Texas Instruments SN74ALS244CDWR

Overview

SN74ALS244CDWR from Texas Instruments is an octal non-inverting buffer/line driver with 3-state outputs, designed for memory address and bus driving in TTL-compatible systems. It operates from 4.5 V to 5.5 V, delivers ±12 mA output drive, supports 0°C to 70°C industrial temperature range, and uses a 20-pin SOIC (DW) package for high-density PCB layouts - commonly deployed in legacy industrial control backplanes and data acquisition I/O expansion modules.

For engineers reviewing the SN74ALS244CDWR datasheet, SN74ALS244CDWR pinout, SN74ALS244CDWR application, or SN74ALS244CDWR equivalent, key selection criteria include guaranteed 3-state disable leakage (±20 µA), propagation delay ≤10 ns (tPLH/tPHL), output-enable timing (tPZL ≤24 ns), and compatibility with standard 5-V TTL logic families in bus-hold and address buffering roles.

Technical Context

This device implements two independent 4-bit non-inverting buffer groups (1A→1Y and 2A→2Y), each controlled by its own active-low 3-state enable input (1OE, 2OE). The pnp input structure reduces DC loading on driving sources, improving fan-out capability in cascaded TTL systems.

All outputs exhibit symmetrical active-low enable control, defined VOL ≤0.4 V at IOL = 12 mA and VOH ≥2.4 V at IOH = –3 mA under recommended operating conditions - ensuring robust noise margins and reliable bus arbitration in shared-data-path applications.

Key Specifications

Pinout & Package

SN74ALS244CDWR is housed in a 20-pin SOIC (DW) package, 7.5 mm × 12.8 mm body size, 1.27 mm lead pitch, 2.65 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALS244CN and SN74AS244ADWR, SN74ALS244CDWR offers optimal balance of proven reliability, SOIC manufacturability, and moderate speed/power for cost-sensitive industrial bus interfaces - avoiding both DIP assembly constraints and AS-family power/thermal trade-offs.

Availability

SN74ALS244CDWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy data acquisition systems, and embedded I/O expansion modules requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74ALS244CDWR 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.

SN74ALS244CDWR belongs to TI's legacy ALS (Advanced Low-Power Schottky) logic family, engineered for high-speed, low-power TTL-compatible interfacing in memory and bus systems of 1980s–2000s industrial electronics.

FAQ

What is the maximum operating supply voltage for SN74ALS244CDWR?

The absolute maximum supply voltage for SN74ALS244CDWR is 7 V, but the recommended operating range is strictly 4.5 V to 5.5 V. Operation outside this range may cause parametric shift or permanent damage. All published specifications - including VOH, VOL, and propagation delay - are guaranteed only within the 4.5–5.5 V window. Exceeding 5.5 V risks violating internal junction limits, even briefly during power-up transients.

Does SN74ALS244CDWR support hot-swap or live-insertion into a powered bus?

SN74ALS244CDWR is not rated for hot-swap operation. Its absolute maximum rating for voltage applied to a disabled 3-state output is 5.5 V - exceeding bus voltage during insertion can cause latch-up or output-stage damage. For live-insertion applications, external series resistors or dedicated hot-swap controllers must be used. The device's ±20 µA 3-state leakage is insufficient alone to guarantee safe bus arbitration during partial powering.

Can SN74ALS244CDWR drive CMOS loads directly?

Yes, SN74ALS244CDWR can drive CMOS inputs directly, provided the CMOS device accepts TTL-compatible logic thresholds (VIH ≥2.0 V, VIL ≤0.8 V) and operates from the same 5-V supply. Its VOH ≥2.4 V at –3 mA and VOL ≤0.4 V at 12 mA exceed standard 74HC/74HCT input requirements. However, capacitive loading beyond 50 pF may degrade tPLH/tPHL performance, so trace length and fan-out should be verified per application.

What is the function of pins 1OE and 2OE on SN74ALS244CDWR?

Pins 1OE and 2OE are active-low output-enable controls for two independent 4-bit buffer sections: 1OE governs outputs 1Y1–1Y4 (driven by inputs 1A1–1A4), and 2OE governs outputs 2Y1–2Y4 (driven by 2A1–2A4). When either OE pin is low, its associated outputs pass inputs non-inverted; when high, those outputs enter high-impedance state. This enables selective bus partitioning without external logic.

Is SN74ALS244CDWR pin-compatible with SN74LS244N?

Yes, SN74ALS244CDWR is functionally and pin-compatible with SN74LS244N in terms of logic behavior, pin assignment, and electrical interface - both feature identical 20-pin dual-in-line functional mapping (including VCC, GND, OE, A, Y positions). However, SN74ALS244CDWR uses SOIC packaging while SN74LS244N uses PDIP; physical layout differs, but schematic symbol and netlist connectivity remain interchangeable for redesign purposes.