Foundry galvanic isolation process for high voltage chips
The new process allows X-Fab customers to design their own capacitive or inductive couplers for a wide range of applications. A capacitive coupler test chip has an isolation layer thickness of 11 µm and is able to withstand up to 6,000 Vrms, the maximum limit of the test setup. Isolation layers thicker than the test chip’s 11 µm are also available if a higher isolation voltage is required.
The 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).
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 12 VDC 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.
For companies interested in the new galvanic isolation technology, the company offers packaged evaluation samples as the G3-C1 test chip. Both packaged single-channel inductive and capacitive coupler samples are available.
Galvanic isolation design kits are available for all major EDA platforms and can be downloaded from X-FAB’s customer portal. Samples can be supplied on request. These chips are for evaluation purposes only and are not available for commercial resale.