ST72F324BJ STMICROELECTRONICS [STMicroelectronics], ST72F324BJ Datasheet - Page 145

• Manufacturer Part Number: ST72F324BJ
• Description: 8-bit MCU, 3.8 to 5.5 V operating range with 8 to 32 Kbyte Flash/ROM, 10-bit ADC, 4 timers, SPI, SCI
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

ST72324B
12.6.3
Crystal and ceramic resonator oscillators
The ST7 internal clock can be supplied with four different crystal/ceramic resonator
oscillators. All the information given in this paragraph are 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/ceramic resonator
manufacturer for more details (frequency, package, accuracy...).
8/16 Kbyte Flash and ROM devices
Table 94.
1. The oscillator selection can be optimized in terms of supply current using an high quality resonator with
2. Data based on characterization results, not tested in production. The relatively low value of the RF resistor,
3. For C
Figure 66. Typical application with a crystal or ceramic resonator (8/16 Kbyte Flash
Symbol
f
C
C
OSC
R
small R
offers a good protection against issues resulting from use in a humid environment, due to the induced
leakage and the bias condition change. However, it is recommended to take this point into account if the
microcontroller is used in tough humidity conditions.
designed for high-frequency applications and selected to match the requirements of the crystal or
resonator. C
capacitance which is the series combination of C
included when sizing C
capacitance).
i
2
L1
L2
F
L1
S
When resonator with
integrated capacitors
Oscillator frequency
Feedback resistor
Recommended load capacitance
versus equivalent serial
resistance of the crystal or
ceramic resonator (R
OSC2 driving current
and C
value. Refer to crystal/ceramic resonator manufacturer for more details.
Crystal and ceramic resonator oscillators (8/16K Flash and ROM devices)
and ROM devices)
L1
L2
and C
it is recommended to use high-quality ceramic capacitors in the 5pF to 25pF range (typ.)
Parameter
L2
, are usually the same size. The crystal manufacturer typically specifies a load
L1
C
and C
L2
(2)
C
(1)
L1
S
L2
)
(3)
(10 pF can be used as a rough estimate of the combined pin and board
Resonator
LP: low power oscillator
MP: medium power oscillator
MS: medium speed oscillator
HS: high speed oscillator
R
R
R
R
V
L1
S
S
S
S
DD
and C
= 200Ω
= 200Ω
= 200Ω
= 100Ω
OSC1
OSC2
= 5V, V
L2
Conditions
. PCB and MCU pin capacitance must be
IN
R
F
= V
LP oscillator
MP oscillator
MS oscillator
HS oscillator
LP oscillator
MP oscillator
MS oscillator
HS oscillator
SS
i
2
Electrical characteristics
Min Typ Max Unit
>2
>4
>8
20
22
22
18
15
1
ST72XXX
f
OSC
160
310
610
80
150
250
460
910
16
40
56
46
33
33
2
4
8
145/188
MHz
kΩ
µA
pF