DM74AS257N

Overview

The DM74AS257N is a 3-STATE Quad 1-of-2 Data Selector/Multiplexer manufactured by Fairchild Semiconductor. It belongs to the AS logic series and features four independent multiplexers, each with two inputs and one output. The device utilizes a 16-pin DIP package with a 0.300-inch body width. It operates within a supply voltage range of 4.5V to 5.5V and supports through-hole mounting. The component functions as a data selector or multiplexer with tri-state outputs.

Feature Summary

• Provides four independent 1-of-2 data selection paths
• Features 3-STATE output capability for bus driving
• Compatible with standard TTL logic families

Applications

• Data routing in microprocessor systems
• Signal selection in communication interfaces
• Memory address decoding circuits

Procurement Notes

Verify the manufacturer designation carefully, as the DM prefix indicates Fairchild Semiconductor production. Confirm RoHS compliance status, as source documentation indicates this specific part number may not be compliant. Check current manufacturing status, as older AS series components from this era are frequently discontinued or obsolete. Ensure the 16-pin DIP package matches the target PCB footprint requirements before procurement.

Selection Notes

Select this component when a quad multiplexer with tri-state outputs is required for AS-series logic applications. It serves as a functional equivalent to other 74AS257 variants but requires verification of pinout compatibility with legacy designs. Consider power dissipation characteristics typical of Advanced Schottky technology compared to LS counterparts. Validate that the operating temperature range meets the environmental constraints of the final assembly.

Part Context

This component is part of the 74AS (Advanced Schottky) logic family, known for high-speed switching performance. The DM74AS257 specifically addresses the need for multiple data selectors in parallel configurations. It represents a transition period in semiconductor manufacturing where Fairchild produced parts under the National Semiconductor lineage specifications.