Texas Instruments SN74HC174NG4

Overview

SN74HC174NG4 from Texas Instruments is a hex D-type positive-edge-triggered flip-flop with shared clock and asynchronous clear, operating from 2 V to 6 V, delivering 14 ns typical propagation delay, ±4-mA output drive at 5 V, and low 80-μA max ICC-used in synchronous data latching and register staging within industrial control logic and digital instrumentation.

For engineers reviewing the SN74HC174NG4 datasheet, SN74HC174NG4 pinout, SN74HC174NG4 application, or SN74HC174NG4 equivalent, this page delivers verified functional behavior, PDIP-16 package mapping, timing constraints (tsu = 25 ns @ 6 V), absolute maximum ratings, and validated alternatives for register-level design reuse and BOM optimization.

Technical Context

The SN74HC174NG4 implements six independent D-type latches sharing a common CLK and active-low CLR input, each triggered on the rising edge of CLK while ignoring D input changes during stable CLK states. Its CMOS architecture ensures rail-to-rail output swing and high noise immunity across the full 2–6 V supply range.

It supports TTL-compatible input thresholds (VIH = 4.2 V, VIL = 1.8 V @ VCC = 6 V), drives up to 10 LSTTL loads, and maintains defined logic states under slow or floating inputs only when unused pins are tied to VCC or GND per TI SCBA004 guidance.

Key Specifications

Pinout & Package

SN74HC174NG4 is supplied in a 16-pin plastic dual in-line package (PDIP), 19.31 mm × 6.35 mm body size, through-hole mountable with 2.54 mm pitch, rated for −40°C to +85°C operation and RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC174NG4, SN74HC175N offers granular reset control at the cost of reduced channel count per package, while CD74HC174E provides identical functionality with established qualification history-making it ideal for drop-in replacement in long-lifecycle instrumentation designs.

Availability

SN74HC174NG4 is available at Aetrix Electronics and suitable for industrial control panels, digital test equipment, and embedded instrumentation requiring stable component supply, long-term obsolescence management, and RoHS-compliant through-hole logic ICs.

Supply support for SN74HC174NG4 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 50 years of innovation in high-reliability digital ICs.

The SN74HC174NG4 belongs to the 74HC logic family, designed for low-power, high-speed CMOS operation in industrial, automotive, and communications systems requiring robust noise immunity and wide supply tolerance.

FAQ

What is the maximum clock frequency supported by SN74HC174NG4?

The SN74HC174NG4 supports a maximum clock frequency of 29 MHz at VCC = 6 V, derived from its 34 ns maximum propagation delay (tpd) and timing constraints. This value assumes CL = 50 pF load and operation within recommended conditions; derating is required for higher temperatures or heavier capacitive loads. The SN74HC174NG4 datasheet specifies fmax = 29 MHz under these conditions.

Does SN74HC174NG4 include complementary (Q̅) outputs?

No, the SN74HC174NG4 provides only true (Q) outputs for each of its six D-type flip-flops-there are no dedicated inverted (Q̅) outputs. If complemented signals are required, external inverters or logic gates must be added. This design choice reduces pin count and simplifies layout for applications where only non-inverted latched data is needed.

Can unused inputs on SN74HC174NG4 be left floating?

No, all unused inputs on SN74HC174NG4-including D inputs not connected to data sources-must be tied to either VCC or GND to prevent undefined logic states and excessive current draw. TI's application report SCBA004 explicitly mandates this practice for HC-series devices to ensure stable operation and avoid increased ICC or oscillation.

What is the purpose of the CLR pin on SN74HC174NG4?

The CLR (clear) pin on SN74HC174NG4 is an asynchronous, active-low input that forces all six Q outputs low immediately-regardless of CLK state or D input values. It is commonly used for system initialization, error recovery, or forced register reset without waiting for a clock edge, making SN74HC174NG4 suitable for safety-critical or deterministic startup sequences.

Is SN74HC174NG4 compatible with 3.3 V logic systems?

Yes, SN74HC174NG4 operates reliably from 2 V to 6 V, including standard 3.3 V supply rails. At VCC = 3.3 V, it maintains valid VIH (≥2.31 V) and VIL (≤1.09 V) thresholds, delivers ~±3 mA output drive, and achieves ~18 ns typical tpd-enabling direct interfacing with 3.3 V microcontrollers and FPGAs without level-shifting circuitry.