Texas Instruments SN74LVC138ADRE4

Overview

SN74LVC138ADRE4 from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in SOIC-16 package, operating from 1.65 V to 3.6 V with 5.8 ns max propagation delay at 3.3 V. It features three binary select inputs (A, B, C), two active-low enables (G2A, G2B), one active-high enable (G1), and eight active-low outputs (Y0–Y7). It is used in LED matrix column selection and memory address decoding where low-latency, level-shifted enable control is required.

For engineers reviewing the SN74LVC138ADRE4 datasheet, SN74LVC138ADRE4 pinout, SN74LVC138ADRE4 application, or SN74LVC138ADRE4 equivalent, this page delivers verified electrical specs, functional mode behavior, real-world use cases in industrial displays and automation systems, and validated alternative parts for supply continuity and design flexibility.

Technical Context

The SN74LVC138ADRE4 implements a combinational logic decoder with three-stage enable gating: G1 (active-high) and G2A/G2B (both active-low) must all be asserted to activate output decoding. Inputs tolerate up to 5.5 V, enabling interoperability between 1.8 V/2.5 V/3.3 V logic domains and legacy 5 V controllers without external level shifters.

Each output drives actively low with ±24 mA sink/source capability at 3.0 V, supporting direct LED column sinking in multiplexed displays. Propagation delay varies with supply voltage - 22 ns at 1.8 V, 6.7 ns at 3.3 V - and output skew is limited to 1 ns, ensuring tight timing alignment across Y0–Y7 in high-speed demux applications.

Key Specifications

Pinout & Package

SN74LVC138ADRE4 uses the SOIC-16 (D) package: 10.0 mm × 3.91 mm body, 1.27 mm pitch, gull-wing leads. Pin 1 is bottom-left corner (marking dot adjacent), with standard dual-in-line orientation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-to-8 decoder applications.

Compared with SN74HC138N and 74LVC138PW,118, the SN74LVC138ADRE4 uniquely combines 1.65 V operation, 5.5 V-tolerant inputs, and sub-6 ns delay - making it optimal for space-constrained, multi-voltage embedded systems requiring precise timing and interface flexibility.

Availability

SN74LVC138ADRE4 is available at Aetrix Electronics and suitable for LED matrix displays, industrial memory decoding, and factory automation I/O expansion requiring stable component supply and long-term production support.

Supply support for SN74LVC138ADRE4 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 decades of expertise in high-reliability industrial and automotive ICs.

The SN74LVC138A product line delivers advanced low-voltage CMOS decoders optimized for timing-critical memory and data-routing applications in industrial, computing, and infrastructure systems.

FAQ

What is the maximum propagation delay of the SN74LVC138ADRE4 at 3.3 V?

The maximum propagation delay of the SN74LVC138ADRE4 is 5.8 ns when measured from any select (A, B, C) or enable (G1, G2A, G2B) input to any output (Y0–Y7) at VCC = 3.3 V ± 0.3 V and TA = 25°C. This value is specified in the official Texas Instruments switching characteristics table and reflects worst-case performance under recommended operating conditions. The SN74LVC138ADRE4 achieves this low latency through optimized LVC-series CMOS design.

Can the SN74LVC138ADRE4 accept 5 V input signals while operating at 1.8 V VCC?

Yes, the SN74LVC138ADRE4 accepts input voltages up to 5.5 V regardless of VCC level - including when VCC = 1.8 V. This 5.5 V tolerance is explicitly guaranteed in the Electrical Characteristics table and enables safe interfacing with 5 V microcontrollers, sensors, or legacy peripherals without external level shifters. The SN74LVC138ADRE4 uses over-voltage tolerant input structures that protect internal circuitry while maintaining correct logic interpretation.

How does the enable logic work on the SN74LVC138ADRE4?

The SN74LVC138ADRE4 requires all three enables to be simultaneously active: G1 must be HIGH, and both G2A and G2B must be LOW. If any enable is violated - e.g., G1 = LOW or G2A = HIGH - all eight outputs (Y0–Y7) go HIGH (inactive state). This three-input enable scheme allows hierarchical decoding: multiple SN74LVC138ADRE4 devices can be cascaded using one device's outputs to control G1/G2A/G2B of downstream units without external inverters.

What package type and footprint does the SN74LVC138ADRE4 use?

The SN74LVC138ADRE4 uses the SOIC-16 (D) package: 10.0 mm × 3.91 mm body size, 1.27 mm lead pitch, gull-wing surface-mount leads. Its pinout matches industry-standard 16-pin SOIC footprints, and the device is RoHS-compliant with NiPdAu (NIPDAU) lead finish and Moisture Sensitivity Level 1 (unlimited floor life at ≤30°C/60% RH). The SN74LVC138ADRE4 is supplied in large tape-and-reel format (2500 units per reel) for automated assembly.

Is the SN74LVC138ADRE4 suitable for driving LEDs directly?

Yes, the SN74LVC138ADRE4 is designed to drive LEDs directly in multiplexed displays: each output (Y0–Y7) sinks up to 24 mA at VCC = 3.0 V, sufficient for standard 5 mm or SMD LEDs at typical duty cycles. Its active-low outputs align with common cathode column architecture, and its fast 5.8 ns turn-off minimizes ghosting. For continuous DC operation, derating per thermal limits applies - the SN74LVC138ADRE4's RθJA = 86.8°C/W requires careful PCB copper area management.