General Description

The MAX22025-MAX22028 compact isolated RS-485/

RS-422 transceivers provide 3.5kVRMS of digital galvanic

isolation between the cable-side (RS-485/RS-422 driver/

receiver-side) and the UART-side of the device. Isolation

improves communication by breaking ground loops and

reduces noise when there are large differences in ground

potential between ports. These devices allow for robust

communication up to 0.5Mbps or 16Mbps.

The MAX22025-MAX22028 feature Maxim’s proprietary

AutoDirection control making these devices ideal for

applications such as isolated RS-485 ports, where the

driver input is used in conjuction with the driver-enable

signal to drive the differential bus.

The MAX22025/MAX22027 feature reduced slew rate

drivers that minimize EMI and reduce reflections caused

by improper termination of cable allowing error-free

transmission up to 0.5Mbps. The MAX22026/MAX22028

driver outputs are not slew-rate limited, allowing

transmit speeds up to 16Mbps.

The receiver output of the MAX22025/MAX22026 does

not follow (VA-VB) when the device is in the driverenabled state. The receiver output on the MAX22027/

MAX22028 always follows (VA-VB).

The driver outputs and receiver inputs are protected

from ±10kV electrostatic discharge (ESD) to GNDB on

the cable side, as specified by the Human Body Model

(HBM). The MAX22025-MAX22028 are available in a

compact 8-pin wide body SOIC package and operate over

the -40°C to +85°C temperature range.

Applications

● Utility Meters

● Industrial Automation Equipment

● Programmable Logic Controllers

● HVAC