Ceramic Capacitor Resources

[T3sl4co1l]

From the esteemed Phil Hobbs on sci.electronics.design:


Hi, All,

Given all the churn in the parts business at the moment, I've been
spending an unconscionable amount of time finding suitable replacements
for out-of-stock parts.  High value ceramic caps are the worst.

Most makers have websites where you can look at the C(V) curves:

AVX: https://spicat.avx.com (This one is super clunky--every time you
select something it displays a throbber for 5-10 seconds.  It does give
you soakage models though, which is nice if they're vaguely accurate.)

Cornell Dubilier has a lifetime/temperature calculator,
http://www.cde.com/technical-support/life-temperature-calculators

Kemet Ksim: http://ksim.kemet.com (about the best)

Kyocera:
https://global.kyocera.com/cgi-bin/electro/cap_download/cdas.cgi?LANG=EN

Murata SimSurfing (Honourable mention):
http://ds.murata.co.jp/simsurfing/mlcc.html?lcid=en-us

Panasonic has downloadable selection tools that don't run under WINE, so
I don't know if they're any good:
https://industrial.panasonic.com/ww/design-support/ds-tools

Taiyo Yuden TY-Compas (Honourable mention):
http://ds.yuden.co.jp/TYCOMPAS/or/searcherMain.do

TDK: https://product.tdk.com/info/en/index.html

Yageo: http://www.yageo.com/portal/product/product.jsp

Samsung has some good datasheets that you can get to from e.g. Digikey's
product page, but a lot of their products are the pits, e.g. this one,
whose capacitance falls off by over 90% at rated voltage:

http://www.samsungsem.com/kr/front/downloadcms.do?path=/kr/support/product-search/mlcc/__icsFiles/afieldfile/2014/11/05&fileName=C_CL31A106KBHNNNE.pdf

Others don't seem to, e.g. Johanson, Vishay, and most of the smaller
Chinese outfits.

Sure would be nice if everybody had decent datasheets like Samsung's
good ones.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

[IDEngineer]

Given all the churn in the parts business at the moment, I've been
spending an unconscionable amount of time finding suitable replacements
for out-of-stock parts.

Been doing exactly the same here. Definitely not the most fun part of the discipline. 

[T3sl4co1l]

Given all the churn in the parts business at the moment, I've been
spending an unconscionable amount of time finding suitable replacements
for out-of-stock parts.

Been doing exactly the same here. Definitely not the most fun part of the discipline. 

I know some guys in VAVE (Value Engineering, basically proposing cheaper alts to the assembly customer) that are basically pulling their hair out the last few months.

Tim

[Conrad Hoffman]

Good resources because, IMHO, you have to be so careful selecting these to begin with, much less substituting them.

[IDEngineer]

Indeed... I suspect I spend more time on caps than any other passives - and probably more than some active parts too. And their performance varies SO MUCH , even within the same manufacturer's lineup, despite the materials and even the basic construction being (apparently) the same.

Many manufacturers only list the most basic specs on their "spec" sheets. I dismiss those immediately, since you literally don't know what you're buying.

[schmitt trigger]

And...with the worldwide passive shortage, things will become more hectic.

Not a week comes by without some materials purchasing agent coming to me asking for a sub, as the approved part may now have a lead time approaching or even exceeding a full year.

[Hydron]

Lately it's been a game of finding substitutes for the substitutes

And yep, mostly MLCC caps here too, though thankfully most of ours are far from critical. Have also had issues with JST connectors though (not ones with chinese clones available either), and am on a barely-adequate (far from a true equivalent to the original) third-choice mosfet in one case. Am crossing my fingers that we don't suddenly end up pulling major overtime hours to design out a bunch of unavailable stuff if a big order comes in.

[JanJansen]

And...with the worldwide passive shortage, things will become more hectic.

Why is this shortage ?
Is it because digital is taking over, or a raw material shortage ?
I did notice prices for WIMAs are higher.

[IDEngineer]

Why is this shortage ? Is it because digital is taking over, or a raw material shortage ?

Digital is a big consumer of MLCC's for supply bypassing. This isn't "just" an analog problem.

Word on the street is that MLCC's are such commodity products that nobody makes any money on them anywhere in the supply chain. So their manufacturers started retooling to make other, more profitable things. Meanwhile electronic consumption has been increasing. That's a classic reduced supply/increased demand situation, leading to shortages and higher prices.

It's not clear how this will get resolved. The manufacturers already know/believe MLCC's are nearly profitless products, so there's little motivation for them to go BACK to making them just to get caught in another price war. Sure, they'd make money in the short term but economic history has a habit of repeating itself.

[Rutger]

I am not sure about a shortage, but I would try out lcsc.com for hobbyist to buy inexpensive caps and other goodies, they are associated with jlcpcb.com (I really like there PCB service, so far the cheapest, best and fastest).
Delivery is reasonably fast ~ about 2 weeks to the USA, but you can't beat there prices.

https://lcsc.com/products/Capacitors_312.html

I am not associated with them in anyway...