Hi all,
I have took a closer look on a LM399 shunt reference.
![](https://www.richis-lab.de/images/REF01/00_01.jpg)
Actually it´s a HP-part...
You can find the whole story here:
https://www.richis-lab.de/REF02.htm(german)
![](https://www.richis-lab.de/images/REF01/00_06.jpg)
A nice die with big structures!
![Cool 8)](https://www.eevblog.com/forum/Smileys/default/cool.gif)
Reverse engineering is not a big deal:
![](https://www.richis-lab.de/images/REF01/00_14.jpg)
And here is the buried zener:
![](https://www.richis-lab.de/images/REF01/00_09.jpg)
I found a circuit that´s not in the datasheet:
![](https://www.richis-lab.de/images/REF01/00_13.jpg)
It seems they had to do some fancy compensation.
![Tweak :-/O](https://www.eevblog.com/forum/Smileys/default/smiliey_cal.gif)
And here the heater-circuit:
![](https://www.richis-lab.de/images/REF01/00_12.jpg)
I wrote a lot about the circuit but it´s too late to translate all that words to english. Please use the google translator and ask me whatever you want.
![Popcorn :popcorn:](https://www.eevblog.com/forum/Smileys/default/EatingPopcorn.jpg)
BTW:
I also have a PMI REF01:
https://www.richis-lab.de/REF01.htm![](https://www.richis-lab.de/images/REF01/04b.jpg)
Interesting point: The new ones are ADR01 named REF01.
Have fun!
![Popcorn :popcorn:](https://www.eevblog.com/forum/Smileys/default/EatingPopcorn.jpg)
…does anybody want to donate me a (dead) LTZ1000?
![Grin ;D](https://www.eevblog.com/forum/Smileys/default/grin.gif)
Update: Hey, it seem´s that I´ll get one out of the german mikrocontroller.net-Forum!
![Clapping :clap:](https://www.eevblog.com/forum/Smileys/default/clap.gif)