Low EMI isolated transceiver guards against large ground-to-ground differentials

Linear Technology has introduced the LTM2885, an isolated RS485 µModule transceiver for guarding against large ground-to-ground differentials. Many industrial, utility, medical, military, and intrinsic safety applications require isolation components with increased voltage and spatial separation for human safety. The device provides 6500VRMS reinforced isolation between the logic level interface and the transceiver bus pins, far surpassing the IEC 60747 basic and reinforced isolation standards. With creepage and clearance distances greater than 14mm and a distance through insulation (DTI) greater than 0.2mm, the device exceeds many overvoltage category II and material group IIIA equipment requirements, including the provision of two means of patient protection (MOPP) for medical equipment per IEC 60601-1. The device provides an extensive feature set to support its robust isolation. A ±15kV ESD-protected RS485 transceiver operates at 20Mbps or low EMI 250kbps, with uninterrupted communication guaranteed for common mode transients up to 50kV/µs. An internal low EMI DC-DC converter powers the transceiver and provides an isolated 1W supply output for powering external support components. Integrated selectable termination allows cables to be properly terminated, with the flexibility to add or remove termination anywhere on the bus via software control. Operating from a 5V supply, the LTM2885 requires no additional external components, providing a self-contained µModule solution for isolated RS485 serial data communications. The device is offered in commercial, industrial and automotive versions, supporting operating temperature ranges from 0C to 70C, –40C to 85C, and –40C to 105C, respectively. It is offered in a 22mm x 9mm x 5.16mm surface mount BGA package; all integrated circuits and passive components are housed in the company’s RoHS-compliant µModule package.