SN74ALS243ANSR

Overview

The SN74ALS243ANSR is a quadruple bus transceiver from the Texas Instruments ALS logic family, designed for asynchronous two-way communication between data buses. 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 dual output-enable inputs (OEAB and OEBA) that control data flow direction or isolate the buses. Propagation delay ranges from 4 ns to 11 ns depending on load conditions.

Feature Summary

• Dual-enable configuration allows flexible timing control for data transmission between A and B buses.
• Capability to store data by simultaneously enabling both control inputs to latch states.
• P-N-P input structure reduces DC loading on driving circuits.

Applications

• Asynchronous two-way communication between data buses
• Bus-oriented memory and command decoders
• Input/output buffering

Procurement Notes

Verify component status as the SN74ALS243ANSR is listed as obsolete in official documentation. Confirm availability of alternative packages such as SOIC-14 or PDIP-14 if surface-mount sourcing is restricted. Ensure design reviews account for discontinued status before finalizing procurement plans.

Selection Notes

Select this component when designing systems requiring bidirectional bus isolation with latching capability. Verify that the required propagation delay meets system timing constraints under specific load capacitance. Consider the obsolete status and evaluate equivalent active parts from the same logic family for long-term supply stability.

Part Context

This device belongs to the SN74ALS243A series, which includes variants like SN74ALS243AD and SNJ54ALS243AFK. The 'N' suffix typically denotes plastic DIP packaging, while 'D' indicates SOIC. The 'SR' suffix often implies tape-and-reel packaging, though specific package details for this exact suffix should be cross-referenced with current TI ordering guides.

Replacement Considerations

SN74ALS243AD

FAQ

How does the device handle data storage?

Data can be stored by simultaneously enabling both OEAB and OEBA inputs, causing the outputs to reinforce their inputs and retain the state of the bus lines.

What is the function of the OEAB and OEBA inputs?

These dual output-enable inputs control the direction of data transmission between the A and B buses or place the outputs in a high-impedance state for isolation.