Timeline for Protecting USB hub from ESD
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 19, 2019 at 10:22 | comment | added | djvg | @AndroidDev: For what it's worth: Having my curiosity awakened, I just measured the shield-ground resistance on ten "consumer level" usb-hubs in the 5-30 euro price range, from different manufacturers, including icy-box, anker, sitecom, speedlink. None of them had any appreciable resistance from shield to ground (all <0.5 Ohms). Most had upstream-shield, downstream-shield, and board-ground connected, but some had either upstream-shield or downstream-shield unconnected. | |
| Nov 29, 2018 at 5:13 | comment | added | Ale..chenski | @AndroidDev, see also some major background here (ESD and EMI are parts of the same problem), emiguru.com , and this article in particular 7ms.com/enr/online/2010/02/notebook.shtml | |
| Nov 29, 2018 at 4:10 | comment | added | Ale..chenski | @AndroidDev, Section 11.8.3 is from USB 2.0 base specifications, found in any USB.org document source, inside a big ZIP file. usb.org/document-library/… Regarding shielding, "Ask six electrical engineers how to correctly ground and shield a measurement system, and you’ll likely get 12 different answers." edn.com/electronics-news/4381145/… | |
| Nov 29, 2018 at 3:24 | comment | added | You'reAGitForNotUsingGit | Alright, so, two questions 1) Do you have a link for Section 11.8.3? and 2) Can you point me to a source that details more about how the shield should be connected properly to the signal ground instead of just tied together? (I was talking to someone else and they didn't seem to agree that it was a problem) | |
| Nov 26, 2018 at 2:04 | comment | added | Ale..chenski | @AndroidDev, yes, this is bad. | |
| Nov 26, 2018 at 2:03 | comment | added | You'reAGitForNotUsingGit | "The most serious problem is when the cable shield on hub ports (in both directions) is not connected properly to signal ground plane, if it is simply tied together" Ok, so I probed the resistance from the shield to the GND pin, and my meter reported about 0.7 ohms. So that means that they're connected directly, and that's bad, right? | |
| Nov 21, 2018 at 22:55 | history | edited | Ale..chenski | CC BY-SA 4.0 |
added 370 characters in body
|
| Nov 21, 2018 at 14:50 | history | answered | Ale..chenski | CC BY-SA 4.0 |