How to read a wider range of voltages into the SA ADC on a PSoC4?
A resistive divider in series with a (suitably wideband, as required by your application) op-amp configured as a voltage follower for impedance matching will do what you need, as long as your signal is entirely DC.  The resistor values in the following circuit will turn a 0-10V signal into a 0-2.04V signal.







simulate this circuit &ndash; Schematic created using CircuitLab

If you actually mean "a 10V peak to peak AC signal" then the circuit will require some revision.

Yes, you will have to sacrifice precision.  A 12-bit ADC has 4096 quantization steps.  If you apply a 3V signal, each step covers ~0.73mV.  If you apply a 10V signal, each step covers ~2.44mV.