Datasheet

Electrical characteristics STM32F405xx, STM32F407xx
100/202 DocID022152 Rev 8
Low-speed external user clock generated from an external source
The characteristics given in Table 31 result from tests performed using an low-speed
external clock source, and under ambient temperature and supply voltage conditions
summarized in
Table 14.
Figure 30. High-speed external clock source AC timing diagram
Table 31. Low-speed external user clock characteristics
Symbol Parameter Conditions Min Typ Max Unit
f
LSE_ext
User External clock source
frequency
(1)
-
- 32.768 1000 kHz
V
LSEH
OSC32_IN input pin high level
voltage
0.7V
DD
-V
DD
V
V
LSEL
OSC32_IN input pin low level voltage V
SS
-0.3V
DD
t
w(LSE)
t
f(LSE)
OSC32_IN high or low time
(1)
450 - -
ns
t
r(LSE)
t
f(LSE)
OSC32_IN rise or fall time
(1)
--50
C
in(LSE)
OSC32_IN input capacitance
(1)
--5-pF
DuCy
(LSE)
Duty cycle - 30 - 70 %
I
L
OSC32_IN Input leakage current V
SS
≤ V
IN
≤ V
DD
--±1µA
1. Guaranteed by design.
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