CLOCK 11
1
f
2.3R
C
tc tc
if 1 kHz ≤ f ≤ 100 kHz
and 2R < R < 10R
tc
RESET
10 OUT 1
9
OUT 2
tc
S
(f in Hz, R in ohms, C in farads)
R
tc
The formula may vary for other frequencies. Recommended
maximum value for the resistors in 1 MΩ.
R
C
tc
S
Figure 3. Oscillator Circuit Using RC Configuration
TYPICAL RC OSCILLATOR CHARACTERISTICS
100
8.0
4.0
V
= 10 V
DD
50
V
= 15 V
DD
f AS A FUNCTION
20
10
5
OF R
TC
(C = 1000 pF)
(R 2R
0
≈
)
TC
S
1.0 V
–4.0
–8.0
f AS A FUNCTION
OF C
2
1
(R
= 56 k
Ω)
TC
5.0 V
(R = 120 k)
S
0.5
–12
–16
0.2
0.1
R
= 56 k
Ω
R
R
= 0, f = 10.15 kHz @ V
= 10, T = 25°C
TC
C = 1000 pF
S
S
DD A
= 120 kΩ, f = 7.8 kHz @ V
= 10 V, T = 25°C
DD A
1.0 k
10 k
100 k
1.0 M
0.1
–55
–25
0
25
50
75
C)
100
125
R
, RESISTANCE (OHMS)
TC
0.001
C, CAPACITANCE (
T , AMBIENT TEMPERATURE (
°
A
0.0001
0.01
F)
µ
Figure 4. RC Oscillator Stability
Figure 5. RC Oscillator Frequency as a
Function of R
and C
TC
CLOCK
11
500 kHz 32 kHz
Circuit Circuit
Characteristic
Unit
Crystal Characteristics
Resonant Frequency
Equivalent Resistance, R
RESET
10 OUT 1
9
OUT 2
500
1.0
32
6.2
kHz
kΩ
S
18M
External Resistor/Capacitor Values
R
O
R
C
C
47
82
20
750
82
20
kΩ
pF
pF
O
T
S
C
C
T
S
Frequency Stability
Frequency Changes as a Function
Figure 6. Typical Crystal Oscillator Circuit
of V
(T = 25 C)
A
DD
DD
DD
V
V
Change from 5.0 V to 10V
Change from 10 V to 15 V
+ 6.0
+ 2.0
+ 2.0
+ 2.0
ppm
ppm
Frequency Change as a Function
of Temperature (V = 10 V)
DD
Change from – 55 Cto
+25 C Complete Oscillator*
Change from + 25 C to
+ 100
– 160
+ 120
– 560
ppm
ppm
T
A
T
A
+125 C Complete Oscillator*
* Complete oscillator includes crystal, capacitors, and resistors.
Figure 7. Typical Data for Crystal Oscillatgor Circuit
MC14060B
MOTOROLA CMOS LOGIC DATA
4