MC74AC139MELG

Overview

The MC74AC139MELG is a high-speed dual 1-of-4 decoder/demultiplexer manufactured by onsemi. It contains two independent decoders, each accepting two binary weighted address inputs (A0-A1) and providing four mutually exclusive active-LOW outputs (O0-O3). Each decoder features an active-LOW enable input that can function as a data input for demultiplexing applications or generate minterms of two variables. The device operates within a supply voltage range of 2.0 V to 6.0 V and supports output source/sink currents of 24 mA. It is housed in a 16-lead EIAJ package.

Feature Summary

• Dual independent 1-of-4 decoder functionality with active-LOW mutually exclusive outputs
• Enable inputs support demultiplexer operation and minterm generation
• High-speed CMOS technology with robust 24 mA output drive capability

Applications

• Address decoding in microprocessor systems
• Data distribution via demultiplexer configuration
• Logic function generation using minterms

Procurement Notes

Verify the specific MELG suffix corresponds to the EIAJ-16 plastic package format. Confirm RoHS compliance status as specifications apply to both standard and Pb-free devices. Ensure the ordering part number matches the required tape and reel quantity if applicable. Cross-reference the manufacturer's current product status to confirm availability.

Selection Notes

Select this component when dual independent decoding or demultiplexing is required within a single package. The AC series offers higher speed performance compared to standard 74LS logic. Consider the 24 mA output drive strength for direct interfacing with loads. Verify that the operating voltage range aligns with the system's power supply rails.

Part Context

This device belongs to the 74AC logic family, known for high-speed CMOS performance. It is functionally compatible with other 74AC139 variants but differs in packaging. The EIAJ-16 package provides a specific footprint distinct from SOIC or DIP options. It serves as a core logic element for address mapping and signal routing tasks.

Replacement Considerations

MC74AC139DT

FAQ

Can the enable input be used as a data input?

Yes, the active-LOW enable input can function as the data input for a 4-output demultiplexer application.

What is the output state when the enable is HIGH?

When the enable input is HIGH, all four outputs are forced to the HIGH state regardless of the address inputs.