DM74LS156M

Overview

The DM74LS156M is a dual 2-line to 4-line decoder/demultiplexer from the 74LS series, manufactured by onsemi. It features open-collector outputs and operates within a supply voltage range of 4.75V to 5.25V. The device includes individual strobes for section control and input clamping diodes. Propagation delays range from 18ns to 53ns depending on the signal path and load capacitance.

Feature Summary

• Dual sections with common binary-address inputs and individual strobes
• Open-collector output configuration
• Input clamping diodes for transmission-line effect minimization

Applications

• Dual 2-to-4-line decoding
• Dual 1-to-4-line demultiplexing
• Cascading for larger word decoding or demultiplexing

Procurement Notes

Verify the specific ordering suffix 'M' corresponds to the SOIC package variant. Confirm the component status as the source indicates potential end-of-life conditions for legacy Fairchild parts now managed by onsemi. Ensure compatibility with existing system designs requiring open-collector logic levels.

Selection Notes

Select this component when open-collector outputs are required for wired-AND configurations or level shifting. Compare propagation delay specifications against system timing requirements. Verify that the 74LS logic family voltage and current characteristics align with the target application's interface needs.

Part Context

This part belongs to the DM74LSxx series of TTL logic devices. It is functionally related to the DM74LS155, which utilizes totem-pole outputs instead of open-collector. Both share identical pinouts and address/strobe logic but differ in output stage architecture.

Replacement Considerations

DM74LS155M (Totem-pole output variant)

FAQ

What is the difference between DM74LS155 and DM74LS156?

The DM74LS155 features totem-pole outputs, while the DM74LS156 utilizes open-collector outputs.

How does the strobe input function?

Individual strobes permit activating or inhibiting each of the 4-bit sections independently.