packages (D, J, N, W), and switching/timing parameters.
| Operating Temperature (Military) | -55°C to 125°C |
|---|---|
| Operating Temperature (Commercial) | 0°C to 70°C |
| Maximum Clock Frequency (SN74) | 25 MHz |
The SN54173 and SN54LS173A are characterized for operation over the full military temperature range of -55°C to 125°C.
The SN74173 and SN74LS173A are characterized for operation from 0°C to 70°C.