SN74HC138QDRQ1

Overview

The SN74HC138QDRQ1 is an automotive-grade 3-to-8 line decoder/demultiplexer from the Texas Instruments SN74HC138 family. It operates within a supply voltage range of 2 V to 6 V and features a SOIC-16 surface-mount package. The device provides three binary select inputs to decode into eight active-low outputs, supported by two active-low and one active-high enable inputs for system expansion. It is qualified to AEC-Q100 standards with a maximum propagation delay of 45 ns and supports an operating temperature range from -40°C to +125°C.

Feature Summary

• Automotive qualification compliant with AEC-Q100 standards for reliability in vehicle electronics
• Wide supply voltage operation ranging from 2 V to 6 V for flexible power integration
• Three enable inputs facilitate simplified cascading and system expansion without external logic

Applications

• Automotive memory address decoding systems
• Data routing and demultiplexing in vehicle networks
• Industrial control logic interfacing

Procurement Notes

Verify that the specific part number suffix matches the required package variant and tape-and-reel specifications. Confirm AEC-Q100 qualification status is explicitly documented for the target automotive application tier. Ensure compatibility with the intended operating temperature range and supply voltage constraints before finalizing procurement orders.

Selection Notes

Select this component when automotive reliability and wide voltage tolerance are required for decoding applications. The HC series offers standard CMOS performance suitable for general-purpose logic. Consider the SOIC-16 footprint for PCB layout constraints. Verify that the 45 ns propagation delay meets the timing requirements of the specific data bus or memory interface being designed.

Part Context

This device belongs to the SN74HC138 family of decoders, distinguished by its high-speed CMOS technology and automotive grade designation. Unlike commercial variants, the QDRQ1 suffix indicates compliance with automotive environmental and reliability standards. It serves as a foundational logic block for address decoding and signal distribution in complex electronic architectures.

FAQ

What is the logic function of the enable inputs?

The device includes two active-low enables (G1A, G1B) and one active-high enable (G2). All three must be in their active states simultaneously for the selected output to activate.

How does the device handle output states when disabled?

When any enable input is in its inactive state, all eight outputs remain in a high-impedance or inactive state, preventing unintended signal activation on the bus.