(ADuM4120)How did you improve isolation voltage?

Hi !

I was checking ADuM4210 datasheet.

http://www.analog.com/media/en/technical-documentation/data-sheets/ADuM4120-4120-1.pdf 

Also I was checking ADuM4233 datasheet.

http://www.analog.com/media/en/technical-documentation/data-sheets/ADuM3223_4223.pdf 

This is from ADuM4120 datasheet.

This is from ADuM4223 datasheet.

How did you improve the isolation voltage?

Did you change the isolation barrier?

Best regards.

Kawa