Datasheet

Electrical characteristics STM32L071xx
78/144 DS10690 Rev 6
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 Section 6.3.12. However, the
recommended clock input waveform is shown in Figure 20.
Figure 20. High-speed external clock source AC timing diagram
Table 42. High-speed external user clock characteristics
(1)
1. Guaranteed by design.
Symbol Parameter Conditions Min Typ Max Unit
f
HSE_ext
User external clock source
frequency
CSS is ON or
PLL is used
1832MHz
CSS is OFF,
PLL not used
0832MHz
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(HSE)
t
w(HSE)
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
--±1µA
ai18232c
OSC _IN
EXTERNAL
STM32Lxx
CLOCK SOURC E
V
HSEH
t
f(HSE)
t
W(HSE)
I
L
90%
10%
T
HSE
t
t
r(HSE)
t
W(HSE)
f
HSE_ext
V
HSEL
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