Datasheet
DocID17943 Rev 6 89/134
STM8L15xx8, STM8L15xR6 Electrical parameters
121
LSE external clock (LSEBYP=1 in CLK_ECKCR)
The LSE is available on STM8L151xx and STM8L152xx devices only.
Subject to general operating conditions for V
DD
and T
A
.
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 30. LSE external clock characteristics
Symbol Parameter Min. Typ. Max. Unit
f
LSE_ext
(1)
External clock source frequency 32.768 kHz
V
LSEH
(2)
OSC32_IN input pin high level voltage 0.7 x V
DD
V
DD
V
V
LSEL
(2)
OSC32_IN input pin low level voltage V
SS
0.3 x V
DD
C
in(LSE)
(1)
OSC32_IN input capacitance 0.6 pF
I
LEAK_LSE
OSC32_IN input leakage current ±1 µA
1. Guaranteed by design, not tested in production.
2. Data based on characterization results, not tested in production.
Table 31. HSE oscillator characteristics
Symbol Parameter Conditions Min. Typ. Max. Unit
f
HSE
High speed external oscillator
frequency
116MHz
R
F
Feedback resistor 200 kΩ
C
(1)(2)
Recommended load capacitance 20 pF
I
DD(HSE)
HSE oscillator power consumption
C = 20 pF,
f
OSC
= 16 MHz
2.5 (startup)
0.7 (stabilized)
(3)
mA
C = 10 pF,
f
OSC
=16 MHz
2.5 (startup)
0.46 (stabilized)
(3)
g
m
Oscillator transconductance 3.5
(3)
mA/V
t
SU(HSE)
(4)
Startup time V
DD
is stabilized 1 ms
1. C=
C
L1
=
C
L2
is approximately equivalent to 2 x crystal C
LOAD
.
2. The oscillator selection can be optimized in terms of supply current using a high quality resonator with small R
m
value.
Refer to crystal manufacturer for more details
3. Guaranteed by design. Not tested in production.
4. t
SU(HSE)
is the startup time measured from the moment it is enabled (by software) to a stabilized 16 MHz oscillation. This
value is measured for a standard crystal resonator and it can vary significantly with the crystal manufacturer.