DAC8562: Gain and offset error

Hi Sruthi,

This gain error equation is determined by:

1) Find the new slope of the line. You do this by taking a real measurement at 2 different points in the transfer function, ideally close to the start and close to the end. This slope is your Actual LSB. This is variable "m" in the equation.

2) Compare this Actual LSB to the ideal LSB. That's what the 2^n/VREF represents. In this case, your ideal LSB will be the total number of codes (2^n) divided by your total DAC output range (VREF). This can be 2.5V, 5V, 10V, etc... Depends on the DAC. 

3) After this, it's just basic error calculations. Subtract 1 and multiply by 100 to get the %FSR output.

Gain Calibration Ratio:

With this, you need to back-calculate from %FSR into more usable units. This takes the gain error we calculated before, divides by 100 to remove the % that was multiplied in the error equation, then adds 1 to remove the subtraction. This way, you now have a constant that you apply to your code (or reference) to modify the transfer function.

Thanks,
Erin