CD74HC238PWT

Overview

The CD74HC238PWT is a high-speed CMOS logic decoder and demultiplexer manufactured by Texas Instruments. It features three binary select inputs (A0, A1, A2) that determine which of the eight outputs is activated. The device operates on a single power supply ranging from 2V to 6V. It includes two active-low enable inputs and one active-high enable input to facilitate cascading multiple units. The component is housed in a 16-pin TSSOP surface-mount package and supports an operating temperature range from -55°C to +125°C.

Feature Summary

• Provides decoding and demultiplexing functions via three binary select lines controlling eight distinct outputs.
• Features dual active-low and single active-high enable inputs for flexible system integration and cascading capabilities.
• Utilizes high-speed silicon gate CMOS technology to achieve performance comparable to low-power Schottky TTL while maintaining low power consumption.

Applications

• Memory address decoding in digital systems.
• Data routing applications requiring signal distribution.
• Cascaded decoding configurations for expanded I/O control.

Procurement Notes

Verify the specific suffix 'WT' against official Texas Instruments documentation to confirm tape-and-reel packaging specifications and moisture sensitivity level. Ensure compatibility with standard 16-pin TSSOP footprints during PCB layout. Confirm RoHS compliance status through current manufacturer datasheets prior to final procurement decisions.

Selection Notes

Select this component when high-speed CMOS decoding is required alongside low power dissipation. The inclusion of multiple enable inputs makes it suitable for complex systems requiring hierarchical control. Verify that the 2V to 6V supply voltage range aligns with the target circuit design requirements.

Part Context

This part belongs to the CD74HC238 series, which shares functional similarities with the HC138 and HCT238 families. While the HC138 offers non-inverting outputs, the HC238 provides inverting outputs. Both series utilize identical control logic structures but differ in output polarity characteristics for specific interface needs.

Replacement Considerations

CD74HC238PW

FAQ

What is the function of the enable inputs?

The device has two active-low enable inputs and one active-high enable input. All enables must be in their active states for the selected output to activate, allowing for easy cascading of multiple decoders.

How does the HC238 differ from the HC138?

The primary difference is the output polarity. The HC238 produces normally low outputs that go high when selected, whereas the HC138 produces normally high outputs that go low when selected.