CD74HC238M

Overview

The CD74HC238M is a high-speed CMOS decoder/demultiplexer manufactured by Texas Instruments. It features three binary address inputs and eight active-low outputs, designed for memory address decoding or data routing applications. The device operates within a supply voltage range of 2V to 6V and supports a wide operating temperature range from -55°C to +125°C. Packaged in a 16-pin SOIC surface-mount format, it provides low power consumption while maintaining speeds comparable to Low-Power Schottky TTL logic.

Feature Summary

• Features three binary address inputs to select one of eight active-low outputs
• Includes two active-low enable inputs and one active-high enable input to facilitate cascading
• Offers low power consumption typical of CMOS technology with High-Speed performance

Applications

• Memory address decoding systems
• Data routing applications
• Cascaded decoder configurations

Procurement Notes

Verify the specific manufacturer source, as Thomson Consumer Electronics also produced this part number. Confirm RoHS compliance status, as some listings indicate non-compliance. Ensure the package matches the required 16-SOIC footprint and validate the operating temperature range requirements against your system specifications before procurement.

Selection Notes

Select this component when a high-speed CMOS decoder with active-low outputs is required. It serves as an alternative to the HC138 series, which provides active-high outputs. Consider the enable pin configuration for system design flexibility. Verify that the 2V to 6V supply voltage range aligns with the target application's power constraints.

Part Context

This component belongs to the 74HC logic family, known for silicon gate CMOS technology. It shares functional similarities with the CD74HC138 but differs in output polarity. The CD74 prefix indicates a commercial grade variant within the broader 74-series logic ecosystem, widely used in digital electronics for signal selection and decoding tasks.

Replacement Considerations

CD74HC138M (Active-High Outputs)

FAQ

What is the difference between CD74HC238M and CD74HC138M?

The primary difference is the output polarity. The CD74HC238M provides active-low outputs, whereas the CD74HC138M provides active-high outputs. Both share the same input structure and enable logic.

How many enable pins does the CD74HC238M have?

It has three enable pins: two active-low enables (E1, E2) and one active-high enable (E3), allowing for flexible cascading of multiple decoders.