SN74AS257D

Overview

The SN74AS257D is a quad 2-to-1 data selector/multiplexer from the Texas Instruments AS logic series, housed in a 16-pin SOIC package. It operates on a single supply voltage ranging from 4.5 V to 5.5 V. The device features four independent channels, each selecting between two data inputs (A and B) based on an A/B select line, with outputs routed to four Y lines. It includes an output-enable (OE) input that controls three-state outputs; when OE is high, outputs enter a high-impedance state. Characterized for operation within a temperature range of 0°C to 70°C.

Feature Summary

• Provides bus interface capabilities by multiplexing signals from multiple sources directly onto system buses without loading data lines when disabled.
• Features three-state outputs controlled by an active-high output-enable input to prevent signal interference during inactive periods.
• Designed specifically for high-performance systems requiring efficient data routing across organized bus architectures.

Applications

• Multiplexing signals from multiple data sources to shared system buses
• Routing data in high-performance computer architectures
• Implementing data selection logic in digital circuit designs

Procurement Notes

Verify the specific ordering suffix matches the required package type and moisture sensitivity level. Confirm RoHS compliance status and lead finish specifications against current project requirements. Ensure the operating temperature range aligns with environmental constraints. Cross-reference the manufacturer part number with authorized distributors to validate authenticity and production status before finalizing procurement orders.

Selection Notes

Select this component for applications requiring fast switching speeds and low power dissipation compared to standard TTL logic. Consider the SN74ALS257A if lower power consumption is prioritized over speed. Evaluate the SN74AS258 if inverted data selection functionality is needed instead of non-inverted selection. Ensure the 16-pin SOIC footprint fits the available PCB layout space.

Part Context

This device belongs to the Texas Instruments SN74AS family, known for advanced Schottky technology offering high speed. It serves as a functional equivalent to other quad multiplexers but distinguishes itself through its specific propagation delay characteristics and drive capability. The D suffix denotes the plastic small-outline package variant suitable for surface-mount assembly techniques.

Replacement Considerations

SN74ALS257D