A transformer-based digital isolator with 20kVPK surge capability and > 200kV/µS Common Mode Transient Immunity

Abstract

This paper presents a transformer-based digital isolator that achieves best-in-class robustness with 20kV <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PK</inf> surge capability and > 200kV/µS Common Mode Transient Immunity (CMTI). Using polyimide as insulation material, the isolation barrier is more than 30µm thick and enables the exceptional surge performance. The transformer is fully differential with symmetric layout to improve noise immunity. The OOK Transmitter (TX) is based on the negative-G <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</inf> oscillator and operates in the voltage-limited domain. It enable the TX to keep generating the differential On-Off Keying (OOK) carrier signal during disturbances from very fast Common Mode Transient (CMT) noise.