MSP430FR4131: ADC Conversion

Hi Daviel,

I don't see any specification on the difference between these two. There is typically an absolute max or min value given for VR+ and VR-.  For microcontrollers with a 1.5V internal VREF, the minimum external VR+ is usually around 1.4V with a minimum VR- of around -0.2V.

Hope this helps.

BR,
Leo

but are there any limitation for the resulting (Vr+ - Vr- ) value? Such that if I set Vr+ = 2.0V, and Vr- = 1.9V, the  (Vr+ - Vr- ) = 100mV.  That set the resolution to  100mV/1024 = 97.6uV. 

Will that be true for the ADC input voltage between 1.9V and 2.0V?

Can a difference of 1.2V will work since this this spec isn't in the Data sheet? 

I need to defer to the TI folk on this one. I'm not even quite sure what the symptom would be, maybe some non-linearity out at the edges of the range?

I suppose you could just try it.

Hi Leo,

I see the FR5739 also has a 10-bit SAR ADC, and is an FRAM device, so can we use that as a guide here?  Is it the same ADC in FR413x?  (Similar thinking to Bruce's comment below).  

The FR5739 spec's the Veref difference at 1.4V Minimum.  See datasheet section 5.32.

Thanks,
Darren