Silicon Laboratories C8051T620/2-DK User Manual page 17

7.10. Using Alternate Supplies with the C8051T62x Development Kit
For most evaluation purposes, the onboard 3.3 V supply regulator is sufficient to be used as a VDD power supply.
However, in applications where a different supply voltage is desired (e.g., 1.8 V), an external supply voltage can be
applied to the board at the analog connector (J1). Some devices in the C8051T62x/32x family also support a
separate voltage input for the input/output voltage of the port pins. This Voltage Input/Output (VIO) should be input
to J1 on Pin 2. See the C8051T620-21_T320-3 or C8051T620-23_T326-27 data sheet for more information about
VIO usage and constraints.
Notes:
 When programming a C8051T62x/32x device, VDD must be at least 3.3 V. VDD can be supplied directly to the
device, or the on-chip 5 V regulator can be used.
 If an external supply voltage is desired, the shorting block on J6 should be placed so that the Pin 3 (VDD_EXT)
is shorted to Pin 4 (VDD_PWR).
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