Hi, Mel

...

and I do think it's the same for all the manufacturers ...

just have a look to µChip AN 544d ... or the Midrange Manual ... they all show code $3FF for 1023 LSB ... not Vref , which is 1024 x LSB ! ( see § 23.12 )

Would be interesting to verify which input voltage give code 255 for a 2.56v ref ( quite simple !) , ... give code 4095 for a 4.096 v Vref ( less simple ), etc, etc.

don't you think ???

Regards
Alain