MAX3440EASA+

Overview

The MAX3440EASA+ is a fault-protected RS-485 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It operates from a single +5V supply (4.75V to 5.25V) and supports data rates up to 10Mbps with enhanced slew-rate limiting. The device features ±60V fault protection on the A and B pins, ±15kV ESD protection, and true fail-safe receiver inputs that guarantee a logic-high output when inputs are open or shorted. It includes hot-swap circuitry for telecom applications and allows up to 128 transceivers on a single bus due to its 1/4-unit-load input impedance. The component is housed in an 8-pin SO package and is specified over an automotive temperature range of -40°C to +125°C.

Feature Summary

• ±60V Fault Protection
• True Fail-Safe Receiver Inputs
• Hot-Swap Capability

Applications

• RS-422/RS-485 Communications
• Industrial Networks
• Telecommunications Systems
• HVAC Controls

Procurement Notes

Verify the specific suffix 'A' indicates the extended automotive temperature range (-40°C to +125°C). Confirm the 'SO' designation corresponds to the 8-pin Small Outline package. Ensure the '+' suffix confirms lead-free and RoHS compliance status as per manufacturer specifications.

Selection Notes

Select this model for systems requiring robust fault tolerance against high-voltage bus errors. The enhanced slew-rate limiting makes it suitable for reducing electromagnetic interference in noisy industrial environments. Verify compatibility with existing 5V logic levels and ensure the application benefits from the integrated thermal shutdown and current-limiting protections.

Part Context

This component belongs to the MAX3440E–MAX3444E family of fault-protected transceivers. While sharing core functionalities like ±60V protection and fail-safe inputs, variants within the series differ in data rate capabilities and control pin configurations. The MAX3440E specifically integrates reduced slew-rate drivers to minimize signal reflections.

Replacement Considerations

MAX3440EESA+

FAQ

How does the device handle open or shorted receiver inputs?

The MAX3440EASA+ utilizes true fail-safe receiver inputs with a differential threshold of -50mV to -200mV. This guarantees a logic-high output at RO when the A and B inputs are open, shorted together, or connected to an idle terminated line.

What is the purpose of the FAULT pin?

The FAULT pin provides a digital indication of bus faults. It goes high if the differential voltage between A and B drops below 200mV, if A or B shorts to a voltage outside the -7V to +12V common-mode range, or if A/B shorts to each other while the driver is enabled.

Does the MAX3440E support hot swapping?

Yes, the device includes hot-swap circuitry on the DE and RE control pins. This prevents false transitions on the data bus during circuit initialization or connection to a live backplane by holding the driver disabled until power-up sequences complete.