Texas Instruments SN74HCT244PWG4

Overview

SN74HCT244PWG4 from Texas Instruments is an octal non-inverting 3-state buffer/line driver IC, organized as two independent 4-bit sections with separate output-enable (OE) controls. It operates at 4.5–5.5 V, delivers ±6 mA output drive per channel, exhibits 13 ns typical propagation delay at 5 V/50 pF, and drives up to 15 LSTTL loads - used in bus interfacing, memory address buffering, and LED display drivers.

For engineers reviewing the SN74HCT244PWG4 datasheet, SN74HCT244PWG4 pinout, SN74HCT244PWG4 application, or SN74HCT244PWG4 equivalent, key selection criteria include its TTL-compatible inputs, 3-state bus-driving capability, 20-pin TSSOP package, and guaranteed operation from –40°C to +125°C.

Technical Context

The SN74HCT244PWG4 implements dual 4-bit non-inverting buffers with independent active-low output-enable inputs (1OE, 2OE). When OE is low, data passes transparently from A-inputs to Y-outputs; when high, outputs enter high-impedance state - enabling bidirectional bus control without contention. Its HCT logic family ensures TTL voltage-level compatibility while maintaining CMOS power efficiency.

It features balanced rise/fall times (7–18 ns), low input current (≤1 µA), and robust noise immunity with VIH = 2.0 V and VIL = 0.8 V at 5 V supply. The device supports hot-swap-capable bus isolation via controlled enable timing (ten/tdis ≤ 48 ns max at 5.5 V).

Key Specifications

Pinout & Package

Packaged in a 20-pin TSSOP (PW), the SN74HCT244PWG4 measures 6.5 mm × 6.4 mm with 0.65 mm lead pitch. The body size is 6.5 mm × 4.4 mm, optimized for high-density PCB layouts while maintaining thermal performance (RθJA = 131.8°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal 3-state buffer applications.

Compared with SN74HCT244PWR, SN74HCT244PWG4 shares identical functionality and layout but differs in marking and packaging documentation; versus 74ACT244PC, it trades speed for lower power and superior noise immunity - making it optimal for industrial bus isolation where robustness outweighs marginal timing gains.

Availability

SN74HCT244PWG4 is available at Aetrix Electronics and suitable for industrial control systems, telecom infrastructure equipment, and LED display subsystems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74HCT244PWG4 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 decades of industrial-grade reliability validation.

The SN74HCT244 product line delivers TTL-compatible, low-power 3-state buffering for memory, bus, and interface applications - designed specifically to replace legacy bipolar drivers while maintaining pin-for-pin compatibility and improving density.

FAQ

What is the operating temperature range for SN74HCT244PWG4?

The SN74HCT244PWG4 is rated for operation from –40°C to +125°C. This extended industrial temperature range is confirmed in TI's SCLS175I datasheet Revision I (February 2025) under Recommended Operating Conditions and applies specifically to the PW package variant. It enables deployment in harsh environments such as motor control cabinets, base station equipment, and automotive under-hood modules where ambient heat exceeds commercial-grade limits.

Does SN74HCT244PWG4 require external pull-up resistors on its OE pins?

SN74HCT244PWG4 does not require external pull-up resistors on OE pins for basic operation, but TI recommends tying OE to VCC through a pullup resistor during power-up/down to ensure outputs remain in high-impedance state until firmware initializes. The minimum resistor value depends on the driver's current-sinking capability - typically 10 kΩ suffices for most MCU-controlled applications. This prevents bus contention during reset sequences.

Can SN74HCT244PWG4 drive LEDs directly?

SN74HCT244PWG4 can drive LEDs directly only in low-current indicator configurations (e.g., <2 mA per segment), as its absolute maximum output current is ±35 mA per pin and ±70 mA total for VCC/GND. For standard 20 mA LED segments, external current-limiting resistors are mandatory - and for higher brightness or multiplexed displays, dedicated LED drivers or transistor buffers are recommended to avoid exceeding ICC or thermal limits.

Is SN74HCT244PWG4 pin-compatible with SN74LS244N?

Yes, SN74HCT244PWG4 is functionally and pin-compatible with SN74LS244N in terms of logic behavior and pin assignment, but differs in package (TSSOP vs PDIP) and electrical characteristics: HCT offers CMOS power efficiency (80 µA vs ~35 mA ICC), higher noise immunity, and rail-to-rail output swing. No PCB redesign is needed if adapting from LS244N to SN74HCT244PWG4 using a TSSOP-to-DIP adapter or layout revision.

What is the maximum capacitive load SN74HCT244PWG4 can drive reliably?

SN74HCT244PWG4 is characterized up to 150 pF load capacitance in its switching specifications (tpd, ten, tdis), with timing parameters guaranteed across that range. Driving loads beyond 150 pF may increase propagation delay nonlinearly and risk signal integrity issues like ringing or undershoot - especially at 13 ns tpd. For >150 pF, TI recommends adding series termination or reducing trace length; the SN74HCT244PWG4 itself does not specify derating beyond this limit.