MC74ACT138NG

Overview

The MC74ACT138NG is a high-speed 1-of-8 decoder/demultiplexer manufactured by onsemi. It operates within a supply voltage range of 4.5 V to 5.5 V and features three binary weighted address inputs (A0, A2) and eight mutually exclusive active-LOW outputs (O0-O7). The device includes multiple input enables for parallel expansion capabilities. It utilizes a 16-lead Plastic Dual In-Line Package (PDIP-16) with through-hole mounting. The component supports an operating ambient temperature range from -40°C to +85°C.

Feature Summary

• Features TTL compatible inputs for direct interface with standard logic systems
• Provides demultiplexing capability using enable inputs as data strobes
• Supports easy parallel expansion to larger decoding configurations

Applications

• High-speed bipolar memory chip select address decoding
• System address decoding in digital circuits
• Demultiplexing applications requiring active-low outputs

Procurement Notes

Verify the specific ordering suffix 'N' corresponds to the PDIP-16 package configuration when sourcing. Confirm RoHS compliance status directly with the manufacturer or authorized distributors, as specifications apply to both standard and Pb-free devices. Ensure the procurement channel provides valid documentation matching the MC74ACT138 part number to guarantee authenticity and correct revision levels.

Selection Notes

Select this component when TTL-compatible inputs are required alongside AC speed performance. The 1-of-8 decoding architecture suits applications needing precise address selection. Consider the PDIP-16 package constraints regarding board space and thermal dissipation compared to surface-mount alternatives. Verify that the 4.5 V to 5.5 V supply voltage aligns with the target system power rails.

Part Context

This device belongs to the MC74AC/ACT138 family of decoders and demultiplexers produced by onsemi. The ACT variant specifically bridges the gap between AC speed and TTL input compatibility. The family offers various packaging options including SOIC and TSSOP, but the NG suffix designates the specific PDIP-16 through-hole version intended for general-purpose circuit integration.

Replacement Considerations

MC74ACT138D

FAQ

What is the function of the enable inputs?

The device has three enable inputs: two active-LOW (E1, E2) and one active-HIGH (E3). All outputs remain HIGH unless E1 and E2 are LOW and E3 is HIGH.

Can this device be used for demultiplexing?

Yes, it can function as an 8-output demultiplexer by utilizing one of the active-LOW Enable inputs as the data input while using the other enables as strobes.