Texas Instruments 74ACT11244NT

Overview

74ACT11244NT from Texas Instruments is an octal noninverting 3-state buffer/line driver designed for memory address and bus driving applications. It features TTL-compatible inputs, 5-V supply operation (4.5 V to 5.5 V), ±24 mA output drive, 1.5 ns minimum propagation delay, and operates across −40°C to 85°C. Used in legacy industrial control backplanes and ISA-bus compatible systems.

For engineers reviewing the 74ACT11244NT datasheet, 74ACT11244NT pinout, 74ACT11244NT application, or 74ACT11244NT equivalent, key selection criteria include 3-state bus contention control, flow-through pinout for PCB layout optimization, EPIC CMOS process latch-up immunity (500 mA at 125°C), and compatibility with TTL-level input signaling in mixed-logic systems.

Technical Context

This device implements two independent 4-bit noninverting buffers, each with dedicated 3-state enable (1OE, 2OE). Inputs accept standard TTL voltage thresholds (VIL ≤ 0.8 V, VIH ≥ 2 V) while outputs swing rail-to-rail under load, supporting bidirectional bus interfacing when paired with complementary devices like the 74ACT11240.

Its EPIC 1-μm CMOS process delivers low dynamic power (27 pF typical power-dissipation capacitance per enabled buffer) and high noise immunity via center-pin VCC/GND placement. The flow-through architecture routes inputs on one side and outputs on the opposite side, minimizing trace crossovers in dense PCB layouts.

Key Specifications

Pinout & Package

74ACT11244NT uses a 24-pin plastic DIP (300-mil) package with through-hole mounting. Pin 1 is top-left corner (notch-up orientation); VCC (pin 24) and GND (pins 10–13) are centrally located to suppress switching noise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74ACT11244NT, the 74ACT244N offers identical logic function but reduced noise immunity from fewer ground pins, while the SN74ABT244N delivers superior speed and drive at the cost of higher static current and less robust latch-up tolerance-making 74ACT11244NT optimal for thermally constrained, electrically noisy legacy upgrades.

Availability

74ACT11244NT is available at Aetrix Electronics and suitable for industrial control backplanes, ISA-bus compatible instrumentation, and memory address buffering requiring stable component supply across long-lifecycle programs.

Supply support for 74ACT11244NT 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The 74ACT11244NT belongs to TI's Advanced CMOS Logic (ACT) product line, engineered for high-speed, low-power 5-V TTL-compatible interfacing in mission-critical industrial and computing infrastructure.

FAQ

What is the maximum operating temperature range for the 74ACT11244NT?

74ACT11244NT is characterized for operation from −40°C to +85°C. This extended industrial temperature range is validated per TI's production test flow and ensures parametric compliance-including propagation delay, output drive, and 3-state leakage-across the full span without derating. The EPIC process contributes to thermal stability, and the device maintains 500-mA latch-up immunity even at 125°C ambient stress conditions.

Does the 74ACT11244NT support true TTL input levels?

Yes, the 74ACT11244NT accepts standard TTL input voltage thresholds: VIL ≤ 0.8 V (guaranteed low) and VIH ≥ 2.0 V (guaranteed high) across the full operating temperature and voltage range. This allows direct connection to legacy 74LS, 74ALS, and other bipolar logic families without level-shifting circuitry-critical for maintaining signal integrity in mixed-technology systems where 74ACT11244NT serves as a bridge device.

How does the flow-through pinout of the 74ACT11244NT improve PCB layout?

The 74ACT11244NT places all inputs on the left side (pins 1–4, 16–19) and all outputs on the right side (pins 1–4, 9–12), enabling straight-line routing with zero layer transitions in 2-layer boards. This flow-through architecture eliminates vias and crossovers in dense address/data bus layouts-reducing parasitic inductance, improving signal fidelity, and accelerating layout completion. It is especially valuable in space-constrained industrial backplanes where 74ACT11244NT is commonly deployed.

What is the purpose of the four contiguous GND pins (10–13) on the 74ACT11244NT?

The four adjacent GND pins (10–13) on the 74ACT11244NT provide a low-inductance, high-current return path for all eight outputs and internal logic switching currents. This configuration minimizes ground bounce and supply noise coupling-especially critical during simultaneous 3-state transitions. Paired with center-located VCC (pin 24), it forms a symmetric power distribution structure that enhances high-speed signal integrity in electrically noisy environments where 74ACT11244NT is routinely applied.

Can the 74ACT11244NT be used as a direct replacement for the 74ACT244N?

The 74ACT11244NT shares identical logic function, AC timing, and DC electrical specifications with the 74ACT244N, and both use 24-pin DIP packages with VCC at pin 24. However, the 74ACT11244NT features four contiguous GND pins (10–13) versus two spaced GND pins (7, 14) on the 74ACT244N. While functionally interchangeable in most circuits, the enhanced grounding of 74ACT11244NT delivers superior noise immunity-so substitution should consider system-level EMI requirements before deployment.