What is the VDD requirement of the Si4356 radio chip?
Supply voltage range: 1.8 - 3.6 V
The Power-On-Reset sequence should be also followed for the proper operation as in case of Si4355.
"A Power-On-Reset (POR) sequence is used to boot the device up from a fully off or shutdown state. To execute this process, VDD must ramp within 1ms and must remain applied to the device for at least 10ms. If VDD is removed, then it must stay below 150mV for at least 10ms before being applied again."