ADuM3070 Output Load Ripper Question

Dear Sir:

If I need ADuM3070 DC-DC ISO Power Vin:5V,Vout 5V/300mA but output ripper need VP-P 100mV. I have some question pls see below.

Q1:Can you provide your suggestion in my schematic design and PCB Layoutent.another How do I achieve his idea on the EVAL-ADuM3070EBZ EVB Board?

Q2:EVAL-ADuM3070EBZ PSRR is how much,?

Best Regards,

Jacky

  • 0
    •  Analog Employees 
    on Apr 26, 2013 1:04 AM

    Jacky:  My answers to the 2 questions:

    Q1: The ADuM3070 circuit on the evaluation board EVAL-ADuM3070EBZ will meet your requirement for 5V in to 5V out at 300Ma with output ripple of 100mVpp.  The figure 27 in the datasheet shows the ripple is from about 4.98 to 5.02V for about 50mV ripple, with also some noise spikes picked up by the ground loop on the scope probe measurement that look higher than this.  But if you look at the ADuM347x datasheet, which has the same circuits measured with a small ground lead, and with the same layout on the eval board, figure 34 shows the ripple is really only from 4.98 to 5.02V, for a 20MHz bandwidth. If you need less ripple you can add some more filtering, a small ceramic capacitor of  0.1 to 1.0uF close to the load will reduce the spikes.

    Q2:We don't have a specification for PSRR, and I did not find one when I looked at other solutions, but if you have a target PSRR please let me know. Power supply rejection from the primary supply to the isolated supply should be very good due to the transformer isolation and integrated isolated feedback. We do specify the line rejection of 1mV/V typical and 10mV/V max for a 50mA load.

    Regards, Brian

  • 0
    •  Analog Employees 
    on Aug 2, 2018 4:49 PM
    This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

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