The +1.2V for VDDCR is supplied by the on-chip regulator unless the transceiver is configured for theregulator off mode using the REGOFF configuration strap as described in Section 3.7.3.1. By default, the internal +1.2V regulator is enabled when REGOFF is floating (due to the internal pull-down resistor).
During power-on, if REGOFF is sampled below V IL , then the internal +1.2V regulator will turn on and operate with power from the VDD2A pin.