ST72C334J4TAE STMicroelectronics, ST72C334J4TAE Datasheet - Page 121

• Manufacturer Part Number: ST72C334J4TAE
• Description: 8-bit MCU for automotive with single voltage Flash/ROM memory, ADC, 16-bit timers, SPI, SCI interfaces
• Manufacturer: STMicroelectronics

CLOCK CHARACTERISTICS (Cont’d)
15.5.4 RC Oscillators
The ST7 internal clock can be supplied with an RC
oscillator. This oscillator can be used with internal
Figure 69. Typical Application with RC oscillator
Figure 70. Typical Internal RC Oscillator
Notes:
1. Data based on characterization results.
2. Guaranteed frequency range with the specified C
Data based on design simulation.
3. Data based on characterization results done with V
4. R
5. Important: When no external C
which is subject to high variation (package, application...). In this case, the RC oscillator frequency tuning has to be done
by trying out several resistor values.
f
t
R
C
Symbol
OSC
SU(OSC)
EX
EX
EXTERNAL RC
EX
must have a positive temperature coefficient (ppm/°C), carbon resistors should therefore not be used.
fosc [MHz]
4.3
4.2
3.9
3.8
4.1
4
Internal RC oscillator frequency
External RC oscillator frequency
Internal RC Oscillator Start-up Time
External RC Oscillator Start-up Time
Oscillator external resistor
Oscillator external capacitor
3.2
R
EX
C
EX
-40°C
+25°C
ST72XXX
OSC1
OSC2
Parameter
VDD [V]
EX
+85°C
+125°C
is applied, the capacitance to be considered is the global parasitic capacitance
4)
INTERNAL RC
1)
2)
5.5
ST72334xx-Auto, ST72314xx-Auto, ST72124Jx-Auto
3)
3)
EX
see
R
R
R
R
see
DD
and R
EX
EX
EX
EX
nominal at 5V, not tested in production.
Figure 70
Figure 71
= 47KΩ, C
= 47KΩ, C
= 10KΩ, C
= 10KΩ, C
EX
Conditions
Voltage generator
or external components (selectable by option
byte).
Figure 71. Typical External RC Oscillator
V
ranges taking into account the device process variation.
fosc [MHz]
20
15
10
REF
5
0
EX
EX
EX
EX
0
= “0”pF
= 100pF
= 6.8pF
= 470pF
+
-
6.8
22
3.60
Min
0
V
10
1
DD
Cex [pF]
5)
47
Typ
2.0
1.0
6.5
0.7
3.0
100
C
EX
Current copy
Rex=10KOhm
Rex=15KOhm
Rex=22KOhm
Rex=33KOhm
Rex=39KOhm
Rex=47KOhm
Max
5.10
discharge
470
14
47
270
f
121/150
OSC
MHz
Unit
470
KΩ
ms
pF