Motorola CMOS Logic Manual page 342

V DD
V DD
PULSE
IN 2
GENERATOR
R
V SS
V DD
R o
V DD
18 M
IN 1
IN 2
C S C T
R
V SS
* Optional for low power operation,
10 kΩ R 70 kΩ.
Figure 3. Crystal Oscillator Circuit
MC14521B
6–304
V DD
Q18
Q19
C L
Q20
C L
Q21
C L
Q22
C L
Q23
C L
Q24
C L
V SS
Figure 2. Switching Time Test Circuit and Waveforms
Crystal Characteristics
Resonant Frequency
Equivalent Resistance, R S
External Resistor/Capacitor Values
R o
C T
R*
C S
V DD
Frequency Stability
Frequency Change as a Function
OUT 1
of V DD (T A = 25 _ C)
OUT 2
Q18 V DD Change from 5.0 V to 10 V
Q19
V DD Change from 10 V to 15 V
Q20
Frequency Change as a Function
Q21
of Temperature (V DD = 10 V)
Q22
T A Change from – 55 _ C to + 25 _ C
Q23
Q24
V SS
T A Change from + 25 _ C to + 125 _ C
R*
*Complete oscillator includes crystal, capacitors, and resistors.
Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î
Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î Î
20 ns
IN 2
C L
10%
t WL
50%
Q n
Characteristic
MC14521 only
Complete Oscillator*
MC14521 only
Complete Oscillator*
Figure 4. Typical Data for Crystal Oscillator Circuit
MOTOROLA CMOS LOGIC DATA
20 ns 20 ns
90%
50%
t WH
90%
10%
t PLH t PHL
t TLH t THL
500 kHz 50 kHz
Circuit Circuit
Unit
500 50 kHz
1.0 6.2
47 750
82 82
20 20
+ 6.0 + 2.0 ppm
+ 2.0 + 2.0 ppm
– 4.0 – 2.0 ppm
+ 100 + 120 ppm
– 2.0 – 2.0 ppm
– 160 – 560 ppm
kΩ
kΩ
pF
pF