MSP430F6736A: Understanding SD24 Datasheet

Hello William,

To clarify this, the maximum voltage that can be applied to a pin is defined by the the VI parameter. (AVcc- [AVss -1V]). Max voltage range applied tot he differential pins to ensure full scale range is (-Vref/GAIN) to (+Vref/GAIN) which is defined by VID,FS. (This is slightly different for external reference as noted by note 2. It comes down to 80% of the reference.) The VID parameter defines the max voltage differential within your inputs for a specific gain.

In your example of a gain of 1, the absolute voltage of the positive input can be 1.2V, but your negative side input couldn't go lower than 290mV. Ideally, you would center range so you can go +/- on each side of what your max differential would be, and choose a gain appropriately to measure that max differential.

For example, if you know that the max differential of your signal will never exceed, but can get up to 300mV, then you would choose a GAIN setting of 2, as a GAIN of 3 would not guarantee you FSR.