ADuM4070 - Setting Fsw to 120kHz with Roc = 510kohm -  What are the implications of setting

200kHz > Fsw < 1MHz according to data sheet, but EMC problems fixed by reducing Fsw. Initial trials satis but what are the reliability issues arising?

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    •  Analog Employees 
    on Jan 24, 2018 1:18 AM

    UKFAE: I heard back from the designer on your request

    I think it would be fine for ADuM4070 to operate at 120kHz. The internal circuit will support this low switching frequency. However, the customer must be careful when designing the DC/DC converter. For example, a bigger inductor would be preferred to limit the peak current and limit the loop bandwidth.

    Also I think the electrical parameters in the datasheet might not be guaranteed. The customer might be characterizing the converter by themselves.

     

    Alternatively, there are techniques that can help reduce emissions when using the ADuM4070, which include the use of a safety capacitor from GND1 to GNDISO, and the use of RC snubbers as seen on the attached circuit.

     

    Regards, Brian

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  • 0
    •  Analog Employees 
    on Jan 24, 2018 1:18 AM

    UKFAE: I heard back from the designer on your request

    I think it would be fine for ADuM4070 to operate at 120kHz. The internal circuit will support this low switching frequency. However, the customer must be careful when designing the DC/DC converter. For example, a bigger inductor would be preferred to limit the peak current and limit the loop bandwidth.

    Also I think the electrical parameters in the datasheet might not be guaranteed. The customer might be characterizing the converter by themselves.

     

    Alternatively, there are techniques that can help reduce emissions when using the ADuM4070, which include the use of a safety capacitor from GND1 to GNDISO, and the use of RC snubbers as seen on the attached circuit.

     

    Regards, Brian

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