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Original question:

DP83822I: Any part number recommendation for DC blocking capacitors 33nF ?

DP83822I: Transformerless design for PHY to PHY connection

AIO
Prodigy 40 points

Part Number: DP83822I

Hi,

I would like to connect the DP83822IRHBR to the DP83825IRMQR which are interfaced with eachother over the TP_P/M & RD_P/M.

I would like to do this transformerless with the help of capacitors, but the value for the capacitor is not clear to me. The application note "AN-1519 DP83848 PHYTER® Transformerless Ethernet Operation (Rev. A) " uses 33nF but in the following forum post: https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1529808/dp83822i-any-part-number-recommendation-for-dc-blocking-capacitors-33nf?tisearch=e2e-sitesearch&keymatch=DP83822I%25252520TRANSFORMER#

It is said the specification for the DP83822IRHBR capacitor has changed for 33nF to 100nF, but this is not reflected in the datasheet of the PHY.

 

Could someone please help confirm which value capacitor is advised/tested.

 

  • 0
    TI__Mastermind 37385 points

    Hi,

    I recommend proceeding with the 33nF capacitor value as this has been tested extensively in our app note. The 100nF value should work as well if you need a higher Vrms rating, however this should be tested in your system to be certain.

    Best,

    Shane