Electrical characteristics
STM32F103xC, STM32F103xD, STM32F103xE
C
is the pin capacitance and board or trace PCB-related capacitance. Typically, it is
stray
between 2 pF and 7 pF.
Caution:
To avoid exceeding the maximum value of C and C (15 pF) it is strongly recommended
L1
L2
to use a resonator with a load capacitance C 7 pF. Never use a resonator with a load
L
capacitance of 12.5 pF.
Example: if you choose a resonator with a load capacitance of C = 6 pF, and C
= 2 pF,
L
stray
then C = C = 8 pF.
L1
L2
Figure 23. Typical application with a 32.768 kHz crystal
Resonator with
integrated capacitors
C
L1
f
OSC32_IN
LSE
Bias
controlled
gain
32.768 kHz
resonator
R
F
STM32F103xx
OSC32_OUT
C
L2
ai14146
5.3.7
Internal clock source characteristics
The parameters given in Table 25 are derived from tests performed under ambient
temperature and V supply voltage conditions summarized in Table 10.
DD
High-speed internal (HSI) RC oscillator
(1)
Table 25. HSI oscillator characteristics
Symbol
Parameter
Frequency
Conditions
Min
Typ
Max Unit
fHSI
8
MHz
User-trimmed with the RCC_CR
register(2)
1(3)
%
TA = –40 to 105 °C
–2
2.5
2.2
2
%
%
%
%
Accuracy of the HSI
oscillator
ACCHSI
TA = –10 to 85 °C
Factory-
–1.5
–1.3
–1.1
calibrated(4)
TA = 0 to 70 °C
TA = 25 °C
1.8
HSI oscillator
startup time
(4)
tsu(HSI)
1
2
µs
HSI oscillator power
consumption
(4)
IDD(HSI)
80
100
µA
1. VDD = 3.3 V, TA = –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.
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STMICROELECTRONICS [ ST ]
