vref FVR and ADC10
- Thread starter hax
- Start date
1.024V should not be used as it is below the 1.8V minimum Vref of the ADC silicon
http://www.picaxeforum.co.uk/showthread.php?27307-vref-confusion
http://www.picaxeforum.co.uk/showthread.php?27307-vref-confusion
Hi Haxby,
yes a good question I dont recall it being in the specs (pin usually VDD plus 0.3v the limit)
But when Vref is lower then Vdd I think there's mention of caution of reducing current when switching between analog and digital(you could add a series resistor)
so I wouldnt like to go above Vref plus 0.3(max).
When using FVR1024 a minimum VDD of 2.5v for voltage gain accuracy is required.
and to reduce errors from leakage current you may need to lower your impedance(5k)
usually adding a 0.01 capacitor is enough.
yes a good question I dont recall it being in the specs (pin usually VDD plus 0.3v the limit)
But when Vref is lower then Vdd I think there's mention of caution of reducing current when switching between analog and digital(you could add a series resistor)
so I wouldnt like to go above Vref plus 0.3(max).
When using FVR1024 a minimum VDD of 2.5v for voltage gain accuracy is required.
and to reduce errors from leakage current you may need to lower your impedance(5k)
usually adding a 0.01 capacitor is enough.