ST10F272M-4Q3 STMICROELECTRONICS [STMicroelectronics], ST10F272M-4Q3 Datasheet - Page 149

• Manufacturer Part Number: ST10F272M-4Q3
• Description: 16-bit MCU with 256 Kbyte Flash memory and 20 Kbyte RAM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST10F272M
24.8.12
32 kHz oscillator specifications
V
Table 66.
1. At power-on a high current biasing is applied for faster oscillation start-up. Once the oscillation is started,
2. Not 100% tested, guaranteed by design characterization.
Figure 48. 32 kHz crystal oscillator connection diagram
Table 67.
The given values of C
printed circuit board: the negative resistance values are calculated assuming additional 5pF
to the values in the table. The crystal shunt capacitance (C
between XTAL3 and XTAL4 pins is globally assumed equal to 4pF. The external resistance
between XTAL3 and XTAL4 is not necessary, since already present on the silicon.
Frequency
Symbol
t
V
DD
STUP32
V
g
OSC32
32 kHz
the current biasing is reduced to lower the power consumption of the system.
AV32
m32
= 5V ± 10%, V
Warning:
Oscillator Transconductance
Oscillation Amplitude
Oscillation Voltage level
Oscillator Start-up Time
32 kHz oscillator characteristics
Minimum values of negative resistance (module) for 32 kHz oscillator
C
A
= 6pF
-
Parameter
SS
Direct driving on XTAL3 pin is not supported. Always use a
32 kHz crystal oscillator.
A
= 0V, T
do not include the stray capacitance of the package and of the
C
A
= 12pF C
-
(2)
A
= -40 to +125°C
(2)
(2)
(1)
A
= 15pF C
Start-up
Normal run
Peak to Peak
Sine wave middle
Stable V
ST10F272M
-
C
A
Crystal
Conditions
DD
A
= 18pF C
-
C
A
0
Min
A
) and the package capacitance
150 kΩ
0.5
0.7
20
8
–
= 22pF C
Electrical characteristics
Value
Typ
1.0
0.9
31
17
1
A
120 kΩ
= 27pF C
Max
2.4
1.2
50
30
5
A
90 kΩ
= 33pF
149/176
µA/V
µA/V
Unit
V
V
s