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2013-06-28 - EFM32G230FXX - d0005_Rev1.60
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3.9 Oscillators
3.9.1 LFXO
Table 3.9. LFXO
Symbol
Parameter
Condition
Min
Typ
Max
Unit
fLFXO
Supported nominal crystal
frequency
32.768
kHz
ESRLFXO
Supported crystal equiv-
alent series resistance
(ESR)
30
120
kOhm
CLFXOL
Supported crystal external
load range
X
1
25
pF
DCLFXO
Duty cycle
48
50
53.5
%
ILFXO
Current consumption for
core and buffer after start-
up.
ESR=30 kOhm, CL=10 pF,
LFXOBOOST in CMU_CTRL
is 1
190
nA
tLFXO
Start- up time.
ESR=30 kOhm, CL=10 pF,
40% - 60% duty cycle has
been reached, LFXOBOOST
in CMU_CTRL is 1
400
ms
1See Minimum Load Capacitance (C
LFXOL) Requirement For Safe Crystal Startup in energyAware Designer in Simplicity Studio
For safe startup of a given crystal, the energyAware Designer in Simplicity Studio contains a tool to help
users configure both load capacitance and software settings for using the LFXO. For details regarding
the crystal configuration, the reader is referred to application note "AN0016 EFM32 Oscillator Design
Consideration".