Texas Instruments CD74HC173M

Overview

CD74HC173M from Texas Instruments is a high-speed CMOS quad D-type flip-flop with three-state outputs, shared clock (CP), master reset (MR), and dual data enable (E1/E2) and output enable (OE1/OE2) controls. It operates from 2 V to 6 V, supports –55°C to 125°C industrial/military temperature range, delivers 15 LSTTL load drive capability, and features balanced propagation delay (e.g., 43 ns max at 6 V) for synchronous bus interface applications.

For engineers reviewing the CD74HC173M datasheet, CD74HC173M pinout, CD74HC173M application, or CD74HC173M equivalent, this page provides verified functional identity, SOIC-16 package mapping, truth-table–validated control logic behavior, real-world timing constraints (tSU = 15 ns min at 6 V), and confirmed drop-in alternatives for legacy bus-hold and register-transfer designs.

Technical Context

The CD74HC173M implements four independent edge-triggered D-type flip-flops sharing CP, MR, E1/E2, and OE1/OE2 signals. Its synchronous positive-edge clocking, asynchronous active-high master reset, and dual-input-enable feedback loop allow state retention without clock disruption - critical for glitch-free bus arbitration in multi-master systems.

All outputs are three-state buffered with independent OE1/OE2 control, enabling bidirectional bus driving without external logic. The device uses silicon-gate CMOS technology, achieving HC-family noise immunity (NIL/NIH = 30% of VCC at 5 V) and low ICC (≤160 µA over full temperature range).

Key Specifications

Pinout & Package

CD74HC173M is supplied in a 16-pin SOIC (D) package with nominal body size 9.90 mm × 3.90 mm, moisture sensitivity level 1 (260°C reflow), and NiPdAu lead finish. Pin 1 index area located at top-left corner per JEDEC MO-153.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad D-type flip-flop applications.

Compared with CD74HC173M, CD74HC173M96.A offers identical performance in optimized tape-and-reel form for SMT lines, while SN74HC173N provides pin-compatible through-hole implementation at the cost of larger board area and higher thermal resistance - making CD74HC173M the optimal choice for new compact, surface-mount designs requiring military-grade temperature support.

Availability

CD74HC173M is available at Aetrix Electronics and suitable for industrial PLC expansion, military data bus interface, automated test equipment pattern generation, and legacy controller upgrades requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD74HC173M includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a U.S.-based semiconductor manufacturer founded in 1930, specializing in analog, embedded processing, and logic solutions with broad industrial, automotive, and defense certifications.

CD74HC173M belongs to TI's legacy HC logic portfolio designed for high-reliability, wide-temperature-range digital interfacing - specifically targeting bus-oriented systems requiring deterministic timing, low power, and proven long-term availability.

FAQ

What is the maximum clock frequency supported by CD74HC173M?

The CD74HC173M supports a maximum clock frequency of 24 MHz at VCC = 6 V and TA = –55°C to 125°C per switching characteristics tables. At 5 V and 25°C, typical fMAX reaches 60 MHz, but design margins require derating to 24 MHz for full temperature compliance. This makes CD74HC173M suitable for synchronous control applications below 25 MHz in harsh environments.

Does CD74HC173M support 3.3 V operation?

Yes, CD74HC173M fully supports 3.3 V operation within its specified 2 V to 6 V supply range. At VCC = 3.3 V, it maintains guaranteed VOH ≥ 3.15 V and VOL ≤ 0.1 V under CMOS loads, and meets all timing parameters including tpd ≤ 51 ns (max) and tSU ≥ 15 ns (min), enabling direct interfacing with 3.3 V microcontrollers without level translation.

How does the dual output enable (OE1/OE2) function in CD74HC173M?

In CD74HC173M, OE1 and OE2 are OR-connected active-high signals: asserting either forces all Q0–Q3 outputs into high-impedance state. This architecture allows flexible bus control - for example, OE1 can manage primary bus access while OE2 serves as emergency disable during fault conditions, both without affecting internal flip-flop states or clock operation.

Is CD74HC173M pin-compatible with the older 74LS173?

No, CD74HC173M is not pin-compatible with 74LS173. While both are quad D-type flip-flops, the 74LS173 uses different pin assignments for enables and outputs. However, CD74HCT173M - the TTL-compatible variant - is functionally and pin-compatible with 74LS173, offering identical logic thresholds and drive strength for true drop-in replacement in legacy LS-based designs.

What is the purpose of the dual data enable inputs (E1 and E2) in CD74HC173M?

E1 and E2 are active-low inputs that gate data flow into the D-flip-flops. When both are low, D0–D3 pass through to the registers on CP rising edges. If either is high, the corresponding Q outputs are fed back to D inputs, holding current state - allowing selective freeze of register contents without halting the system clock, which is essential for glitch-free bus handshaking and state machine synchronization.