MC74VHC138D

Signal Switches, Multiplexers, Decoders Overview

The MC74VHC138D is a 3-to-8 line decoder manufactured by onsemi, utilizing advanced high-speed silicon gate CMOS technology. It operates within a supply voltage range of 2.0 V to 5.5 V and supports an operating temperature range from -55°C to +125°C. The device features three binary select inputs (A0-A2) and three enable inputs (E1-E3), providing eight active-low outputs (Y0-Y7). It achieves typical propagation delays of 5.7 ns at 5 V with a 15 pF load. The component is housed in a 16-pin SOIC package (Case 751B) and contains 122 FETs.

Signal Switches, Multiplexers, Decoders Feature Summary

• High-speed operation comparable to Bipolar Schottky TTL while maintaining low CMOS power dissipation
• Three dedicated enable inputs facilitate cascade connections and memory address decoding
• Inputs tolerate voltages up to 7 V, enabling interface between 5 V and 3 V systems
• Provides high noise immunity and stable output through a three-stage internal circuit

Signal Switches, Multiplexers, Decoders Applications

• Memory system address decoding
• Cascaded logic expansion
• Industrial control systems
• Telecommunications equipment

Signal Switches, Multiplexers, Decoders Procurement Notes

Verify the specific ordering suffix 'D' corresponds to the SOIC-16 package (Case 751B) as defined in the manufacturer's ordering information. Confirm that the procurement channel provides the standard tube packaging associated with this suffix variant. Ensure compliance with RoHS requirements if lead-free material is specified for the project.

Signal Switches, Multiplexers, Decoders Selection Notes

Select this component when a 3-to-8 decoder is required with wide voltage flexibility down to 2 V. The extended industrial temperature range (-55°C to +125°C) makes it suitable for harsh environments. Verify that the 16-pin SOIC footprint aligns with the PCB layout constraints and that the 8 mA output drive capability meets the load requirements.

Signal Switches, Multiplexers, Decoders Part Context

This part belongs to the MC74VHC138 series of decoders and demultiplexers. It is functionally compatible with other standard logic families regarding pinout and operation. The 'D' suffix specifically denotes the SOIC-16 surface-mount package option within the broader product family offered by onsemi.

Signal Switches, Multiplexers, Decoders Replacement Considerations

MC74VHC138DT

Signal Switches, Multiplexers, Decoders FAQ

How do the enable inputs affect the decoder operation?

Decoding occurs only when E3 is Low and both E1 and E2 are High. If E3 is High or either E1 or E2 is High, all outputs are inhibited and go High.

What is the input voltage tolerance?

The inputs can tolerate voltages up to 7 V, which allows safe interfacing between 5 V systems and 3 V systems without level shifting.