Author Topic: LM199/399 is discontinued. EDIT: False alarm.. Apologies.. It was late...  (Read 6943 times)

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Online 2N3055

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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?
« Last Edit: March 19, 2017, 10:03:07 am by 2N3055 »
 

Offline Cerebus

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #1 on: March 17, 2017, 10:49:36 am »
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.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline pitagoras

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #2 on: March 17, 2017, 11:00:23 am »
You can buy LM399 at

http://www.linear.com/purchase/LM399

However in TI page it says OBSOLETE

http://www.ti.com/product/LM399

We can only expect prices to rise :)
 

Offline fmaimon

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #3 on: March 17, 2017, 11:01:34 am »
TI discontinued the LM399 for some years now... Linear still makes them and I don't remember a big price increase...
 

Online Edwin G. Pettis

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #4 on: March 17, 2017, 03:31:13 pm »
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.
 
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Offline ManateeMafia

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #5 on: March 17, 2017, 04:55:20 pm »
I suspect an early April fools prank is being played out on someone. >:D
 
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Online 2N3055

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #6 on: March 17, 2017, 07:47:38 pm »
I suspect an early April fools prank is being played out on someone. >:D

Well joke is on me then...

I read this http://electronicdesign.com/analog/what-s-all-ltz1000-stuff-anyway

I 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..  :palm:    In my defense, it was late..  :=\
« Last Edit: March 17, 2017, 08:04:15 pm by 2N3055 »
 

Offline RobK_NL

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Tell us what problem you want to solve, not what solution you're having problems with
 

Online NANDBlog

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #8 on: March 18, 2017, 01:30:43 am »
I suspect an early April fools prank is being played out on someone. >:D

Well joke is on me then...

I read this http://electronicdesign.com/analog/what-s-all-ltz1000-stuff-anyway

I 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..  :palm:    In my defense, it was late..  :=\
At 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.
 
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Online Richard Crowley

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #9 on: March 18, 2017, 01:44:40 am »
Hopefully, AD will have the brains to keep their hands off of the LT operation and not ruin a very good thing.
Sometimes 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.
 
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Online Edwin G. Pettis

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #10 on: March 19, 2017, 02:45:43 am »
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.
 
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Online 2N3055

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #11 on: March 19, 2017, 03:20:11 am »
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.

Thank 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.
 

Offline doktor pyta

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #12 on: March 19, 2017, 03:38:48 am »
« Last Edit: April 22, 2017, 06:32:40 pm by doktor pyta »
 
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Online TiN

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #13 on: March 19, 2017, 05:39:05 am »
LTZ1000 was always single source AFAIK, designed by LT, and sold only by LT :)

LM199 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.
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Offline VK5RC

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #14 on: March 19, 2017, 07:21:43 am »
@2n3055, is it worth altering/adding addendum to  the title of the post?
Robert.
Whoah! Watch where that landed we might need it later.
 
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Online 2N3055

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #15 on: March 19, 2017, 10:01:46 am »
@2n3055, is it worth altering/adding addendum to  the title of the post?
Robert.

Indeed! You're right!!
 


Offline Alex Nikitin

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #17 on: April 01, 2017, 10:25:07 pm »
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:IYoAAOSwu1VW2jIb

miilitary grade  LM199:
http://www.ebay.com/itm/2PCS-LM199AH-883-Encapsulation-Precision-Reference-/272159387538?hash=item3f5df6af92:g:210AAOSwdGFYuS19

How reliable are these sources? Is there any chance these are fakes?

I'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.

Cheers

Alex
 

Offline Cerebus

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #18 on: April 02, 2017, 12:48:57 am »
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:IYoAAOSwu1VW2jIb

miilitary grade  LM199:
http://www.ebay.com/itm/2PCS-LM199AH-883-Encapsulation-Precision-Reference-/272159387538?hash=item3f5df6af92:g:210AAOSwdGFYuS19

How reliable are these sources? Is there any chance these are fakes?

I'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.

Cheers

Alex

You 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.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 

Offline Alex Nikitin

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Re: LM199/399 is discontinued. For real. What is replacement?
« Reply #19 on: April 02, 2017, 01:31:10 am »
Which variant did you plump for? Keep us updated.

LM199A-883. The plastic enclosure looks bad and the leads are uneven, "tapered" and badly cut. Nothing like the real thing.

Cheers

Alex
 

Offline Alex Nikitin

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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.

Cheers

Alex
« Last Edit: April 02, 2017, 08:11:09 am by Alex Nikitin »
 
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Online SeanB

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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.
 

Offline doktor pyta

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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.
« Last Edit: April 23, 2017, 05:56:17 pm by doktor pyta »
 
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Offline Cerebus

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Those 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.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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