Posted on February 14, 2009 at 08:37Hi everybody,
Each time I build a new schematic, I place components between my ST7LITE1XB or STLITEFOXK1 anolog inputs and the output from the divider supplied by the source I'm measuring. I do that to avoid voltage (between 0 and 5Vmaxi)on the analog inputs when the VDD pin is not supplied (for example I can get battery voltage on ANX and the ST7 is not supplied because the AC adaptor is not plugged! So when my ST7 is supplied, the first thing my software is doing is to drive the transistors that connects the sources I want to measure to the analog inputs.
In all the application notes from ST, I never see this kind of system and the analog imputs are directly connected to source without protection components for the case I've discribed above?
I'm I stupid to do what I do? Is there a risk in the application notes? (You can have a look on AN2390 to see what I mean!).
Could someone from ROUSSEY answer me (in French or in English)?
Waiting for an answer to know if I can save components on my next application,
Regards
whitebull
