Texas Instruments CD74HCT174M

Overview

CD74HCT174M from Texas Instruments is a hex D-type flip-flop with asynchronous common reset, implemented in silicon-gate CMOS technology for TTL-compatible operation at 4.5V–5.5V. It features positive-edge-triggered clock, six master-slave stages, -55°C to +125°C operating range, and drives up to 10 LSTTL loads. It serves as a synchronous data latch in digital control logic, state machines, and register file interfaces.

For engineers reviewing the CD74HCT174M datasheet, CD74HCT174M pinout, CD74HCT174M application, or CD74HCT174M equivalent, key selection criteria include its HCT-level input compatibility (VIH ≥ 2.0 V, VIL ≤ 0.8 V), 25 MHz max clock frequency at 5V, 40 ns typical propagation delay (CP to Q), and SOIC-16 package suitability for high-reliability industrial timing and control circuits.

Technical Context

The CD74HCT174M implements six independent D-type flip-flops sharing a single buffered clock (CP) and a common asynchronous master reset (MR). Each stage transfers Dn to Qn on the low-to-high transition of CP, provided setup (16 ns min) and hold (5 ns min) times are met.

Its HCT logic family ensures direct interface with standard LS-TTL outputs without level shifting, while maintaining CMOS advantages: low static current (≤160 µA over full temperature range), high noise immunity (NIL/NIH = 30% of VCC), and rail-to-rail output swing under TTL load conditions.

Key Specifications

Pinout & Package

CD74HCT174M is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package, surface-mount compatible with JEDEC MS-012AC, body width 3.9 mm, lead pitch 1.27 mm, and moisture sensitivity level (MSL) Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT174N and CD74HC174M, the CD74HCT174M uniquely combines SOIC-16 surface-mount compatibility, guaranteed LSTTL input compatibility, and extended temperature qualification - making it optimal for new industrial and aerospace designs requiring high-density, high-reliability register storage.

Availability

CD74HCT174M is available at Aetrix Electronics and suitable for industrial PLC register files, automotive body control modules, and avionics discrete input buffering requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HCT174M 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power management, and signal chain technologies.

The CD74HCT174M belongs to TI's High-Speed CMOS Logic (HCT) product line, engineered specifically for drop-in replacement of legacy 74LS174 in industrial, military, and aerospace systems demanding TTL compatibility, wide temperature operation, and low power.

FAQ

What is the maximum clock frequency supported by the CD74HCT174M?

The CD74HCT174M supports a maximum clock frequency of 25 MHz at VCC = 5V over the full -55°C to +125°C operating range. This value is specified in the "Prerequisite For Switching Function" table of the official datasheet (SCHS159C), with derating to 20 MHz at +85°C and 17 MHz at +125°C. The CD74HCT174M achieves this performance while maintaining guaranteed setup (20 ns min) and hold (5 ns min) timing margins.

Does the CD74HCT174M require external pull-up or pull-down resistors on its inputs?

No, the CD74HCT174M does not require external pull-up or pull-down resistors on its inputs. Its CMOS input structure exhibits ≤1 µA leakage current (II), and its TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) ensure stable logic levels when driven by standard LS-TTL or microcontroller GPIOs. Unused inputs should still be tied to VCC or GND to prevent floating nodes and unintended current draw.

Can the CD74HCT174M operate at 3.3V supply voltage?

No, the CD74HCT174M is not rated for 3.3V operation. Its HCT family specification mandates a supply voltage range of 4.5V to 5.5V only. Attempting to power the CD74HCT174M at 3.3V will result in undefined logic behavior, failure to recognize TTL input levels, and potential violation of absolute maximum ratings. For 3.3V systems, consider the CD74HC174M or SN74LVC174A instead.

What is the purpose of the MR (Master Reset) pin on the CD74HCT174M?

MR is an asynchronous active-low master reset input that forces all six Q outputs (Q0–Q5) to logic low immediately, independent of the clock signal. When MR is held low, the CD74HCT174M ignores CP transitions and maintains Qn = L. This function enables deterministic system initialization, error recovery, and safe power-up sequencing - critical in safety-critical and real-time control applications.

Is the CD74HCT174M pin-compatible with the 74LS174?

Yes, the CD74HCT174M is functionally and pin-compatible with the 74LS174, as explicitly stated in the datasheet: "The 'HCT174 is functional as well as, pin compatible to the 'LS174." This includes identical pin assignments (MR, D0–D5, Q0–Q5, CP, VCC, GND), same truth table behavior, and matching timing parameters under 5V operation - enabling direct replacement without PCB modification.