Datasheet

Electrical characteristics STM32F303xB STM32F303xC
74/133 DocID023353 Rev 7
6.3.7 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 6.3.14. However, the
recommended clock input waveform is shown in Figure 13.
Figure 13. High-speed external clock source AC timing diagram
Table 38. High-speed external user clock characteristics
Symbol Parameter Conditions Min Typ Max Unit
f
HSE_ext
User external clock source
frequency
(1)
1. Guaranteed by design, not tested in production.
1832MHz
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
(1)
15 - -
ns
t
r(HSE)
t
f(HSE)
OSC_IN rise or fall time
(1)
--20
MS19214V2
V
HSEH
t
f(HSE)
90%
10%
T
HSE
t
t
r(HSE)
V
HSEL
t
W(HSEH)
t
W(HSEL)