AVR-Chat

--- In AVR-Chat@yahoogroups.com, "Roy E. Burrage" <RBurrage@...> 
wrote:

> Why not just stick with MOSFETs, Graham?

Sure.  An NPN transistor is just an alternative.

> He might also want to use some sort
> of gate/source protection scheme ...

That would depend on the application, which we don't know.

> Why would he not be able to expect
> pretty fair accuracy from your scheme?

He would.  As you say, the on resistance of the MOSFET would be of no 
consequence, so it's just a matter of using the appropriate resistors 
in the divider and a good reference for the ADC.

Some of the other suggestions, though, did not strive for accuracy.  
Again, it may not be necessary in this application.  We don't know 
what the OP hasn't told us.  Recall that his original post didn't 
mention the need to draw almost no power, it was just about what the 
data sheet said about the ADC reference input.

Graham.