Tbou
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Joined: Mon Jan 24, 2022 9:42 pm

Inductor broken / MxL7704 - CM4 problem

Thu Jun 23, 2022 8:39 am

Hello,

My CM4 fell on the ground and when I picking it up I noticed that an inductor broke.

It is therefore no longer power suuply correctly. I would like to repair it because CM4s are rare, and it is also the highest configuration (8Go Ram, 32Emmc and Wifi). So I would like to ask your help to find out what is the value of the inductance? And what type of component package is it?

Mxl7704 datasheet : https://assets.maxlinear.com/web/documents/mxl7704.pdf

Best regards
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Ventran
Posts: 74
Joined: Wed Dec 16, 2020 5:22 pm

Re: Inductor broken / MxL7704 - CM4 problem

Fri Jul 01, 2022 4:34 am

Refer to the datasheet on page 27 for a typical application for this IC. You can experiment with these values. This is a good starting point. In addition, you can measure (L) the other three inductors on your board.
mxL7704.PNG
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gordon77
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Re: Inductor broken / MxL7704 - CM4 problem

Fri Jul 01, 2022 6:22 am

The setup looks similar to the pi4b, but component naming maybe different

viewtopic.php?t=318630

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mahjongg
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Re: Inductor broken / MxL7704 - CM4 problem

Fri Jul 01, 2022 12:32 pm

The white dot indicates the position of pin-1.
So in this case the rotation of the physical chip is the same as in the schematic, and the broken capacitor is indeed in the top left corner, so we are talking about L3.

Ventran
Posts: 74
Joined: Wed Dec 16, 2020 5:22 pm

Re: Inductor broken / MxL7704 - CM4 problem

Fri Jul 01, 2022 3:01 pm

mahjongg wrote:
Fri Jul 01, 2022 12:32 pm
The white dot indicates the position of pin-1.
So in this case the rotation of the physical chip is the same as in the schematic, and the broken capacitor is indeed in the top left corner, so we are talking about L3.
That's right, so the component case size is 2.5 x 2.0mm and the inductance L = 470 nH = 0.47uH. You can try to use one of these parts. The VLS252010CX-R47M-1 looks similar.
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