I experiment with the PIC24 series of μCs fairly often and have noticed that I can run them successfully from a 3.7v LiPo battery pack without a regulator. The batteries charge to around 4.2v fully charged and down to a little below 3.7v drained. This is only slightly above the suggested 3.3v. I just wondered if there are any side-effects of this? Does it affect the internal oscillators or some other internal processes? Or is the effect negligible?
The datasheet warns:
Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device.
But can you use a voltage above 3.6 V, but still below the absolute maximum ratings?
This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied.
No; it's still not guaranteed to work.
But does this at least avoid the "permanent damage" mentioned above?
Exposure to Absolute Maximum Rating conditions for extended periods may affect device reliability.
No; you still can damage your device, it will just not happen immediately.
But what will actually happen? This is impossible to predict exactly; any part of the µC might fail, fully or partially.