Texas Instruments SN74HC174D

Overview

SN74HC174D from Texas Instruments is a hex D-type positive-edge-triggered flip-flop IC with shared clock (CLK) and asynchronous clear (CLR) inputs, operating from 2 V to 6 V supply, delivering 14 ns typical propagation delay at 5 V, ±4 mA output drive, and low 80 μA max ICC - used in synchronous data latching and register staging within digital control logic.

For engineers reviewing the SN74HC174D datasheet, SN74HC174D pinout, SN74HC174D application, or SN74HC174D equivalent, this page provides verified functional behavior, SOIC-16 package interface details, timing constraints for edge-triggered storage, and validated alternatives for register-level logic replacement.

Technical Context

The SN74HC174D implements six independent D-type latches sharing one global CLK and one active-low CLR signal; each flip-flop captures D-input state on the rising edge of CLK while CLR forces Q outputs low regardless of clock or data. It uses standard CMOS silicon process with Schmitt-trigger input thresholds not specified - all inputs require defined logic levels per VIH/VIL tables.

Timing is governed by setup time (tsu = 25 ns min at 4.5 V), hold time (th = 0 ns), and pulse width requirements (tw ≥ 20 ns for CLK/CLR at 4.5 V); propagation delay tpd ranges from 14 ns (typ) to 41 ns (max) depending on VCC and load, with CL = 50 pF.

Key Specifications

Pinout & Package

SN74HC174D is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package measuring 9.90 mm × 3.90 mm, with standard 1.27 mm lead pitch and gull-wing surface-mount terminals.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC174N and SN74HC174DBR, the SN74HC174D offers the optimal balance of manufacturability (standard SOIC reflow profile), thermal performance (RθJA = 73 °C/W), and compatibility with automated assembly - making it the default choice for new industrial PCB designs requiring six-bit synchronous storage.

Availability

SN74HC174D is available at Aetrix Electronics and suitable for industrial control registers, digital pattern generators, buffer/storage registers, and shift register stages requiring stable component supply and long-term production continuity.

Supply support for SN74HC174D 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 company specializing in analog and logic ICs, with over 50 years of leadership in industrial-grade logic families.

The SN74HC174D belongs to the 74HC high-speed CMOS logic series, designed specifically for robust, low-power, pin-compatible upgrades to legacy TTL register functions in embedded control and instrumentation systems.

FAQ

What is the maximum clock frequency supported by SN74HC174D?

The SN74HC174D supports up to 25 MHz maximum clock frequency at VCC = 4.5 V and TA = 25 °C, based on guaranteed timing parameters including minimum pulse width (20 ns) and setup time (25 ns). At VCC = 6 V, fmax increases to 29 MHz under identical conditions. System-level margin should account for temperature, voltage variation, and PCB trace loading.

Does SN74HC174D have complementary (Q̅) outputs?

No, the SN74HC174D provides only true (Q) outputs on pins 9–14; it does not include inverted (Q̅) outputs. Each of the six flip-flops delivers a single buffered Q signal. If complemented outputs are required, external inverters or dual-output variants like SN74HC175 must be used.

Can SN74HC174D operate reliably at 3.3 V supply?

Yes, SN74HC174D is fully specified for operation at 3.3 V: VIH = 2.31 V min and VIL = 1.09 V max per recommended conditions, and tpd = 27 ns max at 3.3 V ensures timing compliance in mixed-voltage 3.3 V/5 V systems without level translation.

What is the purpose of the CLR pin on SN74HC174D?

The CLR (pin 1) is an asynchronous active-low clear input that forces all six Q outputs low immediately, overriding clock and data inputs. It operates independently of CLK timing and remains effective even when CLK is static - essential for system initialization and fault recovery in safety-critical logic.

Is SN74HC174D RoHS compliant and lead-free?

Yes, SN74HC174D (orderable as SN74HC174DRG4.A) is RoHS compliant with NiPdAu (NIPDAU) lead finish and meets JEDEC Level-1 moisture sensitivity rating. Its packaging complies with IPC/JEDEC J-STD-020 standards for lead-free reflow processing at peak temperatures up to 260 °C.