[time-nuts] FE-5680A - Newbie capacitor question

[Dan Kemppainen]

Hi,

Sorry, I had to jump in here. Ceramic capacitors are NOT less likely to 
suffer damage hand soldering. They are very susceptible to damage hand 
soldering. This is especially true if you are using the larger sizes 
(1206 and up).

Placing the tip of a hot soldering iron against the end of ceramic 
capacitor causes very high localized heating and temperature gradients. 
This results high localized stress concentrations, which can result 
internal damage to the capacitor. The result is a shored capacitor 
immediately after soldering, or sometime later during operation.

It's best to read up on the datasheet for the particular cap you are 
buying, but often times they state not to hand solder.

I'd highly recommend using a hot air reflow station, even the cheap $40 
chinese ones. If you can't use hot air, be sure to only touch the solder 
pad with the iron, and not the capacitor directly. Let the solder flow 
the heat to the capacitor through the pad.

All the above said, the smaller sizes 0603 and 0402 don't seem to be 
particularly vulnerable to soldering irons. Higher voltage capacitors 
don't seem to be as vulnerable in the same size. And anything at or 
above 1206 seem to be much more sensitive.

Also, minimize the solder between the cap and pad. Use the bare minimum 
necessary. Using a large 'blob' of solder or large fillet allows the 
board to transfer bending stresses to the cap, causing failure as well.

I do agree, once they're on a board they're much more robust than the 
tants. But care needs to be taken getting them there.

Just my very hard earned two cents! :)

Dan




On 5/2/2020 12:00 PM, time-nuts-request at lists.febo.com wrote:
> 
> If it were me, and assuming it is at the input of  a linear regulator, I
> would put a ceramic multilayer capacitor in its place.
> It will likely be much smaller (requiring a short jumper to match the
> solder pads of the larger tantalum) but a lot more reliable, and you are
> less likely to damage it by hand soldering.