XCore Exchange

Marc, thanks for the screen shots. They are keepers for all developers to observe. Wow !!

Really suggest to review the AP2822AK which are like under $0.10 USD each (see Avnet) in T&R qty and offer soft-start along with other features. Your EMI filter from ST can remain but there are other options. We sourced our EMI USB 2.0 and USB 3.0 filters from Kingcore (Taiwan) at great prices.

KC p/n.WCM-2012-900T
Price USD0.04/pc FOB Taiwan
SPQ=3000pcs/reel

The XMOS in rush solution should also work but if you consider the required number of SMT placements, it is a lower cost to consider a single device for VBUS protection than multiple discretes.

Another great partner we use for EMI filters, inductors is Max Echo in Taiwan. Have used them for years with great success. Looking forward in hearing about your success with a fresh board. In light of this VBUS issue, believe it will work as you expect.

Actually the AP2822AK is more like $0.15/1K in stock (Avnet has none) https://octopart.com/search?q=AP2822AK

The ST part has EMI as well as ESD protection, so I favor that over a simple coil.

Funny because I had the 10KΩ series resistor in the first rev then took it out... guess I'm putting it back!

https://www.avnet.com/shop/us/p/power-m ... 625072446/

https://www.digikey.com/products/en?key ... IDKR-ND%20

For our designs, we use the Socay (Shenzhen - they OEM to many key industry players) ULC0524P ESD transient suppressor which offers higher level of protection than the ST device and then the Kingcore EMI filter.

http://www.socay.com/upfile/201407020248027678.pdf

C61000-4-2 (ESD) ± 15kV (air), ±8kV (contact)
C61000-4-4 (EFT) 40A (5/50ns) ; not listed on the ST component
C61000-4-5 (Lightning) 5A (8/20μs) ; not listed on the ST component

old thread but just to close it out. Turns out some kind of latch-up. once the unit was powered off for like a week or 2, it came back to life and worked fine! For my prototypes, I just put a 5.1V zener on that line to keep it from going over and it's been fine ever since. Things that make you go hmmm....

I think this article details the events you saw and highlights why in-rush protection is vital...

https://www.analog.com/media/en/technic ... /an88f.pdf