MAX3085CPA

Overview

The MAX3085CPA+ is a half-duplex RS-485/RS-422 transceiver manufactured by Analog Devices (Maxim Integrated). It operates on a single +5V supply and supports data rates up to 500kbps. The device features fail-safe circuitry that guarantees a logic-high receiver output when inputs are open or shorted. It incorporates slew-rate limiting to minimize electromagnetic interference and reduce reflections on improperly terminated cables. The component includes one driver and one receiver, with a 1/8-unit-load input impedance allowing up to 256 devices on the bus. It is housed in an 8-pin PDIP package.

Feature Summary

• Fail-safe circuitry ensures a logic-high receiver output during idle or fault conditions
• Slew-rate limited drivers minimize EMI and cable reflections for reliable communication
• High input impedance allows connection of up to 256 transceivers on a single bus

Applications

• RS-422/RS-485 communications networks
• Industrial-control local area networks
• Level translators for differential signaling

Procurement Notes

Verify the specific suffix 'CPA+' against the manufacturer's current ordering information to confirm lead-free status and packaging details. Ensure the procurement channel provides valid traceability documentation. Confirm that the component matches the required temperature range and package type for the intended application environment before finalizing orders.

Selection Notes

Select this component for applications requiring half-duplex RS-485 or RS-422 communication at speeds up to 500kbps. It is suitable for environments where reduced electromagnetic emissions are critical due to its slew-rate limited drivers. Choose this part over non-limited variants if signal integrity on long or poorly terminated lines is a concern. Ensure the system operates within the specified +5V supply voltage constraints.

Part Context

The MAX3085 belongs to the MAX3080–MAX3089 family of high-speed transceivers designed for RS-485 and RS-422 standards. This family shares common features such as fail-safe operation and low quiescent current. The MAX3085 specifically targets half-duplex applications with moderate speed requirements, distinguishing it from the 115kbps and 10Mbps variants within the same series.

Replacement Considerations

Publicly confirmed pin-compatible substitutes include the MAX3485 for higher speed requirements, though electrical characteristics differ. Generic industry alternatives exist but require verification of pinout compatibility and electrical specifications against the original datasheet.