Electrical characteristics
STM32F103x8, STM32F103xB
5.3.6
External clock source characteristics
High-speed external user clock generated from an external source
The characteristics given in Table 20 result from tests performed using an high-speed
external clock source, and under ambient temperature and supply voltage conditions
summarized in Table 9.
Table 20. High-speed external user clock characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
User external clock source
frequency(1)
fHSE_ext
1
8
25
MHz
VHSEH
VHSEL
tw(HSE)
OSC_IN input pin high level voltage
OSC_IN input pin low level voltage
0.7VDD
VSS
VDD
V
0.3VDD
OSC_IN high or low time(1)
OSC_IN rise or fall time(1)
16
45
tw(HSE)
ns
tr(HSE)
tf(HSE)
20
Cin(HSE) OSC_IN input capacitance(1)
5
pF
%
DuCy(HSE) Duty cycle
55
1
IL
OSC_IN Input leakage current
VSS VIN VDD
µA
1. Guaranteed by design, not tested in production.
Low-speed external user clock generated from an external source
The characteristics given in Table 21 result from tests performed using an low-speed
external clock source, and under ambient temperature and supply voltage conditions
summarized in Table 9.
Table 21. Low-speed external user clock characteristics
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
User External clock source
frequency(1)
fLSE_ext
32.768
1000
kHz
OSC32_IN input pin high level
voltage
VLSEH
VLSEL
0.7VDD
VSS
VDD
V
OSC32_IN input pin low level
voltage
0.3VDD
tw(LSE)
tw(LSE)
OSC32_IN high or low time(1)
OSC32_IN rise or fall time(1)
450
ns
tr(LSE)
tf(LSE)
50
Cin(LSE) OSC32_IN input capacitance(1)
5
pF
%
DuCy(LSE) Duty cycle
30
70
1
OSC32_IN Input leakage
current
IL
VSS VIN VDD
µA
1. Guaranteed by design, not tested in production.
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