Texas Instruments SN74HCT374PW

Overview

SN74HCT374PW from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state outputs, operating at 4.5 V–5.5 V supply voltage, delivering ±6-mA output drive at 5 V, featuring 22-ns typical propagation delay (tpd), and supporting bus-hold-free I/O port buffering in industrial control backplanes.

For engineers reviewing the SN74HCT374PW datasheet, SN74HCT374PW pinout, SN74HCT374PW application, or SN74HCT374PW equivalent, this device serves as a TTL-compatible, high-drive, low-power latched buffer for bidirectional data buses requiring precise clock-edge sampling and high-impedance isolation during bus arbitration.

Technical Context

The SN74HCT374PW implements eight independent D-type flip-flops synchronized to the rising edge of CLK, with asynchronous output-enable (OE) control that places all Q outputs in high-impedance state without affecting internal latch states. Its TTL-compatible inputs accept 0.8 V/2.0 V thresholds across 4.5–5.5 V VCC.

Each flip-flop drives up to 15 LSTTL loads with ±6-mA output current capability, while maintaining low ICC (≤80 μA max) and input leakage ≤1 μA. Timing is characterized at CL = 50 pF and CL = 150 pF, with tpd = 41 ns (max, 5.5 V, CL = 150 pF) and tsu = 23 ns (min, 5.5 V).

Key Specifications

Pinout & Package

TSSOP-20 package (6.50 mm × 4.40 mm, 1.2 mm max height), JEDEC MO-153 compliant, with exposed pad not electrically connected. Pin 1 index located at top-left corner with beveled edge marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT374PW, SN74HCT574PW offers identical functionality with reversed OE polarity-requiring signal inversion in control logic-while 74ACT374PW delivers faster switching at the cost of TTL incompatibility and significantly higher static power consumption.

Availability

SN74HCT374PW is available at Aetrix Electronics and suitable for industrial PLC I/O modules, legacy bus interface adapters, embedded display controllers, and automated test equipment requiring stable component supply and long-term obsolescence management.

Supply support for SN74HCT374PW 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 industrial-grade logic families.

The SN74HCT374PW belongs to TI's HCT (High-Speed CMOS TTL-compatible) logic series, designed specifically for robust 5-V system interfacing, bus buffering, and register storage in noise-prone industrial and instrumentation environments.

FAQ

What is the maximum clock frequency supported by the SN74HCT374PW?

The SN74HCT374PW supports a maximum clock frequency of 25 MHz under recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = –40°C to 85°C). This is derived from the minimum clock pulse width (tw = 20 ns min at 4.5 V) and confirmed by fmax = 25 MHz in the switching characteristics table for SN74HCT374 devices. Operation beyond this limit risks setup/hold violations and metastability.

Does the SN74HCT374PW require external pull-up or pull-down resistors on unused inputs?

Yes - all unused inputs of the SN74HCT374PW must be tied to either VCC or GND to prevent floating states that cause excessive ICC, logic contention, or erratic behavior. The datasheet explicitly mandates this in Section 5.2 Recommended Operating Conditions and Section 9 Layout Guidelines. Leaving inputs unconnected violates functional reliability requirements.

Can the SN74HCT374PW drive a 150-pF bus load reliably?

Yes - the SN74HCT374PW is fully characterized for CL = 150 pF, with tpd = 52 ns (max, 5.5 V) and ten/tdis = 45 ns (max, 5.5 V). Its ±6-mA output drive ensures clean signal edges into such loads, and the datasheet confirms operational validity across this capacitance in Sections 5.7 and 7.1.

Is the SN74HCT374PW pin-compatible with other TSSOP-20 octal latches like the SN74LS374?

No - while both are octal D-type latches in TSSOP-20 packages, the SN74HCT374PW has active-low OE (pin 11), whereas SN74LS374 uses active-high OE (pin 11). Additionally, SN74LS374 lacks 3-state outputs and exhibits different timing, drive strength, and input thresholds. Direct replacement is not electrically or functionally valid.

What is the thermal resistance (RθJA) of the SN74HCT374PW in its TSSOP package?

The junction-to-ambient thermal resistance (RθJA) for the SN74HCT374PW in TSSOP-20 (PW) package is 83°C/W, as specified in Section 5.3 Thermal Information of the datasheet. This value assumes standard JEDEC JESD51-2 PCB mounting conditions (single-layer copper, 1 in² copper area) and must be used in thermal design calculations for worst-case power dissipation scenarios.