The on board voltage regulator lends itself for use in powering more than just certain power pins on the EFR32 itself. Typically the DC-DC is recommended for powering the EFR32 RFVDD, DVDD and sometimes the PAVDD power pins (for desired transmit power levels 13 dBm and lower). There may also be custom applications where it is appropriate to use the DC-DC regulated output for powering additional EFR32 power supply pins or even other device power pins. In cases where the DC-DC is to be used for powering peripherals and / or the IOVDD supply, the designer should:
Note that all validation testing has been at 1.8V and therefore datasheet parameters may be different for DC-DC outputs other than 1.8 V.
Some EFR32 Series 1 and Series 2 variants DC-DC default to Bypass mode coming out of RESET and remain in Bypass mode until software enables the DC-DC. Bypass mode effectively shorts the main supply to the DC-DC output pin. Review the datasheet for the particular EFR32 part number to verify the DC-DC default operation coming out of RESET.
If one of the peripheral devices is also an EFR32, do not power that EFR32’s DVDD pin, due to DVDD will short to AVDD internally upon exiting reset and cause a potential over-current situation for the source DC-DC.
When done, Silicon Labs recommends you submit your finalized design for review in the customer portal.