SN74AS27D

Overview

The SN74AS257D is a quad 2-input 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 three-state outputs that interface directly with system buses without loading data lines when disabled. Electrical characteristics include a high-level output current of -15 mA and a low-level output current of 48 mA at 4.5 V. Propagation delays are specified between 1 ns and 11 ns depending on input-to-output paths.

Feature Summary

• Provides bus interface capabilities from multiple sources in high-performance systems
• Features three-state outputs that do not load data lines when the output-enable input is at a high logic level
• Designed to multiplex signals from 4-bit data sources to 4-output data lines in bus-organized architectures

Applications

• Multiplexing signals from 4-bit data sources to 4-output data lines
• Bus interface applications in high-performance systems
• Connecting multiple signal sources to shared data lines

Procurement Notes

Verify the specific ordering suffix against the manufacturer's official Package Option Addendum to confirm the exact physical package type, lead finish, and moisture sensitivity rating. Ensure the component status matches project requirements, as availability may vary by region or production cycle. Confirm RoHS compliance and operating temperature range specifications align with the target application environment before finalizing procurement.

Selection Notes

Select this component for designs requiring fast switching speeds within the AS logic family. Verify that the required operating temperature range of 0°C to 70°C meets environmental constraints. Ensure the power supply voltage remains strictly within the 4.5 V to 5.5 V limits to maintain electrical performance and prevent damage to the three-state outputs.

Part Context

This part belongs to the SN74AS257 family of quad 2-input multiplexers. It shares functional similarities with the SN74ALS257A but offers higher drive currents and faster propagation delays characteristic of the AS series. The D suffix denotes the plastic small-outline package variant suitable for surface-mount assembly techniques.

Replacement Considerations

SN74ALS257A