DM74S257N

Overview

The DM74S257N is a Schottky-clamped high-performance multiplexer featuring 3-STATE outputs for direct bus interface. It contains four independent 1-of-2 data selectors in a 16-lead Plastic Dual-In-Line Package (PDIP). The device operates within a supply voltage range of 4.75V to 5.25V and supports an operating temperature range of 0°C to +70°C. Typical power dissipation is 320 mW, with average propagation delay from data input at 4.8 ns.

Feature Summary

• Features 3-STATE outputs that allow direct interfacing with data lines of bus-organized systems.
• Schottky-clamped design provides significant improvement in AC performance.
• Enables implementation of n-bit paralleled data selectors with up to 258 sources for data buses.

Applications

• Bus interface from multiple sources in high-performance systems
• Data retention using standard TTL registers throughout the system

Procurement Notes

Verify manufacturer origin as this component was originally produced by Fairchild Semiconductor. Confirm package designation N16E matches requirements. Check RoHS compliance status as original datasheets may predate modern environmental directives. Ensure availability through authorized distributors or verified surplus channels given potential discontinuation.

Selection Notes

Select this component when bus organization requires multiple sources driving common lines without contention. The output disable times are shorter than enable times to prevent logic conflicts. Suitable for applications needing fast switching speeds provided by Schottky technology. Verify thermal management capabilities for typical power dissipation levels in enclosed environments.

Part Context

This part belongs to the 74S series of logic integrated circuits, characterized by Schottky clamping for speed. It functions as a quad 1-of-2 data selector/multiplexer. The 'N' suffix indicates a 16-lead plastic dual-in-line package. It is part of a family including similar 3-state versions like S157 and S158 with identical pin-outs.

Replacement Considerations

Direct substitutes include SN74LS257BN from Texas Instruments. Other compatible options may exist within the 74S or 74LS families, but verify electrical characteristics and pin compatibility before substitution.