RS-485 Transceivers

ADM2483BRWZ-RL7

ADM2483BRWZ-RL7 - Isolated RS-485 Transceiver | Analog Devices

The ADM2483BRWZ-RL7 is a half-duplex, galvanically isolated RS-485 transceiver from Analog Devices, integrating a 3-channel digital isolator, a three-state differential line driver, and a differential input receiver in a single 16-lead SOIC-W package. It is designed for bidirectional data communication on balanced, multipoint bus transmission lines and complies with ANSI TIA/EIA RS-485-A-1998 and ISO 8482:1987(E). The device operates from a 5V or 3V logic supply (VDD1) and a 5V bus supply (VDD2), supporting data rates up to 500 kbps with slew-rate-limited driver outputs to minimize EMI. Key specifications include a 2500Vrms isolation rating, common-mode transient immunity greater than 25 kV/µs, and a low quiescent current of 2.5 mA maximum. The ADM2483BRWZ-RL7 is available in tape and reel packaging, making it suitable for high-volume production. An isolated RS-485 transceiver is a device that combines an RS-485 physical layer transceiver with galvanic isolation between the logic side and the bus side. It is a key component in industrial communication networks, where it provides a robust, noise-immune interface over long cable runs while protecting sensitive control electronics from ground potential differences, surges, and transients. The isolation barrier is typically implemented using capacitive or magnetic coupling, as in Analog Devices' iCoupler technology, which offers superior performance compared to optocoupler-based solutions in terms of speed, power consumption, and reliability. Key features of the ADM2483 include true fail-safe receiver inputs that guarantee a logic-high output when the bus is open, shorted, or idle, and chatter-free power-up/power-down protection that prevents spurious data during power cycling. The device supports up to 256 nodes on a bus, making it suitable for large multi-drop networks. Thermal shutdown protection prevents damage from excessive power dissipation. The wide operating temperature range of -40°C to +85°C ensures reliable operation in harsh industrial environments. Technically, the ADM2483 uses iCoupler technology, which employs chip-scale transformers to transmit data across the isolation barrier, providing high common-mode transient immunity and reliable operation at high data rates. The driver outputs are slew-rate limited to reduce radiated emissions, and the receiver has a wide common-mode input range of -7V to +12V, accommodating large ground potential differences. The device is available in a 16-lead SOIC-W package, which is compact and suitable for space-constrained designs. Typical applications include industrial fieldbus networks, building automation, HVAC systems, motor control, and remote data acquisition systems. The ADM2483 is ideal for applications requiring robust, isolated RS-485 communication over long distances, such as factory automation and process control. When designing with the ADM2483, it is important to provide proper decoupling on both VDD1 and VDD2, and to ensure that the bus termination resistors are correctly placed to match the cable impedance. The isolation barrier should be maintained with adequate creepage and clearance distances on the PCB to meet safety standards.