Internal Clock Source Characteristics; Figure 16. Typical Application With A 32.768 Khz Crystal - STMicroelectronics STM32F038C6 Manual

Electrical characteristics
Table 32. LSE oscillator characteristics (f
Symbol Parameter
Oscillator
g
m
transconductance
(3)
t Startup time
SU(LSE)
1. Refer to the note and caution paragraphs below the table, and to the application note AN2867 "Oscillator design guide for
ST microcontrollers".
2. Guaranteed by design, not tested in production.
3. t is the startup time measured from the moment it is enabled (by software) to a stabilized 32.768 kHz oscillation is
SU(LSE)
reached. This value is measured for a standard crystal and it can vary significantly with the crystal manufacturer
Note: For information on selecting the crystal, refer to the application note AN2867 "Oscillator
design guide for ST microcontrollers" available from the ST website www.st.com.
Note: An external resistor is not required between OSC32_IN and OSC32_OUT and it is forbidden
to add one.
6.3.7

Internal clock source characteristics

The parameters given in
temperature and supply voltage conditions summarized in
conditions. The provided curves are characterization results, not tested in production.
56/102
Conditions
LSEDRV[1:0]=00
lower driving capability
LSEDRV[1:0]= 01
medium low driving capability
LSEDRV[1:0] = 10
medium high driving capability
LSEDRV[1:0]=11
higher driving capability
V
DDIOx

Figure 16. Typical application with a 32.768 kHz crystal

Table 33 are derived from tests performed under ambient
DocID026079 Rev 3
= 32.768 kHz)
LSE
(1)
is stabilized
Table 18: General operating
STM32F038x6
(2) (2)
Min Typ Max
5 - -
8 - -
15 - -
25 - -
- 2 -
Unit
µA/V
s