No. The input voltage cannot be higher than the analog supply voltage. But you might use a voltage divider to reduce the range of your input voltage.
... and of course the Vref may not exceed analog supply.
The consequences of using 3.3 V but desiring 5 V ADC range
in a multichannel design would require an (R) attenuator on
each input. Or use an external mux with 3.3 V control drive,
5V input range followed by a single attenuator. So you would
have to do an error budget to determine if design meets your
goals in any event.
If all you have as a power source, 3.3 V, as a source, consider a
boost converter, many offerings from various vendors, from sw cap
designs to L based boost converters. Note some PSOC's have
an internal boost converter, PSOC 1 & 3.
Also datasheet incomplete regarding relationship of Vssa, Vss and
Here are simple charge pump converter examples, just an external C required
for many. ~ 50 to 80 cent kinds of parts.
One other consideration to using R dividers, is impact on
signal loading of the measurement node you are examining,
and of course speed and settling time impact on SAR opera-
All this can be largely mitigated by operating part at 5V. Or
use PSOC 1 or 3 with internal boost converters.