DM7442N

Overview

The DM7442N is a TTL/H/L series decimal decoder/driver manufactured by National Semiconductor. It functions as a 4-line BCD to decimal converter, providing ten active-low outputs corresponding to the binary-coded decimal input states. The device utilizes an open-collector output configuration and is housed in a standard 16-pin PDIP package. Designed for digital signal decoding applications, it accepts TTL-compatible inputs and delivers inverted outputs suitable for driving external loads or interfacing with subsequent logic stages within compatible circuit architectures.

Feature Summary

• Performs conversion of four-bit binary-coded decimal inputs into one of ten mutually exclusive active-low decimal outputs
• Features open-collector output structure allowing flexible interfacing and wired-logic capabilities
• Compatible with TTL/H/L logic families ensuring broad integration within standard digital systems

Applications

• BCD to decimal decoding in digital display drivers
• Address decoding in memory or I/O mapping circuits
• Control signal generation in sequential logic systems

Procurement Notes

Verify component authenticity due to obsolete status and potential surplus availability. Confirm package integrity and pin alignment for the 16-pin DIP form factor. Check datasheet revisions for any specific handling or electrical characteristic updates from National Semiconductor. Ensure compatibility with existing TTL voltage levels and load requirements before integration.

Selection Notes

Select this component when a dedicated BCD-to-decimal translation function is required within a TTL-based design. Consider the open-collector outputs for level shifting or current sourcing needs. Evaluate space constraints against the 16-pin DIP footprint. Verify that the inactive state behavior aligns with system safety requirements, as only one output is active per valid input code.

Part Context

Part of the National Semiconductor 74-series logic family, specifically the DM7442 variant. This component belongs to the broader category of combinational logic decoders used extensively in mid-20th-century digital electronics. Its design reflects standard TTL architecture principles, emphasizing reliable switching characteristics and standardized pinouts for backward compatibility with earlier 7400-series designs.

Replacement Considerations

Equivalent parts include other manufacturers' 7442 TTL decoders such as SN7442N. Verify pinout compatibility and electrical specifications before substitution. Note that some modern equivalents may offer different output structures or speed characteristics requiring circuit adjustment.