Texas Instruments SN74LV138ARGYR

Overview

SN74LV138ARGYR from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in a 16-pin VQFN (RGY) package, operating from 2 V to 5.5 V supply, with 9.5 ns maximum propagation delay at 5 V, Ioff-enabled partial-power-down capability, and mixed-mode voltage interface support. It selects one of eight active-low outputs using three binary address inputs (A0–A2) and three enable inputs (G2, G0, G1), serving in memory decoding and output expansion circuits.

For engineers reviewing the SN74LV138ARGYR datasheet, SN74LV138ARGYR pinout, SN74LV138ARGYR application, or SN74LV138ARGYR equivalent, key selection criteria include its 2–5.5 V VCC range, guaranteed tpd ≤9.5 ns at 5 V, Ioff leakage <5 μA, 3.3 V-compatible input thresholds, and VQFN-16 thermal performance (RθJA = 39°C/W).

Technical Context

The SN74LV138ARGYR implements standard CMOS logic with balanced push-pull outputs and dedicated enable architecture: two active-low (G0, G1) and one active-high (G2) enables allow hierarchical expansion without external inverters. Its functional mode table defines eight decoded outputs (Y0–Y7) as active-low, with all outputs high when any enable condition fails.

It supports partial-power-down via Ioff circuitry that disables outputs and limits backflow current when VCC = 0 V, and features input clamp diodes for ESD protection (HBM ±2000 V, CDM ±1000 V). The device meets JESD17 latch-up immunity (>250 mA) and operates across –40°C to +85°C.

Key Specifications

Pinout & Package

SN74LV138ARGYR is housed in a 4.00 mm × 3.50 mm, 16-pin VQFN (RGY) package with exposed thermal pad. Pin 1 is marked by a dot; the thermal pad must be soldered to PCB ground plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar decoder/demultiplexer applications.

Compared with SN74HC138DR and 74LVC138PW,118, the SN74LV138ARGYR delivers superior thermal performance (39°C/W), guaranteed Ioff for safe power sequencing, and faster propagation at 5 V - making it optimal for space-constrained, multi-voltage industrial and embedded applications.

Availability

SN74LV138ARGYR is available at Aetrix Electronics and suitable for LED matrix control, memory address decoding, and industrial I/O expansion requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74LV138ARGYR 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, scalability, and broad technical support.

The SN74LV138ARGYR belongs to TI's LV logic family, engineered for low-voltage operation (2–5.5 V), high-speed decoding, and robust mixed-signal system integration in industrial, automotive, and communications infrastructure.

FAQ

What is the maximum operating temperature for SN74LV138ARGYR?

The SN74LV138ARGYR is rated for operation from –40°C to +85°C ambient temperature. This range is validated per JEDEC JESD78 and applies across the full 2 V to 5.5 V VCC range. Thermal design must ensure junction temperature remains below 150°C, especially under sustained 12 mA output loading - the RθJA of 39°C/W in the RGY package enables this with modest PCB copper area.

Does SN74LV138ARGYR support 1.8 V input signals?

Yes, SN74LV138ARGYR supports 1.8 V input signals when powered at VCC ≥ 2 V. Its input thresholds scale with VCC (VIH ≥ 0.7×VCC, VIL ≤ 0.3×VCC), so at VCC = 2.5 V, VIH(min) = 1.75 V - safely accepting 1.8 V logic highs. This mixed-mode capability eliminates external level shifters in heterogeneous voltage systems.

Can SN74LV138ARGYR drive LEDs directly?

Yes, SN74LV138ARGYR can drive LEDs directly in common-anode configurations. Each active-low output sources up to 12 mA at VCC = 5 V (VOH ≥ 3.8 V), sufficient for standard 2–20 mA indicator LEDs. For higher current or constant-current needs, pair with external NPN transistors or MOSFETs - the Ioff feature prevents leakage when powered down.

What is the purpose of the thermal pad on SN74LV138ARGYR?

The exposed thermal pad on SN74LV138ARGYR is electrically connected to GND and serves as the primary heat conduction path from the die to the PCB. Soldering it to a solid GND plane reduces RθJA from 39°C/W to ≤25°C/W in optimized layouts, critical for maintaining junction temperature within limits during continuous 8-output switching at 5 V.

How does the enable structure of SN74LV138ARGYR simplify decoder expansion?

SN74LV138ARGYR uses two active-low (G0, G1) and one active-high (G2) enables, allowing direct cascading without external inverters. For example, a 24-line decoder uses three SN74LV138ARGYR devices: G2 of each is driven by a unique MSB combination, while G0/G1 share common lower address bits - eliminating six inverters versus single-enable alternatives.