STM32F103x8, STM32F103xB
Figure 25. Typical application with a 32.768 kHz crystal
Electrical characteristics
Resonator with
integrated capacitors
CL1
OSC32_IN
32.768 kH z
resonator
CL2
RF
OSC32_OU T
Bias
controlled
gain
STM32F103xx
fLSE
ai14146
5.3.7
Internal clock source characteristics
The parameters given in
are derived from tests performed under ambient
temperature and V
DD
supply voltage conditions summarized in
High-speed internal (HSI) RC oscillator
Table 24.
Symbol
f
HSI
DuCy
(HSI)
HSI oscillator characteristics
(1)
Parameter
Frequency
Duty cycle
User-trimmed with the RCC_CR
register
(2)
45
Conditions
Min
Typ
8
55
1
(3)
–2
–1.5
–1.3
–1.1
1
80
2.5
2.2
2
1.8
2
100
Max
Unit
MHz
%
%
%
%
%
%
µs
µA
ACC
HSI
Accuracy of the HSI
oscillator
Factory-
calibrated
(4)
T
A
= –40 to 105 °C
T
A
= –10 to 85 °C
T
A
= 0 to 70 °C
T
A
= 25 °C
t
su(HSI)(4)
I
DD(HSI)(4)
HSI oscillator
startup time
HSI oscillator power
consumption
1. V
DD
= 3.3 V, T
A
= –40 to 105 °C unless otherwise specified.
2. Refer to application note AN2868 “STM32F10xxx internal RC oscillator (HSI) calibration” available from
the ST website www.st.com.
3. Guaranteed by design, not tested in production.
4. Based on characterization, not tested in production.
Doc ID 13587 Rev 14
55/102
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