I'm using a PMC330 in differential, +-10V mode. The documentation states that to be able to input signals using the full +-10V range an external +-15V PS is needed. In my test stand I don't have a +-15V PS so I'm just using the internal (VME) +-12V PS. I hooked a signal generator up to one of the differential inputs and slowly increased the amplitude of the test signal expecting to see the ADC begin to clip at around 8.5V (as the documentation says it will). However, it never clips. I am able to input a full +-10V signal and clipping never occurs.
Is this unusual? Do I actually need the external +-15V PS (it would be nice not to need one)?