External VCAP on PIC16F
According to the datasheet, the use of an external capacitor on any VCAP pin is recommended, but not required. In which situation is an external capacitor recommended?
The Capacitor on VCAP is necessary to maintain a stable internal voltage, specifically during internal voltage transients caused by:
- Wake up from sleep at high speeds (32 MHz)
- Clock switching from internal to external clock
- High current outputs due to driving external circuits
- EC clock mode bursts
Basically, any situation that may cause a transient within the core of the device can cause the LDO to destabilize momentarily. These are the situations where VCAP is highly recommended.