LM199/399 is discontinued. EDIT: False alarm.. Apologies.. It was late... - Page 1
Forum section: electronics / general

author: 2N3055
author_rank: Super Contributor
timestamp: March 16, 2017, 11:41:03 pm
content: EDIT: False alarm.. Apologies.. It was late...Hello all!At first I was sceptical but it seems that LM199/399 is really discontinued.What will happen with all those 6.5 digit DMM that use it as reference. I know they have stock for some time but new development ?Will it be manufactured for large T&M manufacturers but not for public sales?There is no alternative to it, non heated references are close but not really in it's class (good for 5.5 digit maybe), and LTZ1000 is 10 time more expensive, even more with support circuitry, and harder to integrate ...It is really shame...What are you thinking?

author: Cerebus
author_rank: Super Contributor
timestamp: March 16, 2017, 11:49:36 pm
content: Why do you think it's discontinued? It's not even marked as 'not recommended for new designs', let alone obsolete on either TI's or Linear's web sites.

author: pitagoras
author_rank: Regular Contributor
timestamp: March 17, 2017, 12:00:23 am
content: You can buy LM399 athttp://www.linear.com/purchase/LM399However in TI page it says OBSOLETEhttp://www.ti.com/product/LM399We can only expect prices to rise

author: fmaimon
author_rank: Unknown
timestamp: March 17, 2017, 12:01:34 am
content: TI discontinued the LM399 for some years now... Linear still makes them and I don't remember a big price increase...

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: March 17, 2017, 04:31:13 am
content: TI never did make a LM399 in any flavor, they acquired the LM399 when they bought up National a few years ago. Linear Tech still makes them and as I recall their specs for the LM399A is slightly better than the old National parts. Hopefully, AD will have the brains to keep their hands off of the LT operation and not ruin a very good thing.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: March 17, 2017, 05:55:20 am
content: I suspect an early April fools prank is being played out on someone.

author: 2N3055
author_rank: Super Contributor
timestamp: March 17, 2017, 08:47:38 am
content: Quote from: ManateeMafia on March 17, 2017, 05:55:20 amWell joke is on me then...I read thishttp://electronicdesign.com/analog/what-s-all-ltz1000-stuff-anywayI went to check and sure enough, Texas Instruments shows it as OBSOLETE...I didn't check Linear site..Farnel is out of stock. RS also, Mouser doesn't have it at all, Arrow has 8 pieces.. TME has 9 pieces at more than 12 USD that is very pricey...BUT, it did got me thinking. It is single source now. And it is obvious that this blatant and deliberate misinformation by the said gentleman was designed to boost sales of LTZ1000.. But article literally stated :"“National/TI obsoleted the LM199, so the LTZ1000 is the only replacement in the industry that I know of."So Linear ( or should I say Analog devices, the new boss) pretends they don't make LM399 and that you should buy LTZ1000 as only replacement...Does this mean that Analog is thinking of discontinuing it too??So sort of a false alarm.. Sorry for that.. But something fishy is going on.....P.S. Thanks to everybody for taking their time to set me straight..In my defense, it was late..

author: RobK_NL
author_rank: Frequent Contributor
timestamp: March 17, 2017, 01:21:39 pm
content: How many do you need?https://www.digikey.nl/products/en/integrated-circuits-ics/pmic-voltage-reference/693?k=lm399

author: tszaboo
author_rank: Super Contributor
timestamp: March 17, 2017, 02:30:43 pm
content: Quote from: 2N3055 on March 17, 2017, 08:47:38 amAt some point as far as I remember, the LM199/399 was obsolete by Linear also. They forgot to mention, that they are making the Pb-free version, and that is why. So no worries.

author: Richard Crowley
author_rank: Super Contributor
timestamp: March 17, 2017, 02:44:40 pm
content: Quote from: Edwin G. Pettis on March 17, 2017, 04:31:13 amSometimes it's not a matter of "keeping their hands off". Sometimes it is a matter of maintaining the production or not. Tools wear out and can't be repaired or replaced. Materials become no longer available, etc. For example all the great audio chips that TI inherited from National which are EOL because they were produced on an old production line which is no longer economical to operate.

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: March 18, 2017, 03:45:43 pm
content: I just checked with Linear Tech, there is no notice of discontinuation, both versions of the LM399AH and LM399H are available, priced at $9.37 and $6.46 each.

author: 2N3055
author_rank: Super Contributor
timestamp: March 18, 2017, 04:20:11 pm
content: Quote from: Edwin G. Pettis on March 18, 2017, 03:45:43 pmThank you so much for taking time and effort to check it with them..I apologize for alarmism, I should have known better that to trust an article without making thorough check.The fact remains , though, that Linear remains single source for both LTZ1000 and LM399... Lets hope Analog won't change too much, or don't hike up prices...Thanks again.Regards, Sinisa.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: March 18, 2017, 04:38:48 pm
content: Hi guys,dry Your tears.I have something nice for You (not my auctions).Space grade LM199:http://www.ebay.com/itm/2PCS-5962-8856101XA-V-Ref-Precision-6-95V-10mA-4-Pin-TO-46-Tray-/272157035290?hash=item3f5dd2cb1a:g:IYoAAOSwu1VW2jIbmiilitary grade LM199:http://www.ebay.com/itm/2PCS-LM199AH-883-Encapsulation-Precision-Reference-/272159387538?hash=item3f5df6af92:g:210AAOSwdGFYuS19You owe me a beerWarning!: read Reply #20 and Reply #22

author: TiN
author_rank: Super Contributor
timestamp: March 18, 2017, 06:39:05 pm
content: LTZ1000 was always single source AFAIK, designed by LT, and sold only by LTLM199 indeed obsoleted long ago, replaced by commercial grade LM399. Both are same hermetic package. Other than tighter selection/binning for 199 there seem to be no difference.I wouldn't worry much, as these are niche and wanted products, which have no replacement up to date.

author: VK5RC
author_rank: Unknown
timestamp: March 18, 2017, 08:21:43 pm
content: @2n3055, is it worth altering/adding addendum to the title of the post?Robert.

author: 2N3055
author_rank: Super Contributor
timestamp: March 18, 2017, 11:01:46 pm
content: Quote from: VK5RC on March 18, 2017, 08:21:43 pmIndeed! You're right!!

author: exe
author_rank: Unknown
timestamp: March 25, 2017, 11:08:43 am
content: Quote from: doktor pyta on March 18, 2017, 04:38:48 pmHow reliable are these sources? Is there any chance these are fakes?

author: Alex Nikitin
author_rank: Super Contributor
timestamp: April 01, 2017, 11:25:07 am
content: Quote from: exe on March 25, 2017, 11:08:43 amI've received a couple today. From the visuals - fakes. I have no time to do a proper investigation today, but will do tomorrow. Probably will cut one open too.CheersAlex

author: Cerebus
author_rank: Super Contributor
timestamp: April 01, 2017, 01:48:57 pm
content: Quote from: Alex Nikitin on April 01, 2017, 11:25:07 amYou couldn't have timed this better. Earlier this week I managed to stuff 250mA reverse bias @ 15V through the 'zener' side of one of my supply of breadboarding LM399s (off by one hole wire misplacement) depleting my experimental stock to 2. I was wondering about chancing my arm buying some of these as replacements for the curiosity value (never had any LM199s). So I'm quite curious.Which variant did you plump for? Keep us updated.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: April 01, 2017, 02:31:10 pm
content: Quote from: Cerebus on April 01, 2017, 01:48:57 pmLM199A-883. The plastic enclosure looks bad and the leads are uneven, "tapered" and badly cut. Nothing like the real thing.CheersAlex

author: Alex Nikitin
author_rank: Super Contributor
timestamp: April 01, 2017, 10:08:17 pm
content: Here is a quick update and some photos. At least the Zener part behaves as it should, with ~7V voltage drop and less than 1 Ohm dynamic impedance. As the pins are extremely fragile it is almost impossible to test the part properly in a socket. I might solder some thin wires to it for testing. As you may see, the leads are badly mutilated, looks like they were filed with a needle file to remove the tin plating and then gold (?) plated. If the heater also behaves as it should the most likely explanation is re-marking of a (copy?) 399 into a high grade one. I've already had a first-hand experience with Chinese re-marks of this kind, where a perfectly good part was filed/sanded and then re-marked with a different date code, and at the same time ultimately damaged so it can not be used. In any case, this IC is essentially unusable due to damaged pins and unknown origin, so I am initiating a complaint with eBay.Photos show the fake IC side by side with a bona fide LM399 from Linear.CheersAlex

author: SeanB
author_rank: Super Contributor
timestamp: April 02, 2017, 10:08:34 am
content: Looks like they took a recycled part and welded new legs on to it, then plated ( or painted) gold onto them. Chamber looks like it either got cooked in a fire, or is a very cheap moulding made from another part.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: April 22, 2017, 08:30:34 am
content: I confirm what Alex Nikitin wrote.I found it and I'm also a victim...I bought 6 pcs of 5962-8856101XA from ebay user 'crystal830303'.They arrived yesterday.First picture shows what was advertised, second shows what I got, third shows the IC with pants-down.As You said they have poorly reconstructed leads.Info: The seller returned the money without any problems so at least he is honest at this point.

author: Cerebus
author_rank: Super Contributor
timestamp: April 22, 2017, 10:41:35 am
content: Quote from: doktor pyta on April 22, 2017, 08:30:34 amThose look like old park railings, that some council employee has re-painted with gold paint but has been too lazy or stupid to get the rust off first.