Datasheet

Figure 19: HSE external clocksource
V
HSEH
V
HSEL
External clock
source
OSCIN
f
HSE
STM8
HSE crystal/ceramic resonator oscillator
The HSE clock can be supplied with a 1 to 16 MHz crystal/ceramic resonator oscillator. All
the information given in this paragraph is based on characterization results with specified
typical external components. In the application, the resonator and the load capacitors have
to be placed as close as possible to the oscillator pins in order to minimize output distortion
and start-up stabilization time. Refer to the crystal resonator manufacturer for more details
(frequency, package, accuracy...).
Table 33: HSE oscillator characteristics
UnitMaxTypMinConditionsParameterSymbol
MHz161
External high speed
oscillator frequency
f
HSE
kΩ220
Feedback resistorR
F
pF20
Recommended load
capacitance
(2)
C
(1)
mA
6 (startup)
C = 20 pF,
HSE oscillator power
consumption
I
DD(HSE)
1.6 (stabilized)
(3)
f
OSC
= 16 MHz
6 (startup)
C = 10 pF,
1.2 (stabilized)
(3)
f
OSC
=16 MHz
mA/V5
Oscillator
transconductance
g
m
ms1
V
DD
is stabilizedStartup timet
SU(HSE)
(4)
(1)
C is approximately equivalent to 2 x crystal Cload.
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STM8S105xxElectrical characteristics