STM32F103xC, STM32F103xD, STM32F103xE
Low-speed external user clock
Electrical characteristics
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
tw(LSE)
0.7VDD
VSS
VDD
V
OSC32_IN input pin low level
voltage
0.3VDD
OSC32_IN high or low time(1)
OSC32_IN rise or fall time(1)
450
tw(LSE)
ns
tr(LSE)
tf(LSE)
5
1
OSC32_IN Input leakage
current
IL
VSS ≤VIN ≤VDD
µA
1. Value based on design simulation and/or technology characteristics. It is not tested in production.
Figure 18. High-speed external clock source AC timing diagram
V
HSEH
90%
10%
V
HSEL
t
t
t
W(HSE)
t
t
W(HSE)
r(HSE)
f(HSE)
T
HSE
f
HSE_ext
EXTERNAL
CLOCK SOURCE
I
L
OSC _IN
STM32F103xx
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STMICROELECTRONICS [ ST ]
