REF01 - different generations - die pictures

[Noopy]

Hi all!

I hope it´s ok to start a new topic for the REF01. I found no existing topic.

Up to now I have decapped four REF01-generations and would like to share them with you.


The first generation die was packaged 1976:




The second generation was developed 1977:





The third generation is missing. Probably it´s only one year in which it could have been produced. "My" generation 2 package dates back to 1986 and generation 4 was designed 1987. But there must be a generation 3 because the designs have names with a revision coding: 1800Z, 1800Y, 1800W => The X is missing. Perhaps generation 3 was buggy.


The fourth generation was developed 1987:



There is a die picture in a datasheet that probably shows the generation X. With an overlay you can spot the small changes:




The fifth generation is actually a ADR01 as the REF01 moved to Analog:



Sorry, bad picture...


From 1 to 2 PMI did only small geometry changes at the output and at one double transistor.
From 2 to 3 there were added more resistors and fusable links to adjust the Output voltage and the temperature drift. The startup circuit was changed. The die got bigger. Two spare transistors were added, perhaps for the startup circuit. (Actually I have no generation 3 but with the picture out of the datasheet it seems it got all the changes you can see in generation 4.)
From 3 to 4 the spare transistors were covered by the output metal layer.
From 4 to 5 Analog wanted to earn more money and canceled the REF01 by putting ADR01 in the packages.


Overview over all:
https://www.richis-lab.de/REF00.htm


Greetings,

Richard