[RC232] Using a switching power supply from 12V to 3.3V, switching at 300 kHz, and a 1% ripple output; do I need extra filtering?
Inside the module we have only a 2u2 cap close to the VCC pins. The Radio part has an internal regulator but the Power Amplifier stages has not. For this reason a switching power might influence on performance and additional filtering should be added. Testing will inform if additional filtering is needed in your design.