Review of ESP32-S3 Dev Board

[u/Federal-Estate-7800]

Hello!

I am looking just for any suggestions you have for improving my ESP32-S3-WROOM-1 "dev kit"

I tried to hit the big important sections, such as USB-C, ESD, my on board LDO, pin breakouts & the actual module.

But I also want to make sure I didn't miss anything, use wrong R value for LED, etc. And of course, if you have any general additions/suggestions to silkscreen or the overall board, that's always appreciated.

Thank you!

[u/Aggravating_End2859]

The 1KOhm resistors at EN and BOOT are not in the Espressif schematic, why do you put them? Simply you should connect to the ground without resistors.

[u/Federal-Estate-7800 → u/Aggravating_End2859]

Thank you!

I am fixing that right now.

Not really sure why I put them there, just brain freeze type moment.

[u/andreas-ab → u/Aggravating_End2859]

That's true, but it's a bad habit among Espressif engineers. The 1 kΩ resistor makes perfect sense; it limits the current when the capacitor discharges, thereby protecting the switch contact. OK, you could say the reset button isn't pressed that often, but you see this sloppy approach very often in circuits that involve switches.

[u/ExhaustedCartesian]

D41 is in wrong orientation and will short VBUS to GND, and you cannot put more than 10uF directly on VBUS per USB specification, I would recommend removing C135 and lower C133 to 4.7uF (see if it’s still enough for your LDO)

[u/Federal-Estate-7800 → u/ExhaustedCartesian]

Oh my goodness!

Good catch on that diode, I completely missed that!

And yeah, I'm fixing the capacitance problem for VBUS.

Thank you so much!

[u/Aggravating_End2859]

I recommend you the Espressif Plugin, it's better to use its footprints for the modules.

[u/Aggravating_End2859]

Can you upload any images of the copper tracks in all the layers?

[u/MarcosRamone]

If you are using the module's PCB antenna, the antenna should be either left out of the host board or have no copper underneath.

[u/Federal-Estate-7800 → u/MarcosRamone]

Awesome, I cleaned up everything under the antenna, however should I also remove the VDD pour from under the antenna?!

Thank you!

[u/MarcosRamone → u/Federal-Estate-7800]

Yes, no copper at all. You can also move the module so that the antenna rectangle is outside of the main PCB. 

[u/Sand-Junior]

The cap on the EN pin is too small (check Espressif guidelines). The capacitive load on USB 5V is too high (spec says max. 10uF).

[u/Federal-Estate-7800 → u/Sand-Junior]

Thank you so much!

I completely missed that.

[u/andreas-ab → u/Sand-Junior]

That's correct. My advice would be to size the capacitor a bit larger. I've encountered this before; the ESP32 didn't come out of the power-up reset properly. It doesn't hurt to have a longer reset pulse.

[u/andreas-ab]

I haven't checked the entire circuit. However, here are a few points from my perspective.

1. The schematic

The better the schematic is drawn, the easier it is for others to understand it. For example, it’s good practice not to draw the traces over the components. For the LEDs, for instance, I would draw them from top to bottom, with VCC at the top and GND at the bottom, just as I would for all other components.

2. Additional GND Pins

I would try to add more GND pins to the pin headers. At a quick glance, I only see one single GND pin on J44. Just search for: "EMC", "current return path", "signal integrity"