SN74HCS138PWR

Overview

The SN74HCS138PWR is a 3-to-8 line decoder/demultiplexer from the HCS logic family, manufactured by Texas Instruments. It 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. The device features Schmitt-trigger inputs for noise tolerance and balanced CMOS push-pull outputs capable of ±7.8 mA drive current at 6 V. Propagation delay ranges from 7 ns to 54 ns depending on voltage and temperature. It is housed in a 16-pin TSSOP package.

Feature Summary

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

Applications

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

Procurement Notes

Verify the specific ordering suffix 'PWR' corresponds to the TSSOP-16 package and reel packaging configuration. Confirm that the component meets RoHS compliance requirements for your assembly process. Ensure the design accounts for the specified thermal resistance values associated with the TSSOP package type during operation.

Selection Notes

Select this component when low power consumption and high noise immunity are critical. The wide operating voltage range allows compatibility with various system power rails. The extended temperature rating makes it suitable for industrial environments where standard commercial grade parts may fail.

Part Context

This part belongs to the SN74HCS series, which combines high-speed CMOS performance with Schmitt-trigger input characteristics. It serves as a digital logic solution for address decoding and data routing in systems requiring robust signal integrity across varying environmental conditions.

Replacement Considerations

SN74HCS138PW: Same function in TSSOP-16 tube packaging. SN74HCS138DYYR: Same function in SOT-23-THN-16 tape and reel packaging. SN74HCS138BQREP: Same function in WQFN-16 tape and reel packaging.

FAQ

How do unused inputs affect power consumption?

Unlike standard CMOS, holding Schmitt-trigger inputs at valid levels other than VCC or ground causes minimal additional current draw, though they should still be terminated to prevent undefined states.

What is the maximum recommended capacitive load?

The device can drive a load with total capacitance less than or equal to 50 pF while meeting all datasheet specifications.