EFM32WG395 Datasheet, PDF (27/82 Pages) List of Unclassifed Manufacturers – The EFM32 MCUs are the world’s most energy friendly microcontrollers.

3.9 Oscillators
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3.9.1 LFXO
Table 3.9. LFXO
Symbol
Parameter
Condition
Min
Typ
Max
Unit
f_LFXO
Supported nominal
crystal frequency
32.768
kHz
ESR_LFXO
C_LFXOL
Supported crystal
equivalent series re-
sistance (ESR)
Supported crystal
external load range
30
120 kOhm
X¹
25 pF
I_LFXO
Current consump-
tion for core and
buffer after startup.
ESR=30 kOhm, C_L=10 pF,
LFXOBOOST in CMU_CTRL is
1
190
nA
t_LFXO
Start- up time.
ESR=30 kOhm, C_L=10 pF,
40% - 60% duty cycle has
been reached, LFXOBOOST in
CMU_CTRL is 1
400
ms
1_{See Minimum Load Capacitance (CLFXOL) 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".
3.9.2 HFXO
Table 3.10. HFXO
Symbol
f_HFXO
ESR_HFXO
g_mHFXO
C_HFXOL
I_HFXO
t_HFXO
Parameter
Condition
Min
Supported nominal
crystal Frequency
Supported crystal
equivalent series re-
sistance (ESR)
Crystal frequency 48 MHz
Crystal frequency 32 MHz
Crystal frequency 4 MHz
The transconduc-
tance of the HFXO
input transistor at
crystal startup
HFXOBOOST in CMU_CTRL
equals 0b11
Supported crystal
external load range
Current consump-
tion for HFXO after
startup
4 MHz: ESR=400 Ohm,
C_L=20 pF, HFXOBOOST in
CMU_CTRL equals 0b11
32 MHz: ESR=30 Ohm,
C_L=10 pF, HFXOBOOST in
CMU_CTRL equals 0b11
Startup time
32 MHz: ESR=30 Ohm,
C_L=10 pF, HFXOBOOST in
CMU_CTRL equals 0b11
Typ
4
20
5
Max
Unit
48 MHz
50 Ohm
30
60 Ohm
400
1500 Ohm
mS
25 pF
85
µA
165
µA
400
µs
2014-06-13 - EFM32WG395FXX - d0194_Rev1.40
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