ESP32 Devkit custom PCB

alexander96
Posts: 12
Joined: Fri Mar 12, 2021 1:37 pm

ESP32 Devkit custom PCB

Postby alexander96 » Thu Mar 25, 2021 3:53 pm

Hello I'm trying to design a custom PCB with an ESP32WROOM-E and im pretty new into PCB development.

I tried to use an ESP32 Devkit and it worked fine so I tried to copy the Schematics found here into KICAD. https://dl.espressif.com/dl/schematics/ ... v4-sch.pdf

For my project I want to connect an RFID module and 2 RGB LED's.

As attachment you can find the schematices I tried to copy into KICAD and the stuff I added to it.

1. Are my schematics okay or are there any misstakes or things I should change? Is there any need to improve the power supply for high power usage spikes?
2. Is there a similiar product to the LESD5D5-0CT1G which I can buy on Mouser?
https://eu.mouser.com/
3. why does the AMS1117 3,3V in the schematices only has 3 Pins when in reality it has 4?

best regards Alexander
Attachments
Schematik.png
Schematik.png (35.35 KiB) Viewed 4784 times

ESP_Sprite
Posts: 8884
Joined: Thu Nov 26, 2015 4:08 am

Re: ESP32 Devkit custom PCB

Postby ESP_Sprite » Fri Mar 26, 2021 2:05 am

I think your RxD and TxD are flipped. RxD and TxD normally are indicated as the direction as seen from the device the pins are on, so you'd want to connect RxD to TxD and vice versa. The devkit flips them around in the connections of the two 0 ohm resistors; you don't.

Also, the AMS1117 is a SMD part; while it looks like it has 3 pins and a tab, it actually only has 3 pads. Flip one over if you have them lying around; the tab and the center pin actually is one large pad.

The LESD5D5-0CT1G seems to be a pretty standard 5.6V breakdown voltage TVS/ESD diode. You should be able to select for that on Mouser ad just pick any of those parts, I'd think.

alexander96
Posts: 12
Joined: Fri Mar 12, 2021 1:37 pm

Re: ESP32 Devkit custom PCB

Postby alexander96 » Fri Mar 26, 2021 10:04 am

Thats exactly why I was asking for help you are completly right. I didnt see they flipped RX and TX in the DEVKIT Schematices thank you very much.
https://www.mouser.de/ProductDetail/Com ... pBeFVHVA==
Should this ESD protection Diode work too or do I have to ask this question in a forum for the CP2102?

Best regards
Alexander

ESP_Sprite
Posts: 8884
Joined: Thu Nov 26, 2015 4:08 am

Re: ESP32 Devkit custom PCB

Postby ESP_Sprite » Sat Mar 27, 2021 5:30 am

That diode looks fine to me.

alexander96
Posts: 12
Joined: Fri Mar 12, 2021 1:37 pm

Re: ESP32 Devkit custom PCB

Postby alexander96 » Fri Apr 16, 2021 1:10 pm

Hello, I have an other question:
What does the NC stand for on the 10K(5%)(NC) Resistor used in the UART / USB Bridge?

mikeBohm
Posts: 3
Joined: Tue Sep 15, 2020 12:45 pm

Re: ESP32 Devkit custom PCB

Postby mikeBohm » Fri Apr 16, 2021 2:02 pm

alexander96 wrote:
Fri Apr 16, 2021 1:10 pm
Hello, I have an other question:
What does the NC stand for on the 10K(5%)(NC) Resistor used in the UART / USB Bridge?
NC normally stands for "Not Connected", but Im not sure what it means here, should the !SUSPENDED be grounded or not? sry

ESP_Sprite
Posts: 8884
Joined: Thu Nov 26, 2015 4:08 am

Re: ESP32 Devkit custom PCB

Postby ESP_Sprite » Sat Apr 17, 2021 3:46 am

NC in our schematics when associated with a component means the PCB will have a footprint for that component, but it's not placed there when the PCB is pick&placed (I guess it stands for No Component?) It's useful if we're not sure if there needs to be a component or not, or in case there may be a niche reason someone wants to place a component there afterwards. In practice, you can assume that component is not needed for the normal function of the devboard.

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