DM74AS157MX

Overview

The DM74AS157MX is a quad 2-line to 1-line data selector/multiplexer from the Advanced Schottky (AS) logic family. It features four independent multiplexers, each selecting one of two data inputs based on common select lines and an enable input. The device operates with a supply voltage range of 4.5V to 5.5V and provides true outputs. Designed for surface mount applications, it utilizes a 16-lead Small Outline Integrated Circuit (SOIC) package with a width of 3.90mm. The component supports an operating temperature range of 0°C to 70°C.

Feature Summary

• Contains four independent 2-to-1 data selectors within a single integrated circuit
• Utilizes Advanced Schottky technology for high-speed switching performance
• Provides buffered inputs and outputs to drive multiple loads
• Includes a separate strobe/enable input for controlling data flow

Applications

• Data routing in digital communication systems
• Address decoding and selection circuits
• General-purpose data selection in microprocessor interfaces
• Signal path switching in test and measurement equipment

Procurement Notes

Verify the specific manufacturer source, as this part has been associated with Fairchild Semiconductor and later acquired entities like onsemi. Confirm the exact suffix 'MX' corresponds to the 16-SOIC surface mount package. Check for obsolescence status, as AS series components may be discontinued or replaced by newer generations. Ensure compatibility with existing board layouts regarding pinout and thermal requirements before procurement.

Selection Notes

Select this component when high-speed data selection is required using standard TTL-compatible logic levels. The Advanced Schottky series offers faster propagation delays compared to standard LS or S series devices. Consider the 16-SOIC package constraints for PCB space. Verify that the 4.5V to 5.5V supply range aligns with the system power design. Evaluate if the obsolete status impacts long-term supply chain stability.

Part Context

This multiplexer belongs to the 74ASxx logic family, known for improved speed over earlier 74Sxx variants while maintaining similar power consumption characteristics. The DM74LS157 serves as a lower-speed alternative within the same functional category. The MX suffix typically denotes the SOIC package variant manufactured by Fairchild Semiconductor. This component represents a legacy high-performance logic solution for parallel data routing.

Replacement Considerations

Public confirmed substitutes include the DM74AS157N (PDIP version) and DM74AS158M (inverted output variant). Direct pin-compatible replacements from other manufacturers should be verified against the official datasheet specifications. Due to the obsolescence of the AS series, newer logic families may require level shifting or redesign.