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Pin Protection Advice


DRC of 8 --> line of 8 passes, line of 7 fails.


Hmmm… I’m at a Super Bowl party. Will play more when I get home.


you should have just left - 49ers never had a hope, even with the comeback. Yes, even in AU we see the game… although a party at lunch time on a Monday wouldn’t necessarily be looked at positively :wink:


Yea… I wasn’t interested in either team. My wife is in charge of my social calender, though… If it weren’t for her I’d probably never leave this seat. :slight_smile:

Ok. I’ve found the source of the problem. It’s coming from a custom part I made. For some reason it seems to be enforcing it’s own rule to wires attached to it. I’ve yet to figure out where to adjust this. If you want to try it, the device is called “VESD05A8A-HNH-GS088-UFDFN” and is located at:


Eagle dies on me when I go to look at the details in the footprint. Time to reinstall I think (and I really wish they’d make it easier to separate data from the app - create directories in userdata and add them to the default libraries location)


Thanks for trying. Good luck with your reinstall.


@ ianlee74 - Just tested your part fine with 6mil traces - dru is happy in 6.1…


Thanks, Justin. Looks like I’ll be trying to re-install Eagle also.


Did you check?

Edit->Net classes…


I’ll look at that tonight. I don’t think I’ve ever looked in there. What specifically would I be looking for that could cause this?


Any larger value that is in the Width edit box of the “Net classes” dialog overrides DRC rule

For example you have minimum width in DRC Size tab set to 6mil, but if the Net class width is set to 10mil - DRC will fail for anything that is less then 10.


Ah… Interesting. Definitely sounds like a likely candidate.


I modified the post: any larger value. Same applies for minimum drill.


You are the [superhuman] man! The “default” setting in there was 10mil. Changing that fixed it. I know I’ve never changed that. It must have came that way as a default. So, I’m curious why none of you have this. What does your “Net classes” page look like?


Glad it helped.

I think it is project dependent. I have just started from scratch and it is set to 0. I have opened few existing projects that come with Eagle and the values are different for each project.


Interesting. I just started a new project and there is only one row and everything is set to 0. My other project has three rows of values - “default”, “power”, & “12v”. “default” has real values and the other two are zeros. I tried adding some parts to the new project to see if these values were coming in from a library but nothing I can do is populating those values. I’m going to have to do some studying and find out more about this settings page.


or live in ignorance like the rest of us :wink:

c’mon in, the water’s fine!


I found this topic very interesting. I am playing with one wire devices and I built a pcb with several DS2408 and a 5V buck boost power supply. in fact it seems that each time I disconnect the power supply, the EMX pins connected to the one wire network are burning out (already 5 pins burned on 2 different EMX !!!). Therefore I need to protect EMX IOs. Do you have any advice?


After Igmoe’s recommendation, I have integrated this IC into my design. It sounds like it should work for you also. Fingers crossed.

EDIT: I just realized I pasted in the wrong part. If you’re only concerned with protecting 3V3 pins then the above is actually a better choice but since my module is also planned for use with arduino (5V pins) then I actually went with the below. I went to order the parts and realized the link I had copied into my notes was the wrong one. Sorry about that.


An other IO have burn out on the third prototype board. I have protection on the one wire busmade of a DS9503, a shottky diode (BAS 40) to avoid backward current and PolyFuse MF-PSMF010X as adviced by Dallas expert. The network is supplied at 4.8V and pull up with a 2.5kOhm resistor. This thing makes me nut and I don’t really know where to start to solve this problem. Should I decrease the voltage bellow 3.3V?