DM74AS157N

Overview

The DM74AS157N is a Quad 1 of 2 Line Data Selector/Multiplexer manufactured by onsemi, utilizing an Advanced oxide-isolated, ion-implanted Schottky TTL process. It contains inverters and drivers to supply full on-chip data selection to four output gates. The device features a separate STROBE input and selects a 4-bit word from one of two sources to route to the outputs. It operates within a supply voltage range of 4.5V to 5.5V and supports a free air operating temperature range of 0°C to +70°C.

Feature Summary

• Functionally and pin-for-pin compatible with Schottky, low power Schottky, and advanced low power Schottky TTL counterparts.
• Improved AC performance over standard Schottky and low power Schottky variants.
• Switching specifications are guaranteed over the full temperature and VCC range.

Applications

• Multiplexing dual data buses
• Expanding any data input point
• Implementing general four functions of two variables where one variable is common

Procurement Notes

Verify component authenticity through authorized distribution channels. Confirm package integrity upon receipt, as the PDIP variant is susceptible to mechanical stress during handling. Ensure storage conditions adhere to specified limits to prevent moisture damage prior to soldering. Review RoHS compliance documentation for material composition verification before integration into final assemblies.

Selection Notes

Select this component when high-speed switching is required in industrial environments. The AS157 provides true data output, contrasting with the inverted output of the AS158. Verify that the system logic levels align with the specified VIH and VIL thresholds. Consider the PDIP package constraints if surface mount alternatives are not feasible for the specific application requirements.

Part Context

This part belongs to the 74AS (Advanced Schottky) logic family, known for superior speed compared to standard TTL. The DM74AS157N specifically implements quad multiplexing functionality. It is distinct from the DM74ALS157 due to higher drive capabilities and faster propagation delays inherent to the Schottky technology used in its construction.

Replacement Considerations

SN74AS157D from Texas Instruments is documented as a direct substitute.