While populating the BOM for a new design which contains noise-senstive areas I found on Digikey that the TT/Welwyn PCF metal film resistor series has been obsoleted. KOA Speer is still available in metal through others but at higher cost.
Are people not using metal film anymore or why is that?
-- Regards, Joerg http://www.analogconsultants.com/
Joerg wrote in news:fj9pf0F7laeU1 @mid.individual.net:
I think it is a monopoly thing. Look at all the fab houses Vishay bought up, and that is almost all one can get now, and they have a good rep. So the other "dompetitors" wither and die.
Yeah, they are almost like Microsoft and Google :-)
Downside is, when you must buy at the company store the company store can set almost any price they want. And that's gone higher.
-- Regards, Joerg http://www.analogconsultants.com/
The Susumus are great.
Digikey shows 240,000 thinfilm parts. Panasonic, Yaego, TE, Vishay, more.
But thin-films are not usually less noisy than thickfilms, unless tempco makes very low frequency noise somehow.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
It has to be metal and then the selection in standard 0805 size shrivels down to soon-to-be-unobtanium TT/Welwyn brand metal film at 10c or less, and high-precision Vishay metal foil at several bucks a pop. Precision isn't needed.
Mouser and others offer other brands but at significantly higher cost which begins to matter if you need dozens per board.
-- Regards, Joerg http://www.analogconsultants.com/
Have you checked TTI? I have not looked at the mf parts but I've gotten good prices from them on other parts.
The crappy side is they limit your search until you sign up for an account.
-- Chisolm Republic of Texas
Am 12.04.2018 um 21:49 schrieb John Larkin:
I also use Susumu by default. I was never ever disappointed.
My most important customer uses Beyschlag and would not switch. But these do not have the values printed on them. That's ok for their automated assembly, but for my development I want to read what it really is without using the DVM.
Thickfilm / Cermet can produce a lot of noise when there is a DC voltage across them. Worse than carbon composition. Thick film is banned here. Only for 100 Meg or so, there it gets difficult.
Yesterday, I did restock all the np0 capacitors from 1p to 470n. That was a lot of work to look them up and find the best. :-)
regards, Gerhard
Not sure about those. I use a lot of Susumu. I was going over someone elses design, and was going ask why they used spendy 0.1% metal films in through hole. But checked the price before opening mouth, and found that they are reasonable now. (Couldn't find them at mouser... these YR1B1K0CC. from TE)
Only problem is, Susumu is usually only available up to 100ohms in metal and I need more.
Beyschlag is a company I always liked while living in Germany. Then they also got swallowed by Vishay. I never used their round SMT resistors though (Mini-MELF?), they rolled around too much.
I found it only matters in circuits where you really have to hear the grass grow, and only the first stage.
I am gradually retiring so I probably won't have to do that again. Instead, I am stocking up on hops :-)
-- Regards, Joerg http://www.analogconsultants.com/
Their search engine really is the pits. Don't they own Mouser? Mouser is where I found the KOA Speer series available but at higher prices than Welwyn used to be.
-- Regards, Joerg http://www.analogconsultants.com/
What I was told is Mouser is completely seperate from TTI, they don't share stock at all.
Cheers
Am 12.04.2018 um 22:37 schrieb Joerg:
No, I have the whole spectrum here in 0603. From sub-Ohm to > 1Meg.
0603 is the sweet spot for me, they fit the grid given by SO-8 and are in no way hairy to solder by hand. OK, I can do vapor phase here if it is really necessary. Extreme values may be 0805.The solder chicks of a customer of mine boasted that they could solder everything. I gave them my Murata 01005 starter kit. They were horrified after I insisted that the bags were NOT empty. :-)
They also have 0603-like stuff. The MELFs are excellent if you have high peak power or need little C to GND.
Milfs can also be excellent. Ouch. :-)
The CEO of my customer once used Beyschlags for a satellite that flew a great mission. Ordinary parts for TV production, not special thingies in individual glass tubes that have been tested close to destruction. He used to argue that they were used in such quantities, that nothing would work that came from an assembly line if they were not perfect. It seems, he was right.
Nevertheless, we payed more than ?100K for the 100n decoupling caps of our last payload. Abt. 2 shoeboxes in size, and lots of metal for cooling. That were no TV set parts.
We have a lot of precision circuits and it does not pay to have the inventory twice for really good and only ordinarily good.
0.5% thin film as a standard is cheap enough. 1/f with thick film is really ugly.I returned this week from Venice & Salzburg and bought a 6pack of Josephi dark beer in bottles somewhere in Bavaria. I should have bought a lot more. :-(
And that while my fave drug is wine.
regards, Gerhard
We only use thinfilms at 0.1% or less. Some of the Yeago and Stackpole and Panasonic 0.1% 25 PPM parts are around 5 cents by the reel.
The Susumus run 7 to 32 cents, depending on tolerance and tempco. The ones that I tested were below 10 PPM tempco, hard to measure.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
We stock Susumu 0603 and 1206 parts up to 499K.
We're paying 7 cents for RG2012P-4993-B-T5 in moderate quantities.
-- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
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I assumed he meant less than 100 ohm's. Which I think is right. I know I had to buy 10 ohms from someone else.
George H.
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Gerhard Hoffmann wrote in news: snipped-for-privacy@mid.individual.net:
You will not see markings on 0402 and smaller form factor. If you are building larger stuff, they are large enough to put a meter on if you were dumb enough to dispense them haphazardly knowing they were unmarked.
As far as development goes, your proto builder should be keeping track of every component until the circuit is fully characterized
I needed s bunch of 0.5 watt resistors, but found few if any old-fashioned carbon ones at Mouser that were not more expensive than metal film. Huh?
588-OF122JE vs 660-MOS1/2CT52R122J-- A host is a host from coast to snipped-for-privacy@nrk.com & no one will talk to a host that's close.......................... Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433
If it's carbon composite, it has a few special properties. We buy them because the leads are non-magnetic. I think they can also handle higher pulse power.
George H.
For example:
<31 values, 0805, 0R0011 - 10R
currently no stock for the kit, but I got one, so it must exist. I use a lot of 0R5 0805 in the feedback of my low noise amplifiers.
Cheers, Gerhard
OK fair enough. I guess I was looking for 0.1%, of which I can't find any below 47 ohms... (at least at Digikey)
George H.
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