Cirrus Logic CRD5490 - Manual (Page 20)

CRD5490-Z
20 DS988RD1
AC Offset Calibrations
For AC offset calibration, the CRD5490-Z software clears the offset register before calibration begins. The gain
register values are not modified by the software, and the current configuration is used from the prior gain calibration.
AC calibration only affects the current channel's I
RMS
value.
1. Continue from step 13 in the Gain Calibration section on page 16 and keep the AC source on.
2. Remove the AC load.
3. Open the Quick Measurements tab and click the START button.
4. Wait approximately 5 to 10 seconds for readings to update.
5. Click the STOP button.
6. Confirm that the current is as expected during a no-load condition. Inspect the pre-calibrated I
RMS
closely.
7. Click the Calibration tab to bring it forward, and click the AC Offset Calibration button.
Figure 22. Quick Measurements Tab - Note I
RMS
before AC Offset Calibration