Low EMI, isolated RS485 µModule transceiver to IEC 60601-1

November 16, 2016 // By Graham Prophet
LTM2885 is an isolated RS485 µModule (“micromodule”) transceiver for guarding against large ground-to-ground differentials for safety in industrial, utility, medical, military, and intrinsic safety applications that require isolation components with increased voltage and spatial separation.

 

The device provides 6500 VRMS 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 14 mm and a distance through insulation (DTI) greater than 0.2 mm, the LTM2885 exceeds many overvoltage category II and material group IIIA equipment requirements, including the provision of two means of patient protection (MOPP) for medical equipment according to IEC 60601-1.

 

The LTM2885 provides a feature set that includes ±15 kV ESD-protected RS485 transceiver operating at 20 Mbps or low-EMI 250 kbps, with uninterrupted communication guaranteed for common mode transients up to 50 kV/µsec. 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 LTM2885 is offered in commercial, industrial and automotive versions, supporting operating temperature ranges from 0°C to 70°C, –40°C to 85°C, and –40°C to 105°C, respectively. The LTM2885, in a 22 x 9 x 5.16 mm surface mount BGA package, costs $11.98 (1,000).

 

Linear Technology; www.linear.com/product/LTM2885