DM74ALS257MX

Overview

The DM74ALS257MX is a 3-STATE Quad 1-of-2-Line Data Selector/Multiplexer manufactured by onsemi. It operates within a supply voltage range of 4.5V to 5.5V and supports a free air operating temperature from 0°C to +70°C. The device features four independent multiplexers, each selecting one of two data inputs based on an output select line. Propagation delays for data inputs range from 2ns to 12ns, while select input delays range from 3ns to 25ns depending on the transition direction. Outputs are capable of driving bus lines directly with high-level current of -2.6mA and low-level current of 24mA.

Feature Summary

• Provides true data outputs for direct interfacing with bus-organized systems
• Features 3-STATE buffer-type outputs that drive bus lines directly
• Utilizes advanced oxide-isolated, ion-implanted Schottky TTL process
• Functionally and pin-for-pin compatible with standard Schottky and low power Schottky TTL counterparts

Applications

• Implementing n-bit paralleled data selectors for data buses
• Multiplexing dual data buses
• Routing 4-bit words from two sources to four outputs
• Source programmable counters

Procurement Notes

Verify the specific ordering suffix 'X' indicates tape and reel packaging as documented in the datasheet. Confirm the component is sourced from authorized channels to ensure authenticity, noting that this part was originally manufactured by Fairchild Semiconductor before acquisition by onsemi. Check RoHS compliance status through official documentation.

Selection Notes

Select the DM74ALS257MX when true data output polarity is required; use the DM74ALS258 for inverted outputs. Ensure the application requires quad 1-of-2-line selection capabilities. Verify that the system logic levels match the specified VIH and VIL thresholds. Consider the SOIC-16 package constraints for PCB layout and thermal management.

Part Context

This component belongs to the 74ALS logic family, known for improved AC performance over standard Schottky and Low Power Schottky variants. It serves as a data selector/multiplexer within the broader category of encoders, decoders, and multiplexers. The device is designed to minimize propagation delay time while maintaining compatibility with existing TTL-based system architectures.

Replacement Considerations

The DM74ALS258 is the functional equivalent offering inverted data outputs instead of true data. Other devices in the 74ALS series may provide similar multiplexing functions but require verification of pinout and electrical characteristics for direct replacement.