Texas Instruments SN74AC244DBR

Overview

SN74AC244DBR from Texas Instruments is an octal 3-state buffer/driver IC designed for bus-oriented signal conditioning in memory address, clock distribution, and data transmission systems. It operates across 2V–6V V_CC, supports 5V/3.3V logic interfaces, delivers ≤7.5ns propagation delay at 5V, and drives ±24mA outputs - enabling robust level translation and fanout expansion in industrial control and telecom infrastructure.

For engineers reviewing the SN74AC244DBR datasheet, SN74AC244DBR pinout, SN74AC244DBR application, or SN74AC244DBR equivalent, key selection criteria include its dual 4-bit independent enable architecture, rail-to-rail input tolerance (up to 6V), high-speed switching performance, and SSOP-20 package compatibility with space-constrained PCB layouts.

Technical Context

The SN74AC244DBR implements two independent 4-bit non-inverting buffers, each controlled by a dedicated output-enable (OE) input (Pin 1 and Pin 19). Its CMOS AC logic family ensures low power consumption (I_CC ≤ 40 µA at 5.5V), fast edge rates (Δt/Δv ≤ 8 ns/V), and noise-immune operation across –40°C to +85°C ambient temperature.

Each buffer pair features symmetrical drive strength: VOH ≥ 3.76V at IOH = –24mA (V_CC = 4.5V), VOL ≤ 0.44V at IOL = 24mA, and input clamp current rating of ±20mA - supporting reliable interfacing with TTL, LVTTL, and mixed-voltage systems without external level shifters.

Key Specifications

Pinout & Package

SN74AC244DBR uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65mm pitch, 7.2mm × 7.8mm body dimensions, and 2mm max height - optimized for automated SMT assembly and thermal reliability in dense layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APWR and SN74AHCT244N, the SN74AC244DBR uniquely balances wide supply flexibility (2–6V), 5V bus compatibility, and sub-8ns speed - making it optimal for mixed-voltage industrial systems where voltage translation overhead must be avoided.

Availability

SN74AC244DBR is available at Aetrix Electronics and suitable for server backplanes, LED display controllers, telecom line cards, and motor-drive control boards requiring stable component supply across extended product lifecycles.

Supply support for SN74AC244DBR 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 high-reliability interface ICs.

The SN74AC244DBR belongs to TI's AC logic family - engineered for high-speed, low-power bus interfacing in industrial, computing, and communications equipment where signal integrity and voltage flexibility are critical.

FAQ

What is the maximum operating voltage for SN74AC244DBR?

The SN74AC244DBR supports a supply voltage range of 2V to 6V, with absolute maximum ratings up to 7V on V_CC. Its inputs tolerate voltages up to V_CC + 0.5V (max 6.5V), and it can accept 0–6V input signals regardless of V_CC level - making SN74AC244DBR ideal for mixed-voltage board designs without external level shifters.

Does SN74AC244DBR support hot-swap operation?

SN74AC244DBR incorporates input clamp diodes rated for ±20mA and output clamp diodes with the same rating, enabling limited hot-swap capability when used with current-limiting series resistors. However, TI recommends tying OE pins to V_CC via pull-up resistors during power-up to ensure outputs remain in high-impedance state until supply stabilizes - a practice critical for safe insertion into live backplanes.

How many independent buffer groups does SN74AC244DBR contain?

SN74AC244DBR contains two independent 4-bit non-inverting buffer groups: Group 1 (inputs 1A1–1A4 → outputs 1Y1–1Y4, enabled by 1OE on Pin 1) and Group 2 (inputs 2A1–2A4 → outputs 2Y1–2Y4, enabled by 2OE on Pin 19). This architecture allows time-multiplexed bus sharing or isolated signal routing within a single 20-pin SSOP package.

What is the thermal resistance (RθJA) of SN74AC244DBR in its DB package?

The SN74AC244DBR in the SSOP-20 (DB) package has a junction-to-ambient thermal resistance (RθJA) of 70°C/W under standard JEDEC test conditions. This value assumes a 1-inch² copper pad on the PCB with two internal layers - confirming suitability for continuous operation at full output drive (±24mA) in industrial ambient temperatures up to +85°C without forced airflow.

Can SN74AC244DBR drive 50Ω transmission lines directly?

Yes - SN74AC244DBR delivers ±24mA output drive at 4.5V, which corresponds to ~188Ω effective output impedance (V_OH/I_OH). When paired with series termination (e.g., 33Ω resistor at source), it achieves impedance matching to 50Ω PCB traces. Verified switching characteristics (t_PLH/t_PHL ≤ 7.5ns at 5V) confirm clean edge fidelity for sub-100MHz digital signaling without overshoot or ringing.