DM74LS138SJ

Overview

The DM74LS138SJ is a Schottky-clamped 3-to-8 line decoder/demultiplexer manufactured by Fairchild Semiconductor. It operates within a supply voltage range of 4.75 V to 5.25 V and features a propagation delay of 27 ns at 5 V. The device supports an output high current of -2.6 mA and draws a maximum operating supply current of 40 mA. Designed for surface mount applications, it utilizes a 16-pin SOP-II package and functions reliably across an operating temperature range from 0 °C to +70 °C.

Feature Summary

• Schottky clamping suppresses line ringing and simplifies system design
• Three enable inputs reduce the need for external gates or inverters during expansion
• Fully buffered inputs present only one normalized load to the driving circuit

Applications

• High-performance memory decoding systems
• Data routing applications
• Demultiplexing circuits where enable inputs serve as data lines

Procurement Notes

Verify the specific suffix 'SJ' against official datasheets to confirm the SOP-II surface-mount package configuration. Ensure compatibility with standard 5V logic levels and check for RoHS compliance status if required by project specifications. Confirm that the manufacturer designation aligns with current onsemi holdings following corporate restructuring.

Selection Notes

Select this component when low propagation delay and high noise immunity are critical for memory addressing or data distribution tasks. The inclusion of three enable inputs facilitates cascading multiple units without additional logic gates. Verify that the SOP-II package footprint matches the target PCB layout constraints before finalizing the design.

Part Context

This part belongs to the DM74LS series of bipolar logic integrated circuits. It is functionally equivalent to other industry-standard 74LS138 decoders but is packaged in a surface-mount format suitable for automated assembly processes. The device represents a legacy component often utilized in established industrial and consumer electronics designs requiring robust TTL-compatible performance.

Replacement Considerations

Direct substitutes include the DM74LS138N (DIP) for through-hole requirements or equivalents from other manufacturers such as SN74LS138. Verify pinout compatibility and electrical characteristics before swapping packages.