Electrical characteristics
STM32F103xC, STM32F103xD, STM32F103xE
Low-speed external user clock generated from an external source
The characteristics given in Table 22 result from tests performed using an low-speed
external clock source, and under ambient temperature and supply voltage conditions
summarized in Table 10.
Table 22. 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)
50
Cin(LSE) OSC32_IN input capacitance(1)
5
pF
%
DuCy(LSE) Duty cycle
30
70
1
VSS ≤ VIN ≤ VD
IL
OSC32_IN Input leakage current
µA
D
1. Guaranteed by design, not tested in production.
Figure 20. 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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Doc ID 14611 Rev 8
STMICROELECTRONICS [ ST ]
