B404X Schematic Questions


I am making a custom PCB base board for the B404X.

  1. Does the B404X come with any power supply circuitry such as a buck converter (regulator for supplying the 3.3V), a battery charging circuit, a fuel gauge, a LiPo connector, or a power switch? The Boron contains all of the above but the M.2 SOM eval board does not.

  2. Also, on the M.2 SOM eval board what are the three U.FL connectors on the bottom of the schematic?

  3. On the M.2 SOM eval board, What is the inductor L1 for?

No, the B404X B-SoM does not include a 3.3V regulator, PMIC, fuel gauge, or charger. None of the Particle M.2 SoMs include those components, they are expected to be on your base board if you need them.

The M.2 eval board does have all of those components, as does the Boron BRN404X.

The left U.FL connector is for NFC (present on B-SoM, but not M-SoM). The B-SoM does not have a U.FL for NFC on the SoM itself.

The two other connectors are the spots for the SMA to U.FL adapters that come with the M.2 eval board. They're not electrically connected to anything on the M.2 eval board; they're just the PTH solder footprint for soldering in the SMA adapter if you want to use it.

L1 is a 0603 30 ohm ferrite bead (GZ1608D300TF) that connects GND (system ground) to AGND (analog ground). You could just tie them together. AGND is only used on the B-SoM, not the M-SoM.

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Thank you!