Datasheet
Electrical characteristics STM32F334x4 STM32F334x6 STM32F334x8
68/121 DocID025409 Rev 8
Note: For information on selecting the crystal, refer to the application note AN2867 “Oscillator
design guide for ST microcontrollers” available at the ST website www.st.com.
Figure 17. Typical application with a 32.768 kHz crystal
Note: An external resistor is not required between OSC32_IN and OSC32_OUT and it is forbidden
to add one.
6.3.8 Internal clock source characteristics
The parameters given in Table 40 are derived from tests performed under ambient
temperature and supply voltage conditions summarized in Table 19.
g
m
Oscillator
transconductance
LSEDRV[1:0]=00
lower-driving capability
5- -
µA/V
LSEDRV[1:0]=10
medium low-driving
capability
8- -
LSEDRV[1:0]=01
medium high-driving
capability
15 - -
LSEDRV[1:0]=11
higher-driving capability
25 - -
t
SU(LSE)
(3)
Startup time V
DD
is stabilized - 2 - s
1. Refer to the note and caution paragraphs below the table, and to the application note AN2867 “Oscillator
design guide for ST microcontrollers”.
2. Guaranteed by design, not tested in production.
3. t
SU(LSE)
is the startup time measured from the moment it is enabled (by software) to a stabilized
32.768 kHz oscillation is reached. This value is measured for a standard crystal and it can vary significantly
with the crystal manufacturer.
Table 39. LSE oscillator characteristics (f
LSE
= 32.768 kHz) (continued)
Symbol Parameter Conditions
(1)
Min.
(2)
Typ. Max.
(2)
Unit
MS19876V1
(1)
OSC_IN
OSC_OUT
R
F
Bias
controlled
gain
f
HSE
R
EXT
8 MHz
resonator
Resonator with integrated
capacitors
C
L1
C
L2
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