MAX22027AWA+

Overview

The MAX22027AWA+ is a compact, isolated half-duplex RS-485/RS-422 transceiver featuring Maxim’s proprietary AutoDirection control. It provides 3.5kVRMS of digital galvanic isolation between the UART side and cable side. The device supports data rates up to 0.5Mbps with slew-rate limited drivers to minimize EMI. It operates over a temperature range of -40°C to +85°C in an 8-pin wide body SOIC package.

Feature Summary

• Integrated AutoDirection control eliminates the need for separate driver-enable and receiver-enable signals by using an internal state machine.
• Slew-rate limited drivers reduce electromagnetic interference (EMI) and minimize reflections caused by improper cable termination.
• Receiver output always follows the differential bus voltage (VA-VB), allowing the RXD pin to reflect actual line states during transmission.
• Built-in protection includes ±10kV electrostatic discharge (HBM) on driver outputs and receiver inputs.

Applications

• Utility Meters
• Industrial Automation Equipment
• Programmable Logic Controllers
• HVAC Systems

Procurement Notes

Verify the component authenticity through official Analog Devices channels or authorized distributors. Confirm the specific suffix 'AWA+' corresponds to the RoHS-compliant 8-pin Wide SOIC package variant. Ensure the procurement documentation matches the exact part number to avoid confusion with non-isolated or different speed variants within the MAX22025-MAX22028 family.

Selection Notes

Select this model when designing systems requiring simplified half-duplex communication without external DE/RE control logic. The MAX22027 is appropriate for applications prioritizing low EMI emissions due to its reduced slew rate, unlike the MAX22028 which supports higher speeds. Verify that the system ground potential differences do not exceed the 3.5kVRMS isolation rating.

Part Context

This component belongs to the MAX22025-MAX22028 family of isolated transceivers. While sharing the same isolation barrier and package, it differs from the MAX22028 by having a lower maximum data rate of 0.5Mbps and utilizing slew-rate limiting. It also differs from the MAX22025/MAX22026 series by ensuring the receiver output tracks the bus voltage even when the driver is active.

Replacement Considerations

The MAX22028AWA+ serves as a high-speed alternative if the 16Mbps capability is required, though it lacks slew-rate limiting. For non-isolated applications, standard RS-485 transceivers may be used but will require external isolation components. No direct drop-in replacements exist for other manufacturers offering identical integrated isolation and AutoDirection features.