DM74AS257N

Overview

The DM74AS257N 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 an operating temperature range of 0°C to +70°C. The device utilizes an Advanced oxide-isolated, ion-implanted Schottky TTL process. It features 3-STATE outputs capable of interfacing directly with bus lines. Propagation delay times for data inputs range from 15ns to 16ns, while select input delays range from 21ns to 29.5ns depending on transition direction.

Feature Summary

• Advanced oxide-isolated, ion-implanted Schottky TTL process
• Functionally and pin-for-pin compatible with Schottky, low power Schottky, and advanced low power Schottky TTL counterparts
• 3-STATE buffer-type output drive bus lines directly

Applications

• Bus-organized systems
• Multiplexing dual data buses
• Expanding any data input point

Procurement Notes

Verify the specific manufacturer origin, as this component was originally produced by Fairchild Semiconductor before its acquisition by onsemi. Confirm that the PDIP-16 package matches the N16E designation. Ensure the ordering code does not include the 'X' suffix unless tape and reel packaging is required, as standard units are supplied in tubes.

Selection Notes

Select the DM74AS257N when true data presentation is required at the outputs, distinguishing it from the inverted-output DM74AS258. This component is suitable for designs needing direct bus interfacing via 3-STATE outputs. Consider the improved AC performance over standard Schottky counterparts. Verify compatibility with existing system logic families such as LS or ALS TTL.

Part Context

This component belongs to the DM74AS series of high-speed logic devices. It serves as a quad multiplexer providing four independent 1-of-2 data selection paths. The device is designed to minimize propagation delay time through its specific internal architecture. It allows implementation of up to 300 sources for data buses when paralleled.

Replacement Considerations

SN74AS257D (Texas Instruments) is listed as a parameter equivalent substitute.