Texas Instruments CD74HCT173M

Overview

CD74HCT173M 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 at 4.5 V to 5.5 V, delivers 60 MHz max clock frequency at 5 V, supports –55°C to +125°C industrial/military temperature range, and drives up to 15 LSTTL loads - used in synchronous bus interface and data latching applications.

For engineers reviewing the CD74HCT173M datasheet, CD74HCT173M pinout, CD74HCT173M application, or CD74HCT173M equivalent, this page provides verified functional identity, SOIC-16 package mapping, propagation delay (17 ns typ @ 5 V), three-state timing behavior, and direct LSTTL-compatible input thresholds (VIL ≤ 0.8 V, VIH ≥ 2.0 V) critical for bus arbitration and level-shifted control logic design.

Technical Context

The CD74HCT173M implements four edge-triggered D-type flip-flops sharing CP, MR, E1/E2, and OE1/OE2 control lines. Its HCT logic family ensures TTL-level input compatibility while maintaining CMOS power efficiency and noise immunity (NIL/NIH = 30% of VCC).

Three-state outputs are independently controlled by OE1 and OE2: either high forces all Qx into high-impedance mode regardless of CP or MR state. Input enables E1/E2 gate data flow - when either is high, Q outputs feed back to D inputs, holding state without clock interruption.

Key Specifications

Pinout & Package

CD74HCT173M is housed in a 16-pin SOIC (D) package measuring 9.90 mm × 3.90 mm with 1.27 mm lead pitch and moisture sensitivity level 1 (260°C reflow compatible).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT173N and CD74HC173M, CD74HCT173M uniquely combines 5 V TTL input compatibility, SOIC-16 surface-mount footprint, and 15-LSTTL drive in a single military-temperature-rated device - making it optimal for high-reliability embedded bus interfaces where pin compatibility and bus drive strength are non-negotiable.

Availability

CD74HCT173M is available at Aetrix Electronics and suitable for industrial PLC I/O register design, avionics data acquisition buffering, and military communication sync logic requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HCT173M 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 global semiconductor leader specializing in analog, embedded processing, and logic solutions with over 90 years of innovation in high-reliability IC design.

CD74HCT173M belongs to TI's CD74HCT logic family - engineered for seamless integration into legacy TTL-based systems requiring CMOS power efficiency, robust noise immunity, and extended temperature operation.

FAQ

What is the maximum clock frequency supported by CD74HCT173M?

The CD74HCT173M supports a maximum clock frequency of 60 MHz at VCC = 5 V with CL = 15 pF, as specified in the switching characteristics table. This value is measured under typical conditions and remains valid across the full –55°C to +125°C operating range, though actual achievable frequency may decrease slightly at temperature extremes due to increased propagation delay (50 ns max at –55°C).

Does CD74HCT173M require external pull-up resistors on its output enable pins?

No, CD74HCT173M does not require external pull-up resistors on OE1 or OE2. These inputs are CMOS-compatible with rail-to-rail voltage thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V at 5 V), and internal circuitry ensures defined logic states even with clean digital drive. Pull-ups are unnecessary unless interfacing with open-drain controllers or implementing wired-OR logic - which is not a standard use case for CD74HCT173M.

Can CD74HCT173M operate reliably at 3.3 V supply voltage?

No, CD74HCT173M is not rated for 3.3 V operation. Its recommended operating voltage range is strictly 4.5 V to 5.5 V, as defined in the HCT family specification. At 3.3 V, input thresholds (VIH ≥ 2.0 V) become marginal, output drive collapses, and timing parameters fall outside datasheet guarantees. For 3.3 V systems, consider CD74HC173M instead.

How does the master reset (MR) function interact with output enable (OE1/OE2) in CD74HCT173M?

In CD74HCT173M, MR is asynchronous and overrides all other controls: when MR = high, all Q outputs force low immediately, regardless of OE1/OE2 state or clock edge. OE1/OE2 only affect output impedance - they do not block MR's ability to assert Q = low. This ensures deterministic reset behavior even when outputs are disabled for bus isolation.

Is CD74HCT173M pin-compatible with older 74LS173 devices?

Yes, CD74HCT173M is functionally and pin-compatible with 74LS173, sharing identical pin assignments for D0–D3, Q0–Q3, CP, MR, E1, E2, OE1, OE2, VCC, and GND in the 16-pin SOIC package. However, CD74HCT173M draws significantly less supply current and offers improved noise immunity, making it a direct drop-in replacement in most 5 V TTL systems without layout changes.