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Change inductor on ADL8122

Category: Hardware
Product Number: ADl8122

Hi,

i have a very similar question as in  rf amplifier .
Due to space constraints i need to change the indcutor on the input/output bias.
I would like to use a smaller component like LPS4040-684MRC with the same inductance value (680uH, also shielded) but with a higher RDC (3.0 Ohm). Is this resistance value messing with the internal biasing or would it still work ? 

Thank you!

Regards

Mqiah
 

  • Hey 

    The performance between the custom inductor value and the default inductor appears to be similar. However, I am concerned that the footprint differences between these parts may lead to compatibility issues.

    Regards,

    Dorant

  • Hi thank you for your fast reply!
    In this schematic i added the footprint for a rough comparison:

    I would design my own PCB with matching footprints if that is what you meant with compatibility issues. 

    What do you think would be the worst case if i try the following:
    I use this smaller inductor component (LPS4040 68uH), but i i introduce 0ohm jumper to use or short out the (680uH || R300ohm) and leave these components unconnected:

    pads for potential 0 ohms marked:


    In principle this should be similar to the 2nd EVAL-board with a higher lowfrequency cut (100kHz -> ~10MHz)? 

    Schematic of the 2nd version EVAL-board:

    Thank you!

    Regards 

    mqiah1

  • Based on what you proposed, the 0-ohm jumper approach appears to be a more practical and effective in this application.