EFM8UB1 Datasheet, PDF (31/59 Pages) Silicon Laboratories – The EFM8UB1 highlighted features are listed below

EFM8UB1 Data Sheet
Typical Connection Diagrams
EFM8UB1 Device
4.7 µF and 0.1 µF bypass
capacitors required for
each power pin placed as
close to the pins as
possible.
2.2-3.6 V (in)
VREGIN
VDD
GND
Voltage
Regulator
Figure 5.3. Connection Diagram with Voltage Regulator Not Used
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