ADF7021 RFout Voltage

I have a customer who is currently powering the ADF7021 Vdd and RFout with a 3.0V supply. 

They may need to power the RFout with 3.3V. Since the RFout is open collector, is it possible to use a higher voltage on RFout than Vdd or is there something internal that prevents this configuration? 

Thanks,

Mike