Texas Instruments SN74AC244PW

Overview

SN74AC244PW from Texas Instruments is an octal non-inverting 3-state buffer/driver IC designed for bus-oriented data transmission, memory address driving, and clock distribution. It operates from 2 V to 6 V, supports 5-V and 3.3-V systems, delivers ≤7.5 ns propagation delay at 5 V, and features dual independent 4-bit channels with separate output-enable controls - used in server backplanes and telecom line cards.

For engineers reviewing the SN74AC244PW datasheet, SN74AC244PW pinout, SN74AC244PW application, or SN74AC244PW equivalent, key selection criteria include its TSSOP-20 package (6.5 mm × 4.4 mm), 3-state output architecture, rail-to-rail input voltage tolerance (up to 6 V), thermal resistance (R_θJA = 126.2 °C/W), and compatibility with legacy AC logic families.

Technical Context

The SN74AC244PW implements two independent 4-bit non-inverting buffers, each controlled by a dedicated output-enable (OE) input. Its CMOS AC technology enables high-speed operation with low power consumption and TTL-compatible input thresholds across the full 2–6 V supply range.

Each channel drives up to ±24 mA per output at 5 V, supports hot-swap-capable 3-state outputs, and maintains stable logic states during power sequencing when OE is pulled high via external resistor - critical for bus arbitration in multi-driver systems like network switch control planes.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, 1.2 mm max height, exposed pad optional for thermal enhancement (not electrically connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APW and SN74HC244N, the SN74AC244PW uniquely balances 5 V tolerance, 7.5 ns speed, and TSSOP-20 footprint - making it optimal for upgrading legacy 5 V designs without redesigning power or layout.

Availability

SN74AC244PW is available at Aetrix Electronics and suitable for server backplanes, LED display controllers, and telecom line cards requiring stable component supply across extended product lifecycles.

Supply support for SN74AC244PW 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 SN74AC244PW belongs to TI's AC logic family - engineered for high-speed, low-power, mixed-voltage digital interfacing in infrastructure and computing equipment where reliability and timing precision are critical.

FAQ

What is the maximum supply voltage for SN74AC244PW?

The absolute maximum V_CC rating for SN74AC244PW is 7 V, but the recommended operating range is 2 V to 6 V. Operating at 6 V ensures full specification compliance for parameters including t_PD, I_OH/I_OL, and VIH/VIL thresholds. Exceeding 6 V risks parametric degradation or long-term reliability impact, so SN74AC244PW should be limited to 6 V in production designs.

Does SN74AC244PW support hot-plug operation?

Yes, SN74AC244PW supports hot-plug operation due to its 3-state outputs and input overvoltage tolerance. When V_CC is off, inputs remain protected up to 6 V, and outputs default to high-impedance if OE is held high externally. However, SN74AC244PW requires external pullup resistors on both OE pins during insertion to prevent bus contention - TI recommends ≥10 kΩ to limit current during V_CC ramp-up.

Can SN74AC244PW drive 50-Ω transmission lines directly?

Yes, SN74AC244PW can drive 50-Ω transmission lines directly under defined conditions: at V_CC = 5 V, it delivers ±24 mA, supporting a 50-Ω load with ≤1 V drop (24 mA × 50 Ω = 1.2 V). For clean 3.3 V signaling, use V_CC = 3.3 V and verify waveform integrity with scope measurement - SN74AC244PW's 7.5 ns t_PD and fast edge rates make it suitable for short-run 50-Ω traces up to 15 cm.

What is the thermal pad connection requirement for SN74AC244PW?

SN74AC244PW does not have a thermal pad - that feature applies only to the RKS (VQFN) variant. The PW (TSSOP) package uses standard gull-wing leads with no exposed metal pad. Thermal performance relies on PCB copper area under the package body and proper V_CC/GND plane coupling. R_θJA is specified at 126.2 °C/W for the PW package with JEDEC-standard 2-layer board layout.

How do the two OE pins on SN74AC244PW function independently?

The two OE pins (Pin 1 = 1OE, Pin 19 = 2OE) control separate 4-bit channels: 1OE enables Y1–Y4 (driven by A1–A4), and 2OE enables Y1'–Y4' (driven by A1'–A4'). Each OE is active-low and operates independently - allowing one channel to drive while the other remains high-Z. This enables dynamic bus segmentation, e.g., routing different data streams to separate memory banks without external logic, a capability confirmed in the SN74AC244PW function table and timing diagrams.