The biggest difference between the parts shown here is the core voltage regulator. The PIC24F16KA102 does not use a core voltage regulator, the entire device runs at full VDD voltage. In contrast, the PIC18F46J50/11 and PIC24FJ64GA104 use a separate core voltage, lowering power use of the processor core logic. Deep Sleep mode on these devices turns off the processor core by disabling the internal core voltage regulator. For PIC18, the LF variants of these devices lack the internal core voltage regulator; consequently, Deep Sleep mode is not available on LF parts. For the PIC24, the voltage regulator enable/disable pin must be enabled for Deep Sleep Mode.