The Analog-to-Digital RC (ADCRC) oscillator is dedicated to the ADC module. This oscillator is also referred to as the FRC clock. The ADCRC operates at a fixed frequency of approximately 600 kHz, and is used as a conversion clock source. The ADCRC allows the ADC module to operate in Sleep mode, which can reduce system noise during the ADC conversion. The ADCRC is automatically enabled when it is selected as the clock source for the ADC module, or when selected as the clock source of any peripheral that may use it. The ADCRC may also be manually enabled via the ADC Oscillator Enable (ADOEN) bit, thereby avoiding start-up delays when this source is used intermittently.