EFM32WG990 Datasheet, PDF (31/85 Pages) List of Unclassifed Manufacturers – The EFM32 MCUs are the world’s most energy friendly microcontrollers.

...the world's most energy friendly microcontrollers
Figure 3.22. Calibrated HFRCO 21 MHz Band Frequency vs Supply Voltage and Temperature
21.2
21.2
21.0
21.0
20.8
20.8
20.6
20.6
20.4
- 40°C
25°C
85°C
20.2
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8
Vdd [V]
20.4
20.2
–4 0
2.0 V
3.0 V
3.8 V
–1 5
5
25
45
65
85
Tem perature [°C]
Figure 3.23. Calibrated HFRCO 28 MHz Band Frequency vs Supply Voltage and Temperature
28.2
28.0
27.8
27.6
27.4
27.2
27.0
- 40°C
25°C
85°C
26.8
2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8
Vdd [V]
28.4
28.2
28.0
27.8
27.6
27.4
27.2
27.0
26.8
–4 0
2.0 V
3.0 V
3.8 V
–1 5
5
25
45
65
85
Tem perature [°C]
2014-06-13 - EFM32WG990FXX - d0203_Rev1.40
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