EFM32GG232 Datasheet, PDF (26/71 Pages) Silicon Laboratories – High Performance 32-bit processor

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Figure 3.16. Calibrated HFRCO 28 MHz Band Frequency vs Supply Voltage and Temperature
28.2
28.0
27.8
27.6
27.4
27.2
- 40°C
25°C
85°C
27.0
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
–4 0
2.0 V
3.0 V
3.8 V
–1 5
5
25
45
65
85
Tem perature [°C]
3.9.5 AUXHFRCO
Table 3.12. AUXHFRCO
Symbol
Parameter
Condition
Min
Typ
Max
Unit
28 MHz frequency band
27.5
28.0
28.5 MHz
21 MHz frequency band
20.6
21.0
21.4 MHz
f_AUXHFRCO
Oscillation frequen-
cy, V_DD= 3.0 V,
T_AMB=25°C
14 MHz frequency band
11 MHz frequency band
7 MHz frequency band
1 MHz frequency band
13.7
10.8
6.48¹
1.15²
14.0
11.0
6.60¹
1.20²
14.3 MHz
11.2 MHz
6.72¹ MHz
1.25² MHz
t_{AUXHFRCO_settling}Settling time after
start-up
f_AUXHFRCO = 14 MHz
0.6
Cycles
DC_AUXHFRCO Duty cycle
f_AUXHFRCO = 14 MHz
48.5
50
51 %
TUNESTEP_AUX-Frequency step
HFRCO
for LSB change in
TUNING value
0.3³
%
1_{For devices with prod. rev. < 19, Typ = 7MHz and Min/Max values not applicable.}
2_{For devices with prod. rev. < 19, Typ = 1MHz and Min/Max values not applicable.}
3_{The TUNING field in the CMU_AUXHFRCOCTRL register may be used to adjust the AUXHFRCO frequency. There is enough}
adjustment range to ensure that the frequency bands above 7 MHz will always have some overlap across supply voltage and
temperature. By using a stable frequency reference such as the LFXO or HFXO, a firmware calibration routine can vary the
TUNING bits and the frequency band to maintain the AUXHFRCO frequency at any arbitrary value between 7 MHz and 28 MHz
across operating conditions.
2016-03-21 - EFM32GG232FXX - d0125_Rev1.40
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