Galvanic isolation technology enables signal solutions

3rd May 2018

Lanna Deamer

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The availability of a new galvanic isolation process technology that enables the fabrication of robust and reliable high voltage signal isolation solutions, has been announced by X-FAB Silicon Foundries. According to the company, the new process achieves best-in-class isolation performance. By leveraging it, X-FAB’s customers will be able to design their own capacitive or inductive couplers for a wide range of applications.

Galvanic isolation electrically separates two circuits in order to improve noise immunity, remove ground loops, increase common mode voltage and safely isolate high voltages.

Traditionally, optocoupler technology has been used to provide single-package signal isolation between two circuits in a system. However, for high temperature, high speed, high reliability or multi-channel systems, chip-level galvanic isolation based on capacitive or inductive coupling is more appropriate and cost efficient compared to an optocouplerapproach.

The 12VDC auxiliary systems in electric vehicles require galvanic isolation from the hundreds of volts powering the vehicle’s traction systems in order to protect against ground loops, signal noise and the risk of dangerous electric shocks.

Another common application is medical diagnostic equipment, where it is important to safely isolate the electronic circuitry - which is plugged into the AC mains - from the low voltage sensor element that is in contact with the patient’s skin.

Power supplies such as DC/DC converters and switched-mode converters also need cost effective high voltage isolation to ensure proper voltage regulation and reliability is maintained, as well as operator safety.

X-FAB now offers galvanic isolation technology on a foundry basis for robust and reliable couplers that need to withstand high voltages. For companies interested in the new galvanic isolation technology, the company offers packaged evaluation samples. Both packaged single-channel inductive and capacitive coupler samples are available.

The capacitive coupler test chip, designated G3-C1, with an isolation layer thickness of 11µm and was able to withstand up to 6,000Vrms, the maximum limit of the test setup. Isolation layers thicker than the test chip’s 11µm are also available if a higher withstand voltage is required.

The new isolation process technology has been developed at X-FAB’s Dresden manufacturing site which is now certified for automotive manufacturing according to the new IATF-16949:2016 International Automotive Quality Management System (QMS).