Electronics > Projects, Designs, and Technical Stuff
Ceramic capacitor cracking
(1/1)
zenerbjt:
Hi,
This is the best thing ive read on ceramic cap cracking
https://www.youtube.com/watch?v=QgKY5QWehME&feature=youtu.be
...however, at 17:47 onwards, it seems to suggest that a lot of flexion can be tolerated....up to "4mm".
I work with a PCB which is approx 15cm by 25cm and it has multiple 47uF, 16V, X6S, 1210 caps on it. They are placed in both directions, (so one of the directions is wrong).
Being high value, the problem is worse, but i need the best ceramic cap crack video/tutorial out there to convince them that a change to Flexiterm/Thru-hole etc is worth while...they dont want to re-spin the PCB.
Do you know of the best tutorial/video on this subject.?
temperance:
Are those capacitors on the edge of the board? Ceramic caps usually crack when the board are being de-penalized and the capacitors are perpendicular to the board edge.
If this is related to the question about connectors and connecting batteries, then inrush current is the problem.
zenerbjt:
Thanks, but no the ceramic MLCCs are away from the edge, but according to the video in the top post.....depanelization is just one factor, not the main factor. Its not clear though, how much board bending causes cracking.
..Thus if you bring this up in a company, and request changes, people just shrug it off and ignore it.
TheMG:
Just design the enclosure/chassis to be rigid enough and properly supports the PCB to avoid bending/flexing. Good support around areas of the PCB with any connectors which will be inserted/removed more frequently, etc
Doctorandus_P:
Reminds me of a video where Davey Jones lets out the magic smoke of a 50V 20A power supply.
In a followup video it's explained that ta ceramic cap just under the screw terminals was the culprit. You need to exert some force to the screw connectors for the 20A cable, which flexes the PCB and damages the cap.
The simplest solution is to not flex the PCB (too much) during handling & mounting.
Ther are special ceramic caps which have a little bit of flexibility built in, but you probably have to pay extra for that. Dave also did a video on those.
Navigation
[0] Message Index
Go to full version