Nexperia USA Inc. 74HCT238BQ-Q100X

Overview

74HCT238BQ-Q100 from Nexperia is an automotive-grade 3-to-8 line decoder/demultiplexer with TTL-compatible inputs, active-HIGH mutually exclusive outputs (Y0–Y7), three enable inputs (E1, E2 active LOW; E3 active HIGH), and operation over -40 °C to +125 °C. It supports memory chip select decoding and parallel expansion to 1-of-32 via four ICs and one inverter.

For engineers reviewing the 74HCT238BQ-Q100 datasheet, 74HCT238BQ-Q100 pinout, 74HCT238BQ-Q100 application, or 74HCT238BQ-Q100 equivalent, key selection factors include automotive AEC-Q100 Grade 1 qualification, DHVQFN16 package with side-wettable flanks for AOI, propagation delay ≤53 ns at VCC = 5.0 V, output drive capability of ±4.0 mA, and input clamping diodes enabling overvoltage-tolerant interfacing.

Technical Context

The device implements combinational logic decoding of three binary address inputs (A0–A2) into eight non-overlapping active-HIGH outputs, conditioned by a triple-enable architecture: outputs activate only when E1 = LOW, E2 = LOW, and E3 = HIGH. This enables hierarchical decoding and demultiplexing modes.

Its TTL-level input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 5.0 V) ensure compatibility with legacy 5 V logic families, while CMOS output stages deliver rail-to-rail swing and ±4.0 mA drive strength under recommended operating conditions.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT138QPWRQ1, the 74HCT238BQ-Q100 offers superior manufacturability via side-wettable flanks and better thermal performance; versus 74LVC138BQ-Q100, it provides guaranteed TTL input compatibility essential for retrofit or mixed-voltage automotive subsystems.

Availability

74HCT238BQ-Q100 is available at Aetrix Electronics and suitable for automotive engine control units, body control modules, instrument clusters, and ADAS camera interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74HCT238BQ-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 delivering high-performance, reliable components for automotive, industrial, and consumer applications, with leadership in logic, analog, and discrete technologies.

The 74HCT series targets automotive and industrial systems requiring TTL-compatible 5 V logic with AEC-Q100 qualification, emphasizing robustness, predictable timing, and seamless integration with legacy controller families.

FAQ

What is the maximum clock frequency supported by the 74HCT238BQ-Q100?

The 74HCT238BQ-Q100 is a combinational logic device with no internal clock; its speed is defined by propagation delay. With tpd ≤ 53 ns (max) at VCC = 5.0 V and CL = 15 pF, it supports address/data switching rates up to approximately 10–15 MHz in practical decoding applications, limited by system-level setup/hold timing margins.

Can the 74HCT238BQ-Q100 be used as a demultiplexer, and how is that configured?

Yes - configure one active-LOW enable input (E1 or E2) as the data input, hold the other two enables at fixed valid states (e.g., E1 = DATA, E2 = LOW, E3 = HIGH), and apply address bits A0–A2. Each rising/falling edge on the data input appears on exactly one Yn output, determined by the address, enabling 1-to-8 signal distribution.

Does the thermal pad (pin 1) require solder connection in the 74HCT238BQ-Q100 DHVQFN package?

No - the exposed thermal pad (terminal 1) has no electrical function and may remain unsoldered. If soldered, it must be either left electrically floating or connected to GND; no thermal or mechanical requirement mandates soldering, though doing so improves thermal dissipation by ~15%.

How does the 74HCT238BQ-Q100 handle input voltages exceeding VCC, such as 12 V sensor signals?

Internal input clamp diodes allow safe interface to overvoltage signals when used with series current-limiting resistors. For a 12 V input, a 10 kΩ resistor limits clamp current to <1 mA (per JS-001 HBM spec), protecting the input stage while maintaining logic-level recognition at the internal gate.