Nexperia USA Inc. 74HCT138BQ-Q100,11

Overview

74HCT138BQ-Q100 from Nexperia is an automotive-grade 3-to-8 line inverting decoder/demultiplexer with TTL-compatible inputs, operating from 4.5 V to 5.5 V, featuring three enable inputs (E1, E2 active LOW; E3 active HIGH), eight mutually exclusive active LOW outputs (Y0–Y7), and qualified to AEC-Q100 Grade 1 (−40 °C to +125 °C) for engine control and body electronics applications.

For engineers reviewing the 74HCT138BQ-Q100 datasheet, 74HCT138BQ-Q100 pinout, 74HCT138BQ-Q100 application, or 74HCT138BQ-Q100 equivalent, key selection considerations include input logic compatibility (TTL), propagation delay (19–53 ns at VCC = 4.5 V), output drive capability (±4 mA), thermal-enhanced DHVQFN16 package with side-wettable flanks, and automotive qualification status.

Technical Context

The device implements a combinational 3-bit binary address decoder with fully decoded active LOW outputs, where only one output goes LOW per unique A0–A2 combination when enables satisfy E1 = LOW, E2 = LOW, E3 = HIGH. Its multiple enable architecture supports cascading-e.g., four units plus one inverter enable 1-of-32 decoding without external logic.

Input clamping diodes allow safe interfacing to voltages exceeding VCC when used with current-limiting resistors. The DHVQFN16 package provides enhanced thermal performance and AOI-compatible solder joints, critical for high-reliability automotive PCB assembly.

Key Specifications

Pinout & Package

DHVQFN16 (SOT763-1) package: 2.5 mm × 3.5 mm × 0.85 mm body, no leads, 16 terminals, side-wettable flanks for automated optical inspection of solder joints.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HC138BQ-Q100, the HCT variant offers tighter TTL input compatibility and lower static current, while SN74LS138DR lacks automotive qualification and thermal performance - making 74HCT138BQ-Q100 optimal for new automotive designs demanding reliability and interoperability.

Availability

74HCT138BQ-Q100 is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS sensor interfaces, and infotainment peripheral selection requiring stable component supply across automotive production lifecycles.

Supply support for 74HCT138BQ-Q100 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 global semiconductor expert focused on essential efficiency technologies, delivering high-performance logic, analog, and MOSFET solutions for automotive, industrial, and consumer markets.

This device belongs to Nexperia's automotive-qualified logic portfolio, designed specifically for reliable signal routing and address decoding in harsh-environment electronic control units where AEC-Q100 compliance and thermal robustness are mandatory.

FAQ

What is the difference between 74HCT138BQ-Q100 and 74HC138BQ-Q100?

The 74HCT138BQ-Q100 uses TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V at VCC = 4.5–5.5 V), enabling direct interfacing with legacy 5 V TTL outputs. In contrast, the 74HC138BQ-Q100 requires CMOS-level inputs (VIH ≥ 3.15 V), making it better suited for 3.3 V or mixed-voltage systems. Both share identical pinout, package, and AEC-Q100 qualification.

Can 74HCT138BQ-Q100 be used as a demultiplexer?

Yes - by using one enable input (e.g., E1) as the data input and the other two enables (E2, E3) as strobes, the device functions as an 8-output demultiplexer. When E2 and E3 are held at valid enable states, the logic level applied to E1 appears inverted on the selected Yx output, allowing single-line-to-8-line signal distribution with address-controlled routing.

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

No - the exposed pad (terminal 1) has no electrical function and does not require soldering. If soldered, it must remain electrically floating or be connected to GND; it is not a mandatory thermal path. The package's thermal performance is validated with or without pad connection, per Nexperia's SOT763-1 specification.

What is the maximum propagation delay at 125 °C ambient temperature?

At Tamb = +125 °C and VCC = 4.5 V, the maximum propagation delay (tpd) is 53 ns for An→Yn and En→Yn transitions, as specified in Table 7 of the datasheet. This value accounts for worst-case process, voltage, and temperature (PVT) conditions and is guaranteed for AEC-Q100 Grade 1 operation.