I got out my microscope. Only 640x480, but not bad... I can make out an initials FB
So what might it be?
Excellent pics. I hope I get something worthwhile to show.
Send me PM if you would like to know exact IC they are selling as LTZ.
Why not just tell us all?
I will need the die to use better magnification.
So if someone will send me the IC I will try to identify and of course post what it is or at least hires picture like I did for LTZ1000 from TiN.
Here are photos of one that I got from eBay. It came from a US seller and I paid around $45 for it. The pins are about .45mm in diameter. I measured the resistance of the heater and it's about 240 Ohms.
So what might it be?
The question is: what is cheap and comes in a TO-99 package?
The structures on the left side of the die look like 3 "power stage transistors". right?
The only chip I know with 3 output transistors is a NE555. (best guess).
No its not a genuine NE555, but it might be a CMOS or fake derrivate.
With best regards
Andreas
There is mark FB on Macbeth chip. You ca guess what it is
I didn't know Facebook is fabricating its own silicon circuits.
Thanks plesa. So there's the
FB in the middle and
BF on the top left which my microscope didn't pick up. I must upgrade the firmware to that next model up that you use
I'm guessing they are for lining up the back and front images correctly in manufacture rather than a makers mark.
Although it could be a top secret state of the art quantum processor component from Facebooks data warehouse that Zuckerberg had labelled LTZ1000 to hide it away from industrial espionage. Somehow it ended up on Aliexpress
... or maybe its an op-amp
I recently purchased some LTZ1000's from AliExpress.
Did you get an answer back yet from Aliexpress? What happened?
I swear I wrote a small account of what happened but it seems to have just vanished. Suffice to say I got my refund in full.
Just buy them from LT direct shop
Just buy them from LT direct shop
That would be by far the best. I've given up on LTZ for now and got a pair of LM399A's and associated opamps direct from LT to play with (free samples
)
Just buy them from LT direct shop
To add my 2cents: simply buy the LTZ1000 CH, NOT the A version.
That's 35$ from LT, and it's better for building a REAL precision reference.
I'm still wondering, why so many people still copy the faults of HP!
I prefer copying superior Pickerings (7001), Datron 4901, Datron 1281 references, all using non-A @ 45°C or slightly above!
Frank
Can you not also run the 'A' at 45 degrees? Isn't that what HP3458A "Option 002" is?
Option 002 is just selected reference with lower drift, still @high temperature.
Some people use battery to run LTZ, so that would be better for A-version. Also after all, both versions would be not that far off after aging/conditioning completed.
Can you not also run the 'A' at 45 degrees?
Nope, the thermal isolation automatically increases necessary oven temperature by 10°C.
With 35°C max room temperature, plus 5°C regulation margin plus 10°C adder for A version, that's not feasible.
The "A" version better runs at 55°C, non-A can run at 45°C.
Environmental temperature has to be limited, and monitored, in either case.
As TiN already wrote, 45°C or 55°C, and even 65°C give nearly the similar stability, after some time.
45°C oven temperature is a non-brainer concerning drift, anyhow.
Frank
Can you not also run the 'A' at 45 degrees?
Nope, the thermal isolation automatically increases necessary oven temperature by 10°C.
With 35°C max room temperature, plus 5°C regulation margin plus 10°C adder for A version, that's not feasible.
The "A" version better runs at 55°C, non-A can run at 45°C.
Environmental temperature has to be limited, and monitored, in either case.
As TiN already wrote, 45°C or 55°C, and even 65°C give nearly the similar stability, after some time.
45°C oven temperature is a non-brainer concerning drift, anyhow.
Frank
I've read the above statement several times now in this forum, but from the data sheet of the the LTZ I don't see any evidence that the A version cannot be run at 45°C or 55°C. From what I understood the chip is just better isolated from the (bottom of the) case so that the same temperature can be achieved with lower heater power.
On page 3 of the data sheet "temperature rise vs heater power" it is shown that the A version just needs 0.1 W for 45°C while the non-A needs around 0.25W.
Do I miss something here?
J.C.
Hi all,
For reference........photo of an LTZ1000 I got from Digikey.
Also pictured some LM399's I got from Ebay..........hmmmmm!
Ian.
Those LM399's look dodgy, my samples direct from LT have PHILIPPINES E14237 stamped on the sides. Yours don't have anything!
Some photo's of quite old LTZ1000 's which are not fakes and have all silver pins (never been soldered, only plugged into a socket for burn in), for your further pictorial reference (Sorry for the pun , I will whip myself later!)
Work had purchased a 'Decent' quantity for the purpose of selecting after the aging was completed.
The measured heater resistance on 2 units from the pic was 276 ohms and the other 279 ohms, pins 1 and 2.
Those LM399's look dodgy, my samples direct from LT have PHILIPPINES E14237 stamped on the sides. Yours don't have anything!
Interestingly I also have a number of old LM399 refs and those have no text on the side either, and look the same as the pic from IanJ. ie National semi branded.
Perhaps his are old stock too !.
Some photo's of quite old LTZ1000 's which are not fakes and have all silver pins (never been soldered, only plugged into a socket for burn in), for your further pictorial reference (Sorry for the pun , I will whip myself later!)
Work had purchased a 'Decent' quantity for the purpose of selecting after the aging was completed.
The measured heater resistance on 2 units from the pic was 276 ohms and the other 279 ohms, pins 1 and 2.
Maybe it's only the 'A's that have the gold pins? I mean they need something to justify the extra cost!
Some photo's of quite old LTZ1000 's which are not fakes and have all silver pins (never been soldered, only plugged into a socket for burn in), for your further pictorial reference (Sorry for the pun , I will whip myself later!)
Work had purchased a 'Decent' quantity for the purpose of selecting after the aging was completed.
The measured heater resistance on 2 units from the pic was 276 ohms and the other 279 ohms, pins 1 and 2.
Maybe it's only the 'A's that have the gold pins? I mean they need something to justify the extra cost!
Both have gold plated pins now ( I have 4 LTZ1000 manufactured 1443).
Wow, 6 centuries ago.
That's some serious aging! Designed by a druid, manufactured by blacksmiths hammer and anvil, leads turned to gold by alchemy, then ovenised over the centuries in the blacksmiths forge and passed from father to son...
Link to the CERN ultra precision 10mA current reference (based on LTZ1000A):
http://cds.cern.ch/record/643294/files/cer-002399331.pdf
Thanks for the link! Good to know CERN has a couple of projects as well as messing around with the LHC and KiCAD development