MAX3085EPA

Overview

The MAX3085EPA+ is a half-duplex RS-485/RS-422 transceiver manufactured by Analog Devices Inc./Maxim Integrated. It operates from a single +5V supply and supports data rates up to 500kbps with slew-rate-limited drivers. The device features fail-safe circuitry that guarantees a logic-high receiver output when inputs are open or shorted. It incorporates ±15kV ESD protection on the bus lines and utilizes a 1/8-unit-load receiver input impedance, allowing up to 256 transceivers on the bus. The component is housed in an 8-pin PDIP package and functions within a temperature range of -40°C to +85°C.

Feature Summary

• Slew-rate-limited driver outputs minimize electromagnetic interference (EMI) and reduce signal reflections caused by improperly terminated cables.
• Integrated fail-safe circuitry ensures a logic-high receiver output state when differential inputs are open, shorted, or disconnected.
• Enhanced electrostatic discharge (ESD) protection rated at ±15kV on the A and B bus pins.

Applications

• RS-422 and RS-485 communication networks
• Industrial control local area networks
• Level translation applications

Procurement Notes

Verify the specific ordering suffix against official documentation to confirm package type and temperature grade. Ensure the component matches the required half-duplex configuration and 500kbps data rate specifications for the target design.

Selection Notes

Select this component for designs requiring high-speed transmission up to 500kbps with reduced EMI characteristics. It is suitable for systems needing robust fault tolerance and high noise immunity via fail-safe thresholds and ESD protection.

Part Context

This part belongs to the MAX3080–MAX3089 family of high-speed transceivers. Within this series, the MAX3085 is specifically designated for half-duplex operation with a 500kbps maximum data rate capability.

Replacement Considerations

Publicly confirmed pin-compatible substitutes include the SN65HVD3082 and AZRS485E.

FAQ

What is the fail-safe threshold voltage for the MAX3085?

The receiver threshold is set between -50mV and -200mV. If the differential input voltage (A-B) is greater than or equal to -50mV, the output is logic high; if less than or equal to -200mV, it is logic low.

How many transceivers can be connected to the bus using the MAX3085?

Due to its 1/8-unit-load receiver input impedance, up to 256 MAX3085 transceivers can be connected in parallel on a single communication line.

Does the MAX3085 support full-duplex operation?

No, the MAX3085 is designed specifically for half-duplex communications. Full-duplex variants in this family include the MAX3080, MAX3081, MAX3083, MAX3084, MAX3086, and MAX3087.