Texas Instruments SN74LVC139ADT

Overview

SN74LVC139ADT 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, fully buffered inputs, and 5.5-V-tolerant inputs-used for address decoding in low-voltage microcontroller peripheral interfaces.

For engineers reviewing the SN74LVC139ADT datasheet, SN74LVC139ADT pinout, SN74LVC139ADT application, or SN74LVC139ADT equivalent, key selection criteria include VCC range compatibility (1.65–3.6 V), input voltage tolerance (up to 5.5 V), dual independent enable-controlled decoding paths, and SOIC-16 thermal performance (θJA = 73°C/W).

Technical Context

This device integrates two independent 2-to-4 line decoders, each with active-low enable (G) that doubles as a data input in demultiplexing mode. Inputs are fully buffered and compatible with both 3.3-V and 5-V logic families, enabling level translation in mixed-supply systems.

Each decoder implements positive-logic decoding with active-high outputs (Y0–Y3) and supports high-speed operation: tpd ≤ 6.2 ns at VCC = 3.3 V, with output drive capability of ±24 mA at 3.0 V and ground bounce (VOLP) < 0.8 V under switching conditions.

Key Specifications

Pinout & Package

SN74LVC139ADT uses a 16-pin SOIC (D) package measuring 10.4 mm × 5.4 mm × 2.0 mm max height, with standard 1.27-mm lead pitch and gull-wing leads. Thermal resistance θJA is 73°C/W (JEDEC Std PCB).

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, SN74LVC139ADT uniquely balances 1.65–3.6-V operation, 5.5-V input tolerance, and 6.2-ns speed-making it the only option suitable for direct integration into modern 3.3-V embedded systems interfacing with legacy 5-V peripherals without redesign.

Availability

SN74LVC139ADT is available at Aetrix Electronics and suitable for industrial I/O expansion, microcontroller peripheral selection, FPGA configuration routing, and legacy system interface adaptation requiring stable component supply and long-term manufacturability.

Supply support for SN74LVC139ADT 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 over 50 years of innovation in logic and interface solutions.

The SN74LVC139ADT belongs to TI's LVC (Low-Voltage CMOS) logic family, designed specifically for high-speed, low-power, mixed-voltage system interfacing in portable, industrial, and automotive electronics.

FAQ

What is the recommended operating voltage range for SN74LVC139ADT?

The SN74LVC139ADT is specified for reliable operation from 1.65 V to 3.6 V. Operation below 1.65 V may result in undefined output states or increased propagation delay; above 3.6 V violates absolute maximum ratings and risks permanent damage. The device achieves optimal timing and drive strength at 3.3 V.

Can SN74LVC139ADT accept 5-V input signals safely?

Yes, SN74LVC139ADT inputs tolerate up to 5.5 V regardless of VCC level-this is explicitly guaranteed in the datasheet. This allows direct connection to 5-V logic outputs without external resistors or clamps, making it ideal for bridging legacy and modern voltage domains.

Does SN74LVC139ADT support demultiplexing functionality?

Yes-each decoder section uses its active-low enable (G) input as a data line: when G is asserted, the selected Yx output mirrors the state of G, effectively converting the 2-to-4 decoder into a 1-to-4 demultiplexer with address-controlled routing.

What is the thermal performance of SN74LVC139ADT in SOIC package?

SN74LVC139ADT in SOIC (D) package has a junction-to-ambient thermal resistance (θJA) of 73°C/W under JEDEC-standard PCB conditions. At 25°C ambient and 10 mA average output current per channel, junction temperature rise remains under 15°C-well within safe operating limits.

Are unused inputs required to be terminated on SN74LVC139ADT?

Yes-TI specifies that all unused inputs must be tied to VCC or GND to prevent floating nodes, which can cause excessive ICC, oscillation, or ESD susceptibility. This requirement is documented in TI application report SCBA004 and applies to all LVC-series devices including SN74LVC139ADT.