MAX3085EESA+

Overview

The MAX3085EESA+ is a half-duplex RS-485/RS-422 transceiver in an 8-pin SOIC package. It operates from a single +5V supply and supports data rates up to 500kbps with enhanced slew-rate limiting. The device features ±15kV ESD protection on all I/O pins and fail-safe circuitry that guarantees a logic-high receiver output when inputs are open or shorted. It draws 600µA of supply current under typical conditions and functions within an industrial temperature range of -40°C to +85°C.

Feature Summary

• Enhanced slew-rate limiting minimizes electromagnetic interference (EMI) and reduces signal reflections caused by improperly terminated cables.
• Fail-safe receiver circuitry ensures a logic-high output state when the differential receiver inputs are left open, shorted, or connected to a terminated bus with disabled drivers.
• Integrated ±15kV electrostatic discharge (ESD) protection on all transmitter outputs and receiver inputs using the Human Body Model.

Applications

• RS-422 and RS-485 communication networks
• Industrial control local area networks
• Transceivers for applications requiring EMI sensitivity mitigation

Procurement Notes

Verify the component against official Analog Devices documentation to confirm pinout compatibility and electrical specifications. Ensure the operating environment remains within the specified -40°C to +85°C temperature range. Confirm that the system power supply adheres to the required +5V tolerance for proper functionality.

Selection Notes

Select this component for half-duplex applications requiring transmission speeds up to 500kbps. It is suitable for environments where reduced EMI is critical due to its specific slew-rate limitations. Verify that the bus topology supports the 1/8-unit-load receiver input impedance, allowing for extensive network expansion.

Part Context

This device belongs to the MAX3080E–MAX3089E family of high-speed transceivers designed for RS-485 and RS-422 standards. While sharing common ESD protection and fail-safe features with the series, the MAX3085E specifically targets half-duplex operations with intermediate speed capabilities compared to the 115kbps and 10Mbps variants.

Replacement Considerations

The datasheet indicates pin compatibility with the industry-standard 75180 transceiver. Designers should verify that any substitute component matches the specific 500kbps slew-rate characteristics and half-duplex configuration required by the MAX3085E.

FAQ

What is the fail-safe behavior of the MAX3085E receiver?

The receiver guarantees a logic-high output when the inputs are open, shorted, or connected to a terminated line with all drivers disabled. This occurs because the threshold is set between -50mV and -200mV.

How does the MAX3085E handle electromagnetic interference?

It utilizes enhanced slew-rate limiting to minimize EMI and reduce reflections caused by improperly terminated cables, facilitating error-free data transmission at speeds up to 500kbps.

What is the maximum number of transceivers supported on the bus?

The device features a 1/8-unit-load receiver input impedance, which allows up to 256 transceivers to be placed on the bus simultaneously.