FEDEVEL
Platform forum

HACKhalo2 , 07-01-2025, 02:00 PM

So I'm working out how to design my first board with the help of both the Fedevel channel and a few more Youtubers, and I think I got a decent grasp on how it should be done, but I want to have more knowledgeable people look at it before I send it out for the first round of fabrication.

This is a 45mmx50mm ESP32-WROOM-32E based IMU tracker, on a 4 layer PCB. It's communicating with the ICM45686 IMU and LIS2DML 3D Mag over SPI with an admittedly overbuilt SPI circuit. It's going to be powered primarily by a battery (most likely a 804040 or similar) and uses USB-C for data communication to the ESP through the CH341, and charging through the TP4056 set to 1A charging (which the 804040 should happily handle).

Layer 1 is where all the things live.
Layer 2 is the Ground Plane with minimal traces for SPI data
Layer 3 is where all the power is routed and a mesh Ground plane to take up the rest of the space.
Layer 4 is the rest of the data traces.

Ground/Power traces are 0.5mm wide. most of the other traces are 0.254mm wide. the USB data traces are length matched to within 0.5mm and are 0.2mm wide

QDrives , 07-01-2025, 10:21 PM

Do not place traces on your Gnd layers. There is plenty of space on the other layers.
Have the Gnd layer next layer to the USB traces.
Do not route traces on the top underneath the USB connector. It is metal and solder mask is **not** an insulator.
Why the muxes? You have 2 CS lines and 2 outputs on the ESP.
For U3 check the note below the schematic in the datasheet.