Looks nice!
Some questions/comments:
- choosing to use the bare ESP32 IC is a bold move, because that means you have to seek regulatory certification yourself for the radios. (One of the big advantages of using an ESP32 module is that they’re already certified worldwide.)
- why USB mini-B and not USB-C?
- what are the two different Ethernet port versions?
- the datasheet has a typo, the RTC crystal should be 32.768kHz, not 32.758kHz.
Thank you for your comments and pointing out the error in the datasheet.
I used micro USB since it is cheaper, and I have lots of them at my office. But USB-C is a good idea. I can use it when I make a second revision.
There are two boards with the same functionality in this project. One has components for a temperature range of -40 to +85 °C. That one has a more expensive Ethernet connector. The other board design is for 0 to 70 °C and I used a lower priced connector.
You are right about the certification, but I personally don't prefer to use modules instead of bare MCUs. Even I used it, I would need to get a certification for the whole product. I can say that the ESP32 Ethernet modules on the market are very susceptible to both radiated and transient emissions. The main goal of this design was having a robust ESP32 Ethernet module to use for my projects.
And there is another purpose. After I decided to do an open source design, I wanted to contribute more by not using a module and by doing the PCB antenna design from scratch for this board. ESP32 modules' PCB antennas are not that good, and I thought there was a room for an improvement.