EEVblog Electronics Community Forum
General => General Technical Chat => Topic started by: TimNJ on March 21, 2018, 02:31:28 pm
-
Hi all,
Been working on a BOM for a new product at work. Looking for caps on Digikey, I've noticed a new (but not unfamiliar) name appear in the manufacturer choices: Samsung. For capacitors in particular, their prices are really, really good. (Usually cheaper than all of the other options by some margin.) I don't know if the highly competitive pricing is correlated to the insane amount of government subsidies that Samsung receives, but that's neither here nor there. It's hard to say "no" to cheaper parts!
That said, anyone have ideas on the quality and reliability of Samsung passives? I assume they know what they are doing.
http://www.samsungsem.com/global/product/index.jsp (http://www.samsungsem.com/global/product/index.jsp)
-
Samsung are a fairly reputable brand nowadays.
My local distributor has recently starting pushing Suntan, a Chinese manufacturer of capacitors and resistors. I've never heard of Suntan before and the name sounds funny, so I avoid them, especially the aluminium electrolytic and tantalum varieties. I'm considering ordering some Suntan 220pF ceramic capacitors, because they don't sell anything else, it's part of a larger order and it's a fairly low risk application: EMI filtering on an line level audio signal.
https://www.rapidonline.com/brands/suntan?ra_source=tier-page?Tier=Capacitors (https://www.rapidonline.com/brands/suntan?ra_source=tier-page?Tier=Capacitors)
-
I've used some Samsung caps, and they don't exactly delight me. Never had any failures, but the ceramic looks somewhat uneven, and the terminals are sometimes not as well finished as with proper makes. I think a quality ceramic cap should be somewhat shiny, or at least entirely smooth; the Samsung ones look like something that broke off of a flower pot into convenient rectangular chunks.
Since I never make anything that's massively cost-sensitive, I tend to buy TDK parts simply because of their parametric search.
-
I find them cheap. You generally get what you pay for unless a manufacturer is undercutting to get into a market.
Their high value MLCC's have a high voltage-coefficient of capacitance, when you find that hidden spec. Their datasheets are terrible.
A few shorted so I no longer spec them, at all.
I use AVX, Murata, TDK, Taiyo Yuden, Johanson for RF.
-
Interesting. There are a few parts on board that definitely can't have poor voltage-capacitance coefficients. May have to revisit some high value parts to see see if I specified a not-so-good Samsung.
Regarding finish, any reason to believe terminal finish is correlated to reliability? Does it really matter?
Thanks!
-
That's been my limited experience with them; poor CV/$ or /size, and the C-V graph isn't always handy, seems like 30-40% of datasheets have it listed, the rest you may or may not be able to find in the catalog or on their website.
Other than that (a common rigmarole for any type 2 dielectric), I don't know of any reliability problems with them.
Tim
-
Here is the Samsung CL series capacitance- DC bias graph. Wow those curves look really good. Better than any other make (X7R) ;)
Notice the graph is kindergarten grade. X-axis stretched and wonky, maybe 5V/div or 0-50V.
Y5V part is unknown voltage.
X7R 16V part perhaps -10% at 1/2 rated voltage.
X7R 50V part perhaps -0% at 1/2 rated voltage.
If you believe these curves, you're gonna have a bad day.
-
Here is the Samsung CL series capacitance- DC bias graph. Wow those curves look really good. Better than any other make (X7R) ;)
Notice the graph is kindergarten grade. X-axis stretched and wonky, maybe 5V/div or 0-50V.
Y5V part is unknown voltage.
X7R 16V part perhaps -10% at 1/2 rated voltage.
X7R 50V part perhaps -0% at 1/2 rated voltage.
If you believe these curves, you're gonna have a bad day.
Yikes who let that graph see daylight. :o Yeah, based on that alone, not too much confidence in the parts. I think I'll just specify TDK, Murata etc. Just prototypes anyway. Our Chinese factory will figure out low cost, local sourcing when the time comes.
Thanks for the input!
-
Its all in the specs. You get what you pay for. Generally they are fine. We have used them in production from their distributor and have had no problems. We generally spec things on the tighter end of the spectrum. Especially ceramic caps, and we only use 1% or better resistors. I would not pass on Samsung parts based solely on name. Only on Spec and performance.