MC74ACT138DTR2

Overview

The MC74ACT138DTR2 is a high-speed 1-of-8 decoder/demultiplexer from the 74ACT logic series, manufactured by onsemi. It accepts three binary weighted address inputs (A0-A2) and provides eight mutually exclusive active-LOW outputs (O0-O7). The device operates within a supply voltage range of 4.5 V to 5.5 V. It features TTL-compatible inputs and outputs capable of sourcing or sinking 24 mA. Packaged in a TSSOP-16 surface-mount configuration, it supports an operating temperature range of -40°C to +85°C.

Feature Summary

• Features multiple input enables allowing parallel expansion to larger decoding configurations
• Outputs are active-LOW and mutually exclusive when enabled
• Provides demultiplexing capability using enable inputs as data strobes
• Includes TTL compatible inputs for direct interface with standard logic

Applications

• High-speed bipolar memory chip select address decoding
• Parallel expansion to 1-of-24 or 1-of-32 decoders
• Demultiplexing applications utilizing enable inputs as data inputs

Procurement Notes

Verify that the specific ordering suffix matches the required package type and tape/reel specifications. Confirm RoHS compliance status if lead-free packaging is mandatory for the assembly process. Ensure the component is sourced from authorized distributors to guarantee authenticity and traceability according to manufacturer standards.

Selection Notes

Select this component when TTL-compatible inputs are required alongside AC speed performance. It is suitable for designs needing active-LOW decoding with sufficient drive current. Consider the TSSOP-16 package constraints and verify thermal management requirements for the specified industrial temperature range during system integration.

Part Context

This part belongs to the MC74AC/ACT138 family of 1-of-8 decoders. The 'ACT' designation indicates compatibility with TTL input levels while maintaining AC logic speeds. It shares functional similarities with the MC74AC138 but differs in input threshold characteristics. The DTR2 suffix specifically denotes the TSSOP-16 package with tape and reel shipping.

Replacement Considerations

MC74ACT138DR2 (SOIC-16 Tape & Reel)

FAQ

How does the device handle expansion?

Multiple input enables allow parallel expansion to a 1-of-24 decoder using three devices or a 1-of-32 decoder using four devices and one inverter.

What is the function of the enable inputs?

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