SN74HCS238BQBR

Overview

The SN74HCS238BQBR is a 3-to-8 line decoder and demultiplexer from the HCS logic family, manufactured by Texas Instruments. It features Schmitt-trigger inputs for noise immunity and operates within a supply voltage range of 2 V to 6 V. The device utilizes a WQFN-16 package with dimensions of 3.50 mm × 2.50 mm. It supports an extended ambient temperature range from -40°C to +125°C. Propagation delay varies between 7 ns and 54 ns depending on voltage and temperature conditions.

Feature Summary

• Schmitt-trigger inputs provide high noise rejection and tolerance for slow input signals
• Balanced CMOS push-pull outputs ensure similar sourcing and sinking current 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 in solid state memory systems

Procurement Notes

Verify the specific BQB ordering suffix corresponds to the WQFN-16 package configuration. Confirm that the component meets automotive or industrial qualification requirements if applicable to the target system. Ensure proper ESD handling protocols are followed during assembly due to the sensitivity of CMOS inputs.

Selection Notes

Select this component when high noise immunity is required for address decoding or data routing. The wide operating voltage range allows compatibility with various power supply standards. Consider the thermal resistance characteristics of the WQFN package for heat dissipation in dense layouts.

Part Context

This part belongs to the SN74HCS238 series, which includes variants in TSSOP, SOIC, and SOT-23 packages. The BQB suffix specifically denotes the WQFN form factor. Other series members share identical electrical functionality but differ in physical footprint and thermal properties.

Replacement Considerations

SN74HCS238PW

FAQ

How do the Schmitt-trigger inputs affect signal integrity?

The Schmitt-trigger architecture provides hysteresis, making the device tolerant to slow input transitions and noisy signals without increasing static power consumption.

What is the function of the three strobe inputs?

The G1, G0, and G2 inputs act as output enable controls. When any strobe is active, all outputs are forced low; otherwise, only the selected address output goes high.