SN74LS138DG4

Overview

The SN74LS138DG4 is a 3-to-8 line decoder and demultiplexer manufactured by Texas Instruments. It operates within the LS logic series, utilizing a 16-pin SOIC surface-mount package. The device functions with a supply voltage range of 4.75V to 5.25V. Key electrical parameters include a propagation delay of 41ns, a maximum clock frequency of 35MHz, and an operating temperature range from 0°C to +70°C. It features three address inputs and eight active-low outputs.

Feature Summary

• Provides decoding and demultiplexing functionality for digital logic circuits
• Features three enable inputs for flexible chip selection and system expansion
• Outputs are active-low, ensuring only one output is low at any given time during operation

Applications

• Address decoding in microprocessor-based systems
• Data distribution in digital communication interfaces
• Control signal generation for peripheral devices

Procurement Notes

Verify the 'G4' suffix indicates lead-free compliance per manufacturer specifications. Confirm the 'D' suffix corresponds to the SOIC-16 package variant. Ensure the component meets RoHS directives if required for your assembly process. Cross-reference the datasheet revision date to confirm parameter consistency.

Selection Notes

Select this component when a standard TTL-compatible 3-to-8 decoder is required in a surface-mount design. The LS series offers a balance of speed and power consumption suitable for general-purpose logic applications. Consider the 16-pin SOIC footprint for PCB layout constraints compared to through-hole alternatives.

Part Context

This part belongs to the Texas Instruments SN74LS138 family, which includes variants such as the SN74LS138N (PDIP) and SN74LS138D (SOIC). The G4 suffix typically denotes environmental compliance, specifically lead-free manufacturing, while maintaining identical electrical characteristics to the standard SN74LS138D.

Replacement Considerations

Compatible substitutes include the SN74LS138D from other manufacturers adhering to the same pinout and electrical specs. Verify that alternative sources support the SOIC-16 package and the specific temperature grade.