SN74ALS138AN3

Overview

The SN74ALS138AN is a 3-line to 8-line decoder/demultiplexer from the Texas Instruments ALS logic family. It features three binary-select inputs (A, B, C) and three enable inputs (G1, G2A, G2B). The device provides eight active-low outputs (Y0-Y7). It operates within a supply voltage range of 4.5 V to 5.5 V. Propagation delays are specified with maximum values of 22 ns for low-to-high transitions and 18 ns for high-to-low transitions. The component is housed in a 16-pin PDIP package and supports operation across an ambient temperature range of 0°C to 70°C.

Feature Summary

• Incorporates Schottky-clamped circuitry for high-speed performance
• Features two active-low and one active-high enable inputs to simplify cascading
• Designed specifically for high-performance memory decoding applications

Applications

• High-speed memory decoders
• Data routing systems
• Demultiplexing applications

Procurement Notes

Verify that the ordering suffix 'AN' corresponds to the standard plastic DIP-16 package configuration. Confirm RoHS compliance status as indicated in the manufacturer's packaging addendum. Ensure the procurement channel sources catalog-grade parts rather than military or QML variants. Validate that the specific batch meets the commercial operating temperature requirements.

Selection Notes

Select this component when system design requires fast propagation delay characteristics typical of the ALS logic family. Verify that the application utilizes a 5V power supply within the specified tolerance limits. Consider the availability of multiple enable inputs if the design necessitates complex expansion without external inverters. Evaluate the through-hole mounting requirement against available PCB layout constraints.

Part Context

This part belongs to the SN74ALS138A series of 3-line to 8-line decoders and demultiplexers manufactured by Texas Instruments. It is categorized under the Advanced Low-Power Schottky (ALS) logic family. The device is functionally compatible with other industry-standard 3-to-8 line decoders but offers distinct switching speed and power consumption characteristics defined by the ALS technology.

Replacement Considerations

SN74ALS138ANSR

FAQ

How many enable inputs does the SN74ALS138AN have?

The device has three enable inputs: one active-high (G1) and two active-low (G2A and G2B).

What is the output state when the enable conditions are not met?

When the enable conditions are not satisfied, all eight outputs remain in the high state.