ST72124J2 STMicroelectronics, ST72124J2 Datasheet - Page 120

• Manufacturer Part Number: ST72124J2
• Description: 8-BIT MCU WITH SINGLE VOLTAGE FLASH MEMORY,ADC, 16-BIT TIMERS, SPI, SCI INTERFACES
• Manufacturer: STMicroelectronics

Specifications of ST72124J2

• Clock Sources: crystal/ceramic resonator oscillators or RC oscillators, external clock, backup Clock Security System
• 4 Power Saving Modes: Halt, Active-Halt, Wait and Slow
• Two 16-bit Timers With: 2 input captures (only one on timer A), 2 output compares (only one on timer A), External clock input on timer A, PWM and Pulse generator modes

ST72334J/N, ST72314J/N, ST72124J
CLOCK CHARACTERISTICS (Cont’d)
16.5.4 RC Oscillators
The ST7 internal clock can be supplied with an RC
oscillator. This oscillator can be used with internal
Figure 70. Typical Application with RC oscillator
Figure 71. 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
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.
120/153
f
t
R
C
OSC
SU(OSC)
Symbol
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
3.2
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
R
EX
C
EX
-40°C
+25°C
ST72XXX
OSC1
OSC2
VDD [V]
Parameter
EX
is applied, the capacitance to be considered is the global parasitic capacitance which
+85°C
+125°C
4)
INTERNAL RC
1)
5.5
2)
3)
3)
EX
DD
see
R
R
R
R
see
and R
EX
EX
EX
EX
nominal at 5V, not tested in production.
=47K
=47K
=10K
=10K
Figure 71
Figure 72
EX
Conditions
Voltage generator
or external components (selectable by option
byte).
Figure 72. Typical External RC Oscillator
V
ranges taking into account the device process variation.
REF
fosc [MHz]
20
15
10
5
0
C
C
C
C
EX
EX
EX
EX
=”0”pF
=100pF
=6.8pF
=470pF
0
+
-
6.8
22
3.60
Min
V
0
10
1
DD
5)
Cex [pF]
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
discharge
5.10
470
14
47
270
f
OSC
MHz
Unit
K
470
ms
pF