SN65DSI83EVM: SN65DSI85 EVM Schematic powerline filter ferrite bead selection

Hari-san

This came from the Murata datasheet, https://www.murata.com/en-us/products/productdata/8796747366430/ENFA0021.pdf. We are using BLM18EG221SN1D.

You can use the capacitor with voltage rating of 10V.

Thanks

David

Hi David,

Thank you very much.

My question is how to select that impedance at frequecny. I mean why you choose 220 Ohms @ 100 MHz.

Why not 100 Ohm @ 50Mhz.

Regards

HARI

Hari

The 220ohm@100MHz is part of the bead spec, but you should look for its impedance vs. frequency plot as shown below. We want to suppress noise around 400-500MHz and this bead fits our need.

For selecting the ferrite bead, please take a look at this link, https://www.allaboutcircuits.com/technical-articles/choosing-and-using-ferrite-beads/.

Thanks

David

Hi David-San,

Thank you very much.

One last question. Please don't feel bad.

May I know from where you got you need to , suppress noise around 400-500MHz and this bead fits our need.

Regards

HARI