Datasheet

DocID14771 Rev 15 67/121
STM8S105x4/6 Electrical characteristics
90
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 startup stabilization time. Refer to the crystal resonator manufacturer for more details
(frequency, package, accuracy...).
Table 32. HSE oscillator characteristics
Symbol Parameter Conditions Min Typ Max Unit
f
HSE
External high speed
oscillator frequency
-1-16MHz
R
F
Feedback resistor - - 220 - k
C
(1)
Recommended load
capacitance
(2)
---20pF
I
DD(HSE)
HSE oscillator power
consumption
C = 20 pF
f
OSC
= 16 MHz
--
6 (start up)
1.6 (stabilized)
(3)
mA
C = 10 pF
f
OSC
= 16 MHz
--
6 (start up)
1.2 (stabilized)
(3)
g
m
Oscillator
transconductance
-5--mA/V
t
SU(HSE)
(4)
Startup time V
DD
is stabilized - 1 - ms
1. C is approximately equivalent to 2 x crystal Cload.
2. The oscillator selection can be optimized in terms of supply current using a high quality resonator with small Rm value.
Refer to crystal manufacturer for more details
3. Data based on characterization results, not tested in production.
4. t
SU(HSE)
is the start-up time measured from the moment it is enabled (by software) to a stabilized 16 MHz oscillation is
reached. This value is measured for a standard crystal resonator and it can vary significantly with the crystal manufacturer.