Texas Instruments SN74LVC139AD

Overview

SN74LVC139AD from Texas Instruments is a dual 2-line to 4-line decoder/demultiplexer in SOIC-16 package, operating from 1.65 V to 3.6 V, with max propagation delay of 6.2 ns at 3.3 V and inputs tolerant to 5.5 V. It enables mixed-voltage translation in address decoding and data routing applications for microcontroller peripherals and FPGA I/O expansion.

For engineers reviewing the SN74LVC139AD datasheet, SN74LVC139AD pinout, SN74LVC139AD application, or SN74LVC139AD equivalent, key selection criteria include its dual-decoder architecture with active-low enable, 5.5-V-tolerant inputs, sub-7-ns timing at 3.3 V, latch-up immunity (>250 mA), and SOIC-16 footprint compatibility with industrial temperature range (–40°C to +85°C).

Technical Context

This device integrates two independent 2-to-4 decoders sharing no internal logic coupling-each has dedicated select inputs (A, B), active-low enable (G), and four active-high outputs (Y0–Y3). The fully buffered inputs present only one normalized CMOS load, simplifying fanout design in high-speed digital systems.

Its input voltage tolerance up to 5.5 V-while powered from 1.65–3.6 V-enables direct interfacing with legacy 5-V logic without level shifters. Output drive strength is specified at ±24 mA (IOL/IOH) at 3.0 V, supporting TTL-compatible loads and moderate bus capacitance.

Key Specifications

Pinout & Package

SN74LVC139AD uses a 16-pin SOIC (D) package with 1.27 mm pitch, 10.4 mm × 6.2 mm body, and 2.00 mm max height. Pin 1 is marked by a beveled corner or notch on the package top edge.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual 2-to-4 decoder applications.

Compared with SN74LV139A and 74AHC139, SN74LVC139AD uniquely balances 5.5-V input tolerance, sub-7-ns speed at 3.3 V, and ultra-low static current-making it optimal for mixed-voltage, power-constrained industrial control nodes where reliability and interface flexibility are prioritized over raw speed or pure 5-V operation.

Availability

SN74LVC139AD is available at Aetrix Electronics and suitable for industrial control panels, automotive body electronics, and medical diagnostic equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVC139AD 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 connectivity technologies, with decades of experience in high-reliability logic and interface solutions.

The SN74LVC139AD belongs to TI's LVC (Low-Voltage CMOS) logic family, designed specifically for robust, low-power, mixed-voltage digital interfacing in industrial, automotive, and communications infrastructure applications.

FAQ

What is the maximum clock frequency supported by SN74LVC139AD?

SN74LVC139AD does not operate on a clock-it is a combinational logic device. Its usable switching rate is determined by propagation delay (tpd ≤ 6.2 ns at 3.3 V) and input transition rate (∆t/∆v ≤ 10 ns/V). For repetitive address changes, maximum toggle rate is ~80 MHz assuming clean edges and minimal loading. SN74LVC139AD performance remains stable across its full –40°C to +85°C operating range.

Can SN74LVC139AD be used with a 5-V microcontroller driving its inputs?

Yes. SN74LVC139AD inputs are explicitly rated for voltages up to 5.5 V regardless of VCC (1.65–3.6 V), making it ideal for interfacing 5-V MCUs like ATmega328P or legacy PIC devices to 3.3-V subsystems. No external level shifters are required. SN74LVC139AD maintains full logic functionality and timing specs under this condition.

Does SN74LVC139AD support hot-swap or live-insertion?

No. SN74LVC139AD is not hot-swap rated. Its absolute maximum ratings do not cover powered insertion scenarios, and the lack of Ioff (power-off protection) means unpowered VCC can cause back-powering or latch-up if inputs are driven. Always power VCC before applying input signals. SN74LVC139AD requires controlled power sequencing in modular systems.

What is the function of the NC pins on SN74LVC139AD?

SN74LVC139AD has no NC (No Connect) pins in the SOIC-16 (D) package. All 16 pins are electrically assigned per the terminal assignment table: pins 1–16 correspond to 1G, 1A, 1B, 1Y0, 1Y1, 1Y2, 1Y3, GND, VCC, 2G, 2A, 2B, 2Y0, 2Y1, 2Y2, 2Y3. Any mention of NC applies only to alternate packages (e.g., GQN/ZQN BGA variants), not SN74LVC139AD.

How does SN74LVC139AD handle unused inputs?

All unused inputs on SN74LVC139AD must be tied to a valid logic level-either VCC or GND-to prevent floating states that increase ICC, cause oscillation, or induce EMI. TI recommends connecting unused G (enable) inputs to VCC to disable their associated decoder, and unused A/B inputs to GND. This practice ensures predictable behavior and meets SCBA004 guidelines. SN74LVC139AD reliability depends on proper input termination.