Maybe someone can help me out with this. I'm looking at the data sheet for the STM32L412xx trying to find details on the mapping of the input voltage range to the 12 bit code produced. It might appear that the Vref+ and Vre f- pins define the exact range, but it seems unusual that it could be equal to the power rails. With Vref+ = 3.3V and Vref- = 0 volts does 0V on the input produce a code of 0 and 3.3 volts on the input produce a code of0xFFF and 1.65 volts produce 0x3FF?
Then there are the input circuits. Table 75 says Rain is 50 kohm max. The n table 76 lists Rain max of various values from 100 ohms up. So do fast c onversions really require such low output impedances from the driving circu its? Table 76 has a column without units indicated, Sampling Cycle @80 MHz . Any idea what that is?
Lastly there is mention of an internal op amp. Is there any way to insert this between the input mux and the ADC so that every input won't need a dri ver if we are sampling fast?
I'm thinking there must be a document somewhere that explains the ADC in mo re detail?