SN74HCS138DYYR

Overview

The SN74HCS138DYYR is a high-speed silicon gate CMOS decoder manufactured by Texas Instruments. It functions as a 3-to-8 line decoder/demultiplexer housed in a 16-pin SOT-23-THN package. The device operates within a supply voltage range of 2 V to 6 V and supports an extended ambient temperature range from -40°C to +125°C. Key electrical characteristics include Schmitt-trigger inputs for noise tolerance, balanced push-pull outputs capable of ±7.8 mA drive at 6 V, and low power consumption with typical supply current of 100 nA.

Feature Summary

• Schmitt-trigger inputs provide high noise immunity and support slow input signal transitions.
• Balanced CMOS push-pull outputs ensure similar sourcing and sinking current capabilities.
• Three strobe inputs (G1, G0, G2) facilitate cascading and demultiplexing operations.

Applications

• Memory device selection with shared data bus
• Reducing required number of outputs for chip select applications
• Routing data

Procurement Notes

Verify the specific DYY suffix indicates the SOT-23-THN package configuration. Confirm RoHS compliance status through official manufacturer documentation. Ensure the ordering information matches the exact part number SN74HCS138DYYR to avoid pinout or functional discrepancies. Check for any recent datasheet revisions that may impact thermal or electrical specifications.

Selection Notes

Select this component when a compact 3-to-8 decoding solution is required with Schmitt-trigger input noise rejection. The wide operating voltage range suits systems requiring flexibility between 2 V and 6 V supplies. Consider the SOT-23-THN package constraints regarding thermal dissipation and board space limitations compared to larger packages like SOIC or TSSOP.

Part Context

This device belongs to the SN74HCS series of HCMOS logic components. It shares functional similarities with other decoders but distinguishes itself through the inclusion of Schmitt triggers on all inputs. The DYY variant specifically utilizes the thin SOT-23 form factor, offering a smaller footprint than standard SOIC packages while maintaining comparable electrical performance.

Replacement Considerations

SN74HCS138PW: TSSOP-16 package equivalent. SN74HCS138D: SOIC-16 package equivalent. SN74HCS138BQB: WQFN-16 package equivalent. Verify package dimensions and thermal characteristics when substituting.