To answer the question, you'll want to review the LMP90100 dataheet. If you do, you'll notice that it has a bipolar (+/- Vref/Gain) input range. Thus the calculation is right.
hi 2ndhandscope
i want to more information about lmp90100
i cant get it from datasheet. i want to know that how to calculate the voltage from the output code of the lmp 90100?