SN74ALS258AN

Overview

The SN74ALS258AN is a quad 2-input multiplexer with 3-state outputs manufactured by Texas Instruments. It operates within a supply voltage range of 4.5 V to 5.5 V and supports an operating temperature range of 0°C to 70°C. The device features low-level input current of -0.1 mA and high-level output current capability of -2.6 mA. Propagation delays from data inputs (A or B) to output (Y) range from 2 ns to 9 ns, while select line (A/B) delays range from 5 ns to 25 ns. Enable/disable times vary between 2 ns and 37 ns depending on the transition direction.

Feature Summary

• Multiplexes signals from four independent 2-bit data sources to four corresponding output lines for bus-organized systems.
• Provides three-state outputs that isolate data lines when the output-enable input is at a high logic level.
• Interfaces directly with system buses without loading the data lines during disabled states.

Applications

• Multiplexing signals from multiple sources in high-performance systems
• Bus interface applications requiring direct connection to system buses
• Data selector circuits in digital logic designs

Procurement Notes

Verify the specific ordering suffix 'AN' corresponds to the standard plastic DIP package configuration. Confirm the manufacturer identification as Texas Instruments through official documentation. Ensure the component meets the specified commercial temperature range requirements for your application environment before integration.

Selection Notes

Select this component for applications requiring quad 2-to-1 multiplexing with tri-state output control. Consider the ALS technology for balanced speed and power consumption compared to standard TTL. Verify that the required operating temperature range aligns with the commercial specification limits defined in the datasheet.

Part Context

This part belongs to the SN74ALS series of advanced low-power Schottky logic devices. It functions as a data selector/multiplexer designed for bus-organized systems. The device is distinct from the SN54 variant which supports military temperature ranges, and differs from the AS series which offers higher drive currents and faster switching speeds.

Replacement Considerations

SN74ALS257A is functionally similar but lacks the 3-state outputs found in the SN74ALS258A. SN74AS258A provides enhanced performance characteristics including higher output current and reduced propagation delays while maintaining the same logical functionality and pinout compatibility.

FAQ

How does the output-enable input affect the data lines?

When the output-enable (OE) input is at a high logic level, the three-state outputs do not load the data lines, effectively isolating them.

What is the difference between the A/B select input and the A or B data inputs?

The A/B input acts as the select line to choose between the two data sources (A or B) for each channel. The A and B inputs are the actual data lines being multiplexed.