EFR32FG12 Datasheet, PDF (72/183 Pages) –

4.1.12 Oscillators
4.1.12.1 Low-Frequency Crystal Oscillator (LFXO)
EFR32FG12 Flex Gecko Proprietary Protocol SoC Family Data Sheet
Electrical Specifications
Table 4.33. Low-Frequency Crystal Oscillator (LFXO)
Parameter
Symbol
Test Condition
Min
Typ
Max
Unit
Crystal frequency
f_LFXO
—
32.768
—
kHz
Supported crystal equivalent ESR_LFXO
series resistance (ESR)
—
—
70
kΩ
Supported range of crystal
load capacitance ¹
C_{LFXO_CL}
6
—
18
pF
On-chip tuning cap range ^{2 C}LFXO_T
On each of LFXTAL_N and
LFXTAL_P pins
8
—
40
pF
On-chip tuning cap step size SS_LFXO
—
0.25
—
pF
Current consumption after
startup ³
I_LFXO
ESR = 70 kOhm, C_L = 7 pF,
GAIN⁴ = 2, AGC⁴ = 1
—
273
—
nA
Start- up time
t_LFXO
ESR = 70 kOhm, C_L = 7 pF,
GAIN⁴ = 2
—
308
—
ms
Note:
1. Total load capacitance as seen by the crystal.
2. The effective load capacitance seen by the crystal will be C_{LFXO_T} /2. This is because each XTAL pin has a tuning cap and the
two caps will be seen in series by the crystal.
3. Block is supplied by AVDD if ANASW = 0, or DVDD if ANASW=1 in EMU_PWRCTRL register.
4. In CMU_LFXOCTRL register.
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