Texas Instruments SN74HCT244DWRE4

Overview

SN74HCT244DWRE4 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) inputs. It operates at 4.5–5.5 V, delivers ±6 mA output drive per channel at 5 V, exhibits 13 ns typical propagation delay (tpd) under 50 pF load, and supports bus-oriented memory address and clock buffering in industrial control and telecom infrastructure.

For engineers reviewing the SN74HCT244DWRE4 datasheet, SN74HCT244DWRE4 pinout, SN74HCT244DWRE4 application, or SN74HCT244DWRE4 equivalent, key selection criteria include its TTL-compatible inputs, high-current 3-state outputs capable of driving 15 LSTTL loads, low 80 µA max ICC quiescent current, and SOIC-20 package compatibility with standard 5 V logic systems.

Technical Context

The SN74HCT244DWRE4 implements dual 4-bit non-inverting buffers with independent active-low output-enable controls (1OE, 2OE). Each section passes data from A-inputs to Y-outputs when its OE is low; outputs enter high-impedance state when OE is high - enabling bidirectional bus isolation without external direction control logic.

Its HCT logic family ensures TTL-voltage-level compatibility (VIH = 2 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V), while CMOS input structure limits input current to ≤1 µA. Output drive strength (±6 mA at VOH/VOL = 3.7/0.4 V) and fast switching (tpd = 13 ns typ @ CL = 50 pF, VCC = 5.5 V) support reliable signal integrity across moderate-length PCB traces.

Key Specifications

Pinout & Package

SN74HCT244DWRE4 is packaged in a 20-pin SOIC (DW) with 12.80 mm × 10.3 mm body size and standard 1.27 mm pitch. Pin 1 is marked by a beveled corner or dot; pin numbering follows counter-clockwise order from top-left when viewed from top with marking side up.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT244DWR, SN74HCT244DWRE4 offers identical performance but reflects an earlier RoHS exemption status; versus SN74LV244A, it trades speed and voltage flexibility for guaranteed TTL compatibility and robust 5 V operation - making it the preferred choice for industrial 5 V bus isolation where legacy interoperability is mandatory.

Availability

SN74HCT244DWRE4 is available at Aetrix Electronics and suitable for server memory buffering, LED display column driving, and industrial network switch backplane applications requiring stable component supply and long-term industrial temperature support.

Supply support for SN74HCT244DWRE4 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 90 years of innovation in industrial, automotive, and communications markets.

SN74HCT244DWRE4 belongs to TI's HCT logic family, designed specifically for high-density, high-drive 3-state bus interfacing in memory address drivers, clock distribution networks, and industrial I/O expansion systems.

FAQ

What is the operating temperature range for SN74HCT244DWRE4?

The SN74HCT244DWRE4 is specified for operation from –40°C to +85°C. This industrial-grade temperature range ensures reliable performance in network switches, LED display enclosures, and factory automation controllers where ambient conditions exceed commercial limits. The SOIC-20 package's thermal resistance (RθJA = 109.1°C/W) supports this rating under typical PCB copper pour conditions.

Does SN74HCT244DWRE4 require external pull-up resistors on its OE pins?

Yes - SN74HCT244DWRE4 OE pins (1OE, 2OE) are active-low and must be pulled high during power-up to ensure outputs remain in high-impedance state until firmware initializes them. A 10 kΩ resistor to VCC is recommended; lower values improve noise immunity but increase static current. TI specifies this requirement to prevent bus contention during reset sequences.

Can SN74HCT244DWRE4 drive standard 74LS logic loads directly?

Yes - SN74HCT244DWRE4 is explicitly rated to drive up to 15 LSTTL loads per output. Its ±6 mA output drive at 5 V meets the 400 µA input current requirement of LS-TTL inputs, and its TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V) allow direct connection to 74LS outputs without level shifting.

What is the maximum capacitive load SN74HCT244DWRE4 can drive while maintaining timing specifications?

SN74HCT244DWRE4 maintains its 13 ns typical propagation delay (tpd) specification with a 50 pF load. At 150 pF, tpd increases to 18 ns (max) at 5.5 V. For designs exceeding 100 pF total trace + stub capacitance, layout optimization or reduced edge rate may be needed to preserve setup/hold timing margins in synchronous bus applications.

Is SN74HCT244DWRE4 pin-compatible with other members of the SN74HCT244 family?

Yes - all SN74HCT244 variants (e.g., SN74HCT244DBR, SN74HCT244DWR, SN74HCT244PWR) share identical pinout and functionality in their respective packages. SN74HCT244DWRE4 uses the SOIC-20 (DW) footprint, matching SN74HCT244DWR and SN74HCT244DWRG4 exactly, enabling drop-in replacement within the same package variant.