I do component-level repair of tablet mainboards, and I have seen this puzzling situation on two different models of Samsung tablet mainboards so far (SM-T210, SM-T818A). There are ceramic chip capacitors on the PCB that are clearly connected to the ground plane on both ends. Resistance checks...
@PlasmaHH I found that adding the cap gives -10dB of rejection on the other side of the cap (see the answer) with a spice sim, could be useful for some unknown EMI reason
@laptop2d I've noticed that the cap in your simulation is only 0.1uF . The cap in the photo seems bigger than that. It may be 10uF 6.3V (there's little voltage across it) in a 0805 package.
@Marla Sorry for not entertaining you. I have been spending the last few days trying to find a few capacitors that are $0.005 cheaper than the ones we have been using and similar meaningful contributions to the fate of mankind.
(probably dropped a 0 in that capacitor price difference)
I buy some 10uf's in an 0603 but they are more pricey, but maybe that doesn't matter for samsung, I was doing some quick guestimation I'm proabably a little off but it give you an idea of whats going on in the frequency space if the purpose of the cap does anything there
I'm sure some of my parasitics are off also, but I'd imagine that would only shift the pole left or right some
I've seen boards where the ends of SMT caps literally fall off. Part is bad but looks fine on board, until it is desoldered and the end falls off. I was REALLY hoping that junk caps wouldn't make it to the SMT world...
if you have a software system project and you want a list of all the software you use to build it, does that list have some kind of common documentation name for it?
I do component-level repair of tablet mainboards, and I have seen this puzzling situation on two different models of Samsung tablet mainboards so far (SM-T210, SM-T818A). There are ceramic chip capacitors on the PCB that are clearly connected to the ground plane on both ends. Resistance checks...
