ISOW7841: DESIGN CONSIDERATION TO AVOID RADIATED EMISSION

Part Number: ISOW7841

I want to useISOW7841 digital isolator in my project .But i want to know that will it make any radiation effects in the board??.

This isolator is used in one daughter board ,which is used to measure both current and voltages. This board is having 32 isolated channels,processors and power supplies,etc. The board dimension is 125mm * 85mm. the components are almost tightly packed on the top and bottom layers. The isolators will be on both layers. The daughter board will be plugged in the main board ,both boards will have 10mm gap.Both board will communicates through FMC-HPC Connector.

Is it make any radiation problems in the board itself or in the main boar?

what are precautions should I take to avoid the radiated emission ?

Please help me to get the best design

1 Reply

  • Hello,

    My experience is that you may experience radiated emissions originating at the ISOW7841, especially if your device has cables attached.
    I have had to revise a board to add EMC filtering to the ISOW7841 supplies and to all the cable connections to address radiated emissions from the cables at harmonics of the ISOW7841 power supply operating frequency.

    The product failed CISPR11 level B, all the failure points were related to the ISOW7841.

    You should read application note SLLA368A and follow the advice there. I have used the scheme shown in Figure 13 with a Y2 capacitor as shown in Figure 7, but I have not implemented the overlapping planes proposed in Figure 8; that would be difficult on my board.

    I will test my new board next week....