5.2 SAR ADC

The BM83 module has a 10-bit Successive Approximation Register (SAR) ADC with ENOB (Effective Number of Bits) of 8-bits; used for battery voltage detection, adapter voltage detection, charger thermal protection, and ambient temperature detection. The input power of the SAR ADC is supplied by the 1.8V output of Buck2. The warning level can be programmed by using the Config Tool or the SDK.

The SK1 and SK2 are the ADC channel pins. The SK1 is used for charger thermal protection. The following figure illustrates the suggested circuit and thermistor, Murata NCP15WF104F. The charger thermal protection can avoid battery charge in a restricted temperature range. The upper and lower limits for temperature values can be configured by using the Config Tool.
Figure 5-3. Ambient Detection Circuit
Note: The thermistor must be placed close to the battery in the user application for accurate temperature measurements and to enable the thermal shutdown feature.

The following figures show SK1 and SK2 channel behavior.

Figure 5-4. SK1 Channel
Figure 5-5. SK2 Channel