ADIS16209 power supply

Hello

Our customer will use ADI16209 and he selects ADP1712 as FAQ: ADIS1620x/21x/22x Power Supply Considersations.

https://ez.analog.com/docs/DOC-11900

Our customer's test result was that ADP1712 with external 2uF outputs rush current of ~2A peak at start-up.

If Wattage ( themal problem ) is little,   is not there any problem with rush current ?

Or does  the test at https://ez.analog.com/docs/DOC-11900 include external component to protect  against  rush current ?

Regards,

Terumasa

  • 0
    •  Analog Employees 
    on Nov 13, 2017 6:27 PM over 3 years ago

    Thank you for your post and for your support!  If your customers is observing a peak current of 2A, then they must have a very fast ramp time on their supply (3.3V in ~3.3us).  Why does this need to be so fast?  While we do recommend quick and clean transitions, I would think that this could be in the 50-100us region and still work fine.   Of course, we always recommend thorough testing in the final configuration.

    On your question (below), I would recommend that any limitations be clearly defined, before we trying to determine what to do about these limitations.  If there is a limitation in the "wattage" of the power supply, what is that limitation? 

    • If Wattage ( themal problem ) is little,   is not there any problem with rush current

    Given the relatively low energy that is put into the 2uF capacitor, I would not anticipate thermal issues, unless the customer has extremely thin wires or traces.  I would probably concern myself with the current limit threshold and recovery behaviors of the customer's power supply, in order to make sure that this does not cause instability or other strange response characteristics (which could be damaging, per device absolute maximum ratings in the datasheet).

    I hope that this helps!

    Thanks again!

  • Hello NevadaMark,

    Thank you for your asnwer.

    Regards,

    Terumasa

  • 0
    •  Analog Employees 
    on Nov 14, 2017 6:04 PM over 3 years ago

    You are welcome! Glad that this helped.