We are using ADuM1401BRWZ in our design on a SPI bus. Currently we are able to read and write data at 4MHz clock. When we increase the clock speed to 8MHz we are unable to get the proper data. As per the part no ADuM1401BRWZ is supposed to operate till 10Mbps datarate. Please suggest whether any modifications is required or anyone faced the same issue in there design.