ST72321B STMICROELECTRONICS [STMicroelectronics], ST72321B Datasheet - Page 146

• Manufacturer Part Number: ST72321B
• Description: 64/44-pin 8-bit MCU with 32 to 60K Flash/ROM, ADC, five timers, SPI, SCI, I2C interface
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

CLOCK AND TIMING CHARACTERISTICS (Cont’d)
12.5.3 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 is based on
characterization results with specified typical ex-
ternal components. In the application, the resona-
tor and the load capacitors have to be placed as
Notes:
1. The oscillator selection can be optimized in terms of supply current using an high quality resonator with small R
Refer to crystal/ceramic resonator manufacturer for more details.
2. Data based on characterisation results, not tested in production.
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f
R
C
C
i
2
OSC
Symbol
Symbol
F
L1
L2
Oscillator Frequency
Feedback resistor
Recommended load capacitance ver-
sus equivalent serial resistance of the
crystal or ceramic resonator (R
OSC2 driving current
Parameter
Parameter
2)
1)
V
V
DD
IN
S
)
=V
=5V
SS
LP: Low power oscillator
MP: Medium power oscillator
MS: Medium speed oscillator
HS: High speed oscillator
R
R
R
R
S
S
S
S
=200Ω
=200Ω
=200Ω
=100Ω
Conditions
close as possible to the oscillator pins in order to
minimize output distortion and start-up stabiliza-
tion time. Refer to the crystal/ceramic resonator
manufacturer for more details (frequency, pack-
age, accuracy...).
LP oscillator
MP oscillator
MS oscillator
HS oscillator
Conditions
LP oscillator
MP oscillator
MS oscillator
HS oscillator
Min
>2
>4
>8
20
22
22
18
15
Typ
160
310
610
1
80
Max
Max
16
40
56
46
33
33
150
250
460
910
2
4
8
S
MHz
Unit
Unit
kΩ
pF
µA
value.