Texas Instruments SN74LVC138ADGVR

Overview

SN74LVC138ADGVR from Texas Instruments is a 3-line to 8-line decoder/demultiplexer in TVSOP-16 package, operating from 1.65 V to 3.6 V with 5.8 ns max propagation delay at 3.3 V, inputs tolerant to 5.5 V, and designed for memory decoding and data routing in LED matrix column selection and industrial control logic.

For engineers reviewing the SN74LVC138ADGVR datasheet, SN74LVC138ADGVR pinout, SN74LVC138ADGVR application, or SN74LVC138ADGVR equivalent, key selection criteria include enable-input logic configuration (G1 active-high, G2A/G2B active-low), output polarity (active-low Y0–Y7), supply voltage range compatibility, propagation delay vs. VCC dependency, and TVSOP-16 thermal performance (RθJA = 122.1°C/W).

Technical Context

The SN74LVC138ADGVR implements a binary-select decoder with three address inputs (A, B, C) and three enable inputs (G1, G2A, G2B) to activate exactly one of eight active-low outputs (Y0–Y7). All outputs remain high when any enable is inactive - enabling hierarchical decoding without external inverters.

Its CMOS design supports mixed-voltage interfacing: inputs accept up to 5.5 V independent of VCC (1.65–3.6 V), making it suitable for level translation between 3.3-V controllers and 5-V peripherals. Output drive capability is ±24 mA at 3.0 V, with ground bounce (VOLP) < 0.8 V and undershoot (VOHV) > 2 V at 3.3 V.

Key Specifications

Pinout & Package

SN74LVC138ADGVR uses the TVSOP-16 (DGV) package: 3.60 mm × 4.40 mm body, 0.5-mm lead pitch, 16-pin surface-mount, RoHS-compliant with NiPdAu lead finish and MSL Level-1 rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC138N and 74LVT138PW, SN74LVC138ADGVR uniquely balances wide voltage operation (1.65–3.6 V), 5.5-V input tolerance, and sub-6-ns delay - making it the only choice for mixed-supply embedded systems requiring both low-voltage efficiency and legacy interface compatibility.

Availability

SN74LVC138ADGVR is available at Aetrix Electronics and suitable for LED matrix displays, industrial I/O expansion, and factory automation logic controllers requiring stable component supply, long-term lifecycle support, and RoHS-compliant TVSOP packaging.

Supply support for SN74LVC138ADGVR 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 and embedded processing solutions, with over 90 years of innovation in precision logic, power management, and signal chain technologies.

SN74LVC138ADGVR belongs to TI's LVC (Low-Voltage CMOS) logic family, engineered for high-speed, low-power decoding in space-constrained industrial and consumer electronics where voltage scalability and interface robustness are critical.

FAQ

What is the maximum clock or address toggle rate supported by SN74LVC138ADGVR?

SN74LVC138ADGVR does not operate on a clock; it is asynchronous. Its maximum usable toggle rate depends on propagation delay and system timing margins. With 5.8 ns max tpd at 3.3 V, it supports reliable address decoding up to ~100 MHz in well-designed layouts - assuming setup/hold times are met and output loading remains ≤30 pF. For SN74LVC138ADGVR, ensure input transition rates stay ≤10 ns/V per datasheet spec.

Can SN74LVC138ADGVR safely interface with 5-V microcontrollers driving its inputs?

Yes. SN74LVC138ADGVR inputs are rated for up to 5.5 V regardless of VCC (1.65–3.6 V), allowing direct connection to 5-V GPIOs without level shifters. This is confirmed in Section 6.3 (Recommended Operating Conditions) and Section 8.3.2 of the datasheet. For SN74LVC138ADGVR, this feature enables mixed-voltage system integration while maintaining signal integrity and ESD robustness.

How does the enable-input logic (G1, G2A, G2B) affect output behavior in SN74LVC138ADGVR?

In SN74LVC138ADGVR, all three enables must be simultaneously active for any output to go LOW: G1 must be HIGH, and both G2A and G2B must be LOW. If any enable is violated, all eight outputs (Y0–Y7) go HIGH. This triple-enable architecture allows hierarchical decoding - e.g., G1 can serve as global chip select, while G2A/G2B encode board-level or subsystem-level addressing.

Is SN74LVC138ADGVR suitable for driving LEDs directly, and what current limits apply?

Yes. SN74LVC138ADGVR outputs can sink up to 24 mA per pin at VCC = 3.0 V (Section 6.3), making them suitable for direct LED column driving with appropriate series resistors. Total device output current must not exceed ±100 mA (Section 6.1), and simultaneous sinking on multiple outputs requires derating. For SN74LVC138ADGVR, verify thermal dissipation in TVSOP-16 under worst-case load using RθJA = 122.1°C/W.

What PCB layout practices are recommended for SN74LVC138ADGVR to minimize noise and ensure timing integrity?

Place a 0.1-µF ceramic bypass capacitor within 2 mm of the VCC pin (Pin 16) and connect it directly to the GND pin (Pin 8) with short, low-inductance traces. Avoid 90° trace corners; use 45° chamfers or arcs. Route enable and address inputs away from noisy power or clock nets. For SN74LVC138ADGVR, keep output traces to LEDs or loads short and avoid stubs to prevent ringing from its fast 5.8 ns edges.