Nexperia USA Inc. 74LVC138ABQ,115

Overview

74LVC138ABQ,115 from Nexperia is a 3-to-8 line inverting decoder/demultiplexer with three active-Low enable inputs (E1, E2) and one active-High enable input (E3), operating across 1.2 V to 3.6 V supply, delivering mutually exclusive outputs (Y0–Y7), and supporting mixed-voltage interfacing (3.3 V/5 V) in memory chip select and address decoding applications.

For engineers reviewing the 74LVC138ABQ,115 datasheet, 74LVC138ABQ,115 pinout, 74LVC138ABQ,115 application, or 74LVC138ABQ,115 equivalent, key selection considerations include its wide V_CC range (1.2–3.6 V), Schmitt-trigger inputs for noise immunity, -40 °C to +125 °C operation, DHVQFN16 thermal-enhanced package, and demultiplexing capability using enable inputs as data/strobe lines.

Technical Context

The 74LVC138ABQ implements a standard 3-input binary decoder logic with inverted outputs and triple-enable control: E1 and E2 must be LOW while E3 must be HIGH for any output to go LOW; all outputs remain HIGH otherwise. Its function table defines eight unique decoded states plus three enable conditions enabling cascading to 1-of-32 decoding.

Schmitt-trigger inputs provide hysteresis (typ. 0.3 V at V_CC = 3.3 V), improving noise margin against slow-rising/falling signals. The device supports direct TTL-level interfacing and operates with input overvoltage tolerance up to 5.5 V - critical for mixed-supply system translation between 3.3 V logic and legacy 5 V peripherals.

Key Specifications

Pinout & Package

DHVQFN16 (SOT763-1) package: 2.5 × 3.5 × 0.85 mm body, no leads, exposed thermal pad (non-soldered by default), 16 terminals in quad configuration with terminal 1 index area marked.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC138ARGYR and 74AHC138PW,118, the 74LVC138ABQ,115 uniquely supports 1.2 V operation and offers superior thermal performance in the DHVQFN package, making it optimal for space-constrained, wide-input-voltage, and high-temperature embedded applications.

Availability

74LVC138ABQ,115 is available at Aetrix Electronics and suitable for memory address decoding, peripheral chip select logic, legacy system voltage translation, and expandable logic control requiring stable component supply across industrial, test & measurement, and embedded computing programs.

Supply support for 74LVC138ABQ,115 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

Nexperia is a leading Dutch semiconductor manufacturer specializing in high-performance logic, analog, and discrete components, with core expertise in energy-efficient, high-reliability solutions for automotive and industrial markets.

The 74LVC138A belongs to Nexperia's LVC (Low-Voltage CMOS) logic family, engineered for ultra-low-power, wide-supply-operation, and robust noise immunity in space- and power-constrained embedded systems.

FAQ

Can the 74LVC138ABQ,115 operate reliably at 1.2 V supply?

Yes - the device is fully specified down to 1.2 V V_CC, with functional operation confirmed across -40 °C to +125 °C. At 1.2 V, propagation delay increases to max 14 ns, and output drive reduces to ±100 μA, but all logic functions remain valid per Table 6 and Table 7 of the datasheet Rev. 10.

Is the thermal pad on the DHVQFN16 package required to be soldered?

No - the exposed thermal pad (terminal 1 index area) has no electrical function and requires no solder connection. Per Figure 6 and datasheet note (1), it may remain floating or be connected to GND if thermal performance demands it, but soldering is optional and not electrically mandatory.

How does the 74LVC138ABQ,115 support demultiplexing functionality?

By using E3 as the data input (HIGH/LOW) and E1/E2 as strobe controls, the device routes that data to one of eight outputs (Y0–Y7) based on A0–A2 address bits. When E1=E2=LOW and E3=HIGH, the selected Yx goes LOW; all others stay HIGH - enabling true 1-to-8 data distribution.

What is the maximum clock frequency supported for address transitions?

The device does not operate on a clock; it is combinatorial. However, input transition rates are specified: Δt/ΔV ≤10 ns/V for V_CC = 2.7–3.6 V. For a 3.3 V supply, this implies minimum input rise/fall times of ~33 ns - supporting reliable operation with address changes up to ~15 MHz in practice, assuming proper signal integrity.