I would like to know the max switching frequency that one can go with ADuM4121 to drive GaN FET devices (GS66508B). Is there any Half bridge driver (low side + high side) for the same GaN devices. If possible please provide links to useful documents related to the drivers.
The ADuM4121 is recommended for operation up to 500 kHz. Above that, the quiescent current will increase at a faster rate that the linear rise below 500 kHz. You can run the part above 500 kHz, but it will have higher than expected quiescent current.
Currently, we recommend the ADuM4121 for GaN. We don't have an isolated half-bridge driver that matches GaN at the moment.