Evalution board

Technical Support
1

alt text

I have a quetion,Why choose (L18，L19)10A magnetic beads,Can replace with other specifications,for example 4A,6A…

2

Hi @euralxb,

Following are the basic consideration to determine the current rating of the ferrites:

  1. Selecting L18 or L46:
    The current rating of the ferrite depends upon the power supply rating.
    The power supply on the Colibri Evaluation Board is designed to provide 3.3V, 5A (16.5W) and 5V, 5A (25W) power. Total power : 41.5W.

One can use 7V-27V DC power supply to power up the evaluation board.
If a 7V DC power supply is used, the ferrite (L18 or L46) should be rated for about 6A (41.5W / 7V = 5.93A).

Considering design thumb rule, it will be good to choose a ferrite with current rating of 1.5x max. calculated current (9A).

  1. Selecting L19:
    Since return current will flow through L19, its current rating should be equal to L18 or L46 (one with higher current rating).

You should also keep the temperature v/s resistance change in mind.
Hope the explanation helps you. Feel free to contact us, if you have more questions.

Regards,
Satyan Raj