Author Topic: AMS1117 3.3 and ESP32 circuits - help  (Read 2809 times)

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Offline PGPG

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Re: AMS1117 3.3 and ESP32 circuits - help
« Reply #75 on: November 29, 2024, 09:46:11 am »
Seems that only practice will help me to become better ...

Exactly!
The number of burned/exploded items decreases with practice :)

As we are not able to assemble ourselves small elements (like 2x2mm MEMS IC with 12 pads hidden under it) we not make prototypes of PCBs I design. We start from ordering a production serie of 100 pcs.

This is different world than software were you can fix bug after bug. In our world if you not get the 100% bug free solution in the first shot you pay dearly for it.
 

Offline tooki

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Re: AMS1117 3.3 and ESP32 circuits - help
« Reply #76 on: November 30, 2024, 12:58:58 pm »
I also added two 20p capacitors on USB Data lines.
Why would you do that!?!

Capacitance on USB data lines is something to be minimized, not added to!

For USB 1.1 speeds, 20pF is the maximum allowed, for USB 2.0 speeds, the maximum is just 4pF.

What you want to do is protect the port with TVS diodes, and those for USB are specially selected to have low capacitance.

See https://www.ti.com/lit/an/slvaf82b/slvaf82b.pdf
« Last Edit: November 30, 2024, 01:00:49 pm by tooki »
 


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