Texas Instruments SN74HCT244DWRG4

Overview

SN74HCT244DWRG4 from Texas Instruments is an octal non-inverting 3-state buffer/line driver IC designed for bus-oriented memory address and clock signal buffering in 5V TTL-compatible systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive per channel, exhibits 13ns typical propagation delay at 5V/50pF, and supports high-impedance outputs for bidirectional bus control. It is widely deployed in server I/O expansion and telecom infrastructure backplanes.

For engineers reviewing the SN74HCT244DWRG4 datasheet, SN74HCT244DWRG4 pinout, SN74HCT244DWRG4 application, or SN74HCT244DWRG4 equivalent, key selection criteria include 3-state enable timing (19ns max t_dis), LSTTL load compatibility (up to 15 loads), low quiescent current (≤80µA ICC), and SOIC-20 package thermal performance (R_θJA = 109.1°C/W).

Technical Context

The SN74HCT244DWRG4 implements two independent 4-bit non-inverting buffer sections, each with dedicated active-low output-enable (OE) inputs (Pin 1 and Pin 19). Its CMOS HCT logic family ensures TTL-level input thresholds (V_IL ≤ 0.8V, V_VIH ≥ 2.0V at V_CC = 4.5–5.5V) while delivering rail-to-rail CMOS output swing and high-current drive capability.

Each output transitions between low-impedance logic states and high-impedance off-state under OE control, enabling time-multiplexed bus sharing without contention. The device features low input current (±1µA max) and power dissipation capacitance of 40pF per buffer, supporting stable operation in noise-sensitive digital interfaces.

Key Specifications

Pinout & Package

SN74HCT244DWRG4 is packaged in a 20-pin SOIC (DW) with 12.80mm × 10.3mm footprint and 1.27mm pitch. The package is RoHS-compliant, lead-finished with NiPdAu, and rated MSL Level-1 (unlimited floor life).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT244DWR and SN74LV244A, SN74HCT244DWRG4 provides guaranteed TTL input compatibility and industry-standard SOIC-20 footprint with full RoHS compliance, making it optimal for drop-in replacement in legacy 5V infrastructure designs where input threshold matching is critical.

Availability

SN74HCT244DWRG4 is available at Aetrix Electronics and suitable for server backplanes, LED display controllers, and network switch control buses requiring stable component supply across extended product lifecycles.

Supply support for SN74HCT244DWRG4 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, automotive, and communications markets.

The SN74HCT244DWRG4 belongs to TI's 74HCT logic family, engineered for robust 5V TTL interoperability and high-noise-immunity bus interfacing in mission-critical infrastructure equipment.

FAQ

What is the operating temperature range for SN74HCT244DWRG4?

The SN74HCT244DWRG4 is specified for operation from –40°C to +85°C ambient temperature. This range is validated per TI's production test conditions and aligns with industrial-grade requirements for telecom and server applications. The device's thermal resistance (R_θJA = 109.1°C/W) ensures safe junction temperatures under typical board-level power dissipation.

Does SN74HCT244DWRG4 support true bidirectional data flow?

No, SN74HCT244DWRG4 is a unidirectional non-inverting buffer: data flows only from A inputs to Y outputs. Bidirectional operation requires external control logic to coordinate OE signals and manage directionality-unlike transceivers such as SN74LVC245. Each of its two 4-bit sections has independent OE control but no internal direction register.

Can SN74HCT244DWRG4 drive standard 5V TTL loads directly?

Yes, SN74HCT244DWRG4 is explicitly rated to drive up to 15 LSTTL loads per output. Its ±6mA output current at 5V meets or exceeds the LSTTL input current requirements (I_IL = –0.4mA, I_IH = 20µA), ensuring valid logic levels and noise margin across full temperature and voltage ranges without external pull-ups or buffers.

What is the recommended bypass capacitor for SN74HCT244DWRG4?

Texas Instruments recommends a 0.1µF ceramic capacitor placed as close as possible to Pin 20 (V_CC) and Pin 10 (GND). This minimizes high-frequency supply noise and prevents output ringing during fast edge transitions. For boards with multiple V_CC pins on other devices, additional 0.01µF–0.022µF capacitors may be paralleled for broadband decoupling.

How does the 3-state enable timing affect bus arbitration in SN74HCT244DWRG4?

SN74HCT244DWRG4 guarantees t_dis ≤ 48ns and t_en ≤ 48ns (at V_CC = 5.5V), defining the maximum time between OE assertion and valid output drive or high-impedance release. This allows precise bus turnaround control in synchronous systems-e.g., enabling one SN74HCT244DWRG4 to release the bus before another asserts, preventing contention in multi-master configurations.