Ceramic Capacitor Resources - Page 1
Forum section: electronics / projects

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 25, 2018, 05:23:51 pm
content: From the esteemed Phil Hobbs on sci.electronics.design:Hi, All,Given all the churn in the parts business at the moment, I've beenspending an unconscionable amount of time finding suitable replacementsfor 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 youselect something it displays a throbber for 5-10 seconds. It does giveyou 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-calculatorsKemet Ksim:http://ksim.kemet.com(about the best)Kyocera:https://global.kyocera.com/cgi-bin/electro/cap_download/cdas.cgi?LANG=ENMurata SimSurfing (Honourable mention):http://ds.murata.co.jp/simsurfing/mlcc.html?lcid=en-usPanasonic has downloadable selection tools that don't run under WINE, soI don't know if they're any good:https://industrial.panasonic.com/ww/design-support/ds-toolsTaiyo Yuden TY-Compas (Honourable mention):http://ds.yuden.co.jp/TYCOMPAS/or/searcherMain.doTDK:https://product.tdk.com/info/en/index.htmlYageo:http://www.yageo.com/portal/product/product.jspSamsung has some good datasheets that you can get to from e.g. Digikey'sproduct 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.pdfOthers don't seem to, e.g. Johanson, Vishay, and most of the smallerChinese outfits.Sure would be nice if everybody had decent datasheets like Samsung'sgood ones.CheersPhil Hobbs--Dr Philip C D HobbsPrincipal ConsultantElectroOptical Innovations LLC / Hobbs ElectroOpticsOptics, Electro-optics, Photonics, Analog ElectronicsBriarcliff Manor NY 10510http://electrooptical.nethttp://hobbs-eo.com

author: IDEngineer
author_rank: Super Contributor
timestamp: July 25, 2018, 06:00:18 pm
content: Quote from: T3sl4co1l on July 25, 2018, 05:23:51 pmBeen doing exactly the same here. Definitely not the most fun part of the discipline.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 25, 2018, 06:20:38 pm
content: Quote from: IDEngineer on July 25, 2018, 06:00:18 pmI 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

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: July 25, 2018, 06:23:35 pm
content: Good resources because, IMHO, you have to be so careful selecting these to begin with, much less substituting them.

author: IDEngineer
author_rank: Super Contributor
timestamp: July 25, 2018, 06:27:41 pm
content: 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.

author: schmitt trigger
author_rank: Super Contributor
timestamp: July 25, 2018, 06:56:17 pm
content: 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.

author: Hydron
author_rank: Super Contributor
timestamp: July 25, 2018, 08:23:00 pm
content: Lately it's been a game of finding substitutes for the substitutesAnd 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.

author: JanJansen
author_rank: Frequent Contributor
timestamp: July 26, 2018, 02:21:18 pm
content: Quote from: schmitt trigger on July 25, 2018, 06:56:17 pmWhy is this shortage ?Is it because digital is taking over, or a raw material shortage ?I did notice prices for WIMAs are higher.

author: IDEngineer
author_rank: Super Contributor
timestamp: July 26, 2018, 03:43:32 pm
content: Quote from: JanJansen on July 26, 2018, 02:21:18 pmDigital 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.

author: Rutger
author_rank: Regular Contributor
timestamp: August 16, 2018, 07:35:17 pm
content: 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.htmlI am not associated with them in anyway...