st72321j STMicroelectronics, st72321j Datasheet - Page 147

• Manufacturer Part Number: st72321j
• Description: 8-bit Mcu With Nested Interrupts, Flash, 10-bit Adc, 5 Timers, Spi, Sci, I2c Interface
• Manufacturer: STMicroelectronics

CLOCK CHARACTERISTICS (Cont’d)
12.5.4 RC Oscillators
The ST7 internal clock can be supplied with an RC
oscillator. This oscillator can be used with internal
Figure 76. Typical Application with RC oscillator
Notes:
1. Data based on design simulation.
2. R
3. i
Figure 77. Typical f
f
f
R
C
|i
OSC (RCINT)
OSC(RCEXT)
CEX
EX
EX
EXTERNAL RC
CEX
Symbol
EX
4.5
3.5
2.5
1.5
0.5
|
4
3
2
1
0
must have a positive temperature coefficient (ppm/°C), carbon resistors should therefore not be used.
is the current needed to load the C
R
2.35
Internal RC oscillator frequency
See
External RC oscillator frequency
Oscillator external resistor
Oscillator external capacitor
Capacitor load current
EX
C
EX
Figure 77
OSC(RCINT)
ST72XXX
OSC1
OSC2
Parameter
V
DD
and
5
(V)
i
CEX
Figure 78
vs V
R
IN
3)
EX
INTERNAL RC
DD
2)
capacitor while OSC1 is forced to V
C
IN
TA=-45C
TA=25C
TA=130C
5.5
1)
T
OSC1 = V
A
=25°C, V
Conditions
Voltage generator
or external components (selectable by option
byte).
Figure 78. Typical f
V
REF
SS
DD
3.9
3.8
3.7
3.6
3.5
3.4
3.3
3.2
3.1
or 1.5V
4
3
=5V
-45
+
-
SS
0
or 1.5V (RC oscillation voltage range).
Min
56
22
2
OSC(RCINT)
V
DD
T
5 / (R
A
25
(°C)
Typ
3.5
290
EX
.C
Vdd = 2.4V
Vdd = 5V
vs T
EX
C
70
EX
Current copy
)
Max
discharge
A
100
470
350
5.6
ST72321J
f
130
147/179
OSC
MHz
Unit
K
pF
A