SMD Electrolytic - Chamfer

Started by Unlikekurt, July 23, 2019, 07:21:58 PM

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Unlikekurt

Hello.

Does anyone know if there is a standard convention for the chamfer on SMD Electrolytic Capacitors?
I've yet to come across the chamfer dimensioned on any datasheets and would like to add to my silkscreen layer (no, I don't have any on-hand to measure - they'll come once the design is completed).

Thanks!

Rob Strand

#1
I'm not aware of any standard.

width of narrow edge = 0.6 * width of outer edge

You will find it varies across PCB libraries. 
(0.618 would be the most beautiful  ;D.)


Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

Unlikekurt

Thanks Rob,
That's quite close to what I was coming up with.  I'd found 135deg to be a common angle, but couldn't find a sure correlation between location of angle on the side.
Where'd you cull this info from?

Rob Strand

QuoteThanks Rob,
That's quite close to what I was coming up with.  I'd found 135deg to be a common angle, but couldn't find a sure correlation between location of angle on the side.
Where'd you cull this info from?
Yes the angle is always 45 deg/135deg.

It's from many sources.   The most reliable source being real parts and 3D models.  I've found those to be in good agreement.

PCB libraries are all over the place (some use 0.5 in that formula which chops off a lot!).   The dimensioned pics in the datasheets often have smaller chamfers than the real part.   Some of those pics are just generic pics with dimensions whereas others are from the manufactures CAD models.  The problem is you don't know which one it is.
Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.

j_flanders

Quote from: Rob Strand on July 23, 2019, 08:16:18 PM

You will find it varies across PCB libraries. 
(0.618 would be the most beautiful  ;D.)
Yeah, that'd be golden...

Rob Strand

Send:     . .- .-. - .... / - --- / --. --- .-. -
According to the water analogy of electricity, transistor leakage is caused by holes.