Electrical characteristics
STM32L151x6/8/B, STM32L152x6/8/B
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DocID17659 Rev 10
6.3.6 External
clock
source characteristics
High-speed external user clock generated from an external source
In bypass mode the HSE oscillator is switched off and the input pin is a standard GPIO. The
external clock signal has to respect the I/O characteristics in
. However, the
recommended clock input waveform is shown in
Figure 15: High-speed external clock
.
Figure 15. High-speed external clock source AC timing diagram
Table 26. High-speed external user clock characteristics
(1)
1. Guaranteed by design, not tested in production.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
f
HSE_ext
User external clock source
frequency
CSS is on or
PLL is used
1
8
32
MHz
CSS is off, PLL
not used
0
V
HSEH
OSC_IN input pin high level voltage
-
0.7V
DD
-
V
DD
V
V
HSEL
OSC_IN input pin low level voltage
V
SS
-
0.3V
DD
t
w(HSEH)
t
w(HSEL)
OSC_IN high or low time
12
-
-
ns
t
r(HSE)
t
f(HSE)
OSC_IN rise or fall time
-
-
20
C
in(HSE)
OSC_IN input capacitance
-
-
2.6
-
pF
DuCy
(HSE)
Duty cycle
-
45
-
55
%
I
L
OSC_IN Input leakage current
V
SS
≤
V
IN
≤
V
DD
-
-
±1
µA
069
9+6(+
WI+6(
7+6(
W
WU+6(
9+6(/
WZ+6(+
WZ+6(/