When the OPAMP is used in combination with
the ADC, the OPAMP offset and gain errors can be compensated. To calculate offset and gain
error compensation values
- 1.Configure OPAMP as Voltage
Follower
- 2.Route the OPAMP output to the ADC:
- Write a '1' to the Analog
Output bit in the Operational Amplifier x Control register
(OPAMPCTRLx.ANAOUT)
- Select the OPAMP as input for
the ADC, see ADC – Analog-to-Digital Converter.
- 3.Measure and set the Offset Correction
value for the ADC OFFSETCORR register as in Offset Compensation.
- 4.Measure and set the Gain Correction value for the ADC GAINCORR register as in Gain Compensation.
The offset error compensation must be determined before gain error compensation.
The relation for offset and gain error compensation is shown in this
equation:
Result = (converted value +
OFFSETCORR)*GAINCORR