Ferrite bead for Ublox MAX-M10S (GPS)

Community PCB Design
1

Hi!

I am trying to figure out the exact ferrite bead used in the schematic for the SparkFun GNSS Receiver Breakout - MAX-M10S (Qwiic). The schematic calls for a 2.66 Ohm ferrite bead on the power line for the active GPS antenna (VCC_RF). However, I am not sure how to find out the same or comparable component in Digikey. Most SMD ferrite beads show impedance at resonant frequency and most of them are at 100Mhz. My understanding is that the purpose of the ferrite bead is to minimize (filter out) the noise from the device feeding the power into the antenna line (which can cause noise). In this case, its the Ublox M10S GPS module.

Does that mean that I am looking to filter out the frequency of the GPS clock specifically with the Ferrite bead? I cannot seem find what that frequency would be.

I am not sure if I am looking for a 2.66 Ohm @ 100Mhz or something else. The Eagle files don’t seem to show a specific model for this component either.

Product:

https://www.sparkfun.com/products/18037

Any help would be appreciated.

Thanks

2

You need to look at page 42 the Integration Manual, which is linked to from the documents tab.

It suggests one of these:

  • Murata LQG15H, LQW15A series

  • Johanson Technology L-07W series

  • Any other inductor with impedance >500 Ω at GNSS frequency and current rating above 300 mA.