A vast majority of this die looks like low density analog to me
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif)
I think they may have a complementary process here given the additional diffusions surrounding some transistors, presumably PNPs. A wild guess as to what is what:
![](https://www.eevblog.com/forum/metrology/more-voltage-references-die-pictures/?action=dlattach;attach=1053702;image)
As can be deduced, I'm not exactly sure what WAT and WTF might be. Perhaps larger BJTs, or maybe MOS? Who knows, MAX6250 datasheet says it's fabbed on a CMOS process, maybe this one is BiCMOS. But MAX6350 datasheet also says 435 transistors and I have no idea where they are.
I agree with Noopy that the left side is probably the output stage. This means the bondig pads are, top-bottom and left-right:
output stage ground, precision ground, noise reduce, input voltage, do not connect
trim, output voltage, probably output sense, dnc, dnc
It seems to make sense. Ground, input and output are quite fat. Noise reduce appears to cross under a Vin trace and go to some circuitry in the top right corner. Trim is another thin trace which goes somewhere to the right.
edit
For instance, the pair of structures below the P in NPN appears to be a simple current mirror, with the top tranny being the input (B-C shorted). The one I labeled PNP also seems B-C shorted, but an identical transistor on the right is not. I'm pretty sure that the "zeners" are indeed zeners because they look similar to other zeners we have seen and what else could those things be with apparently only two terminals?