MC14046 Motorola, MC14046 Datasheet - Page 5

• Manufacturer Part Number: MC14046
• Description: Phase Locked Loop
• Manufacturer: Motorola

NOTE: Sometimes R3 is split into two series resistors each R3
Definitions: N = Total division ratio in feedback loop
MOTOROLA CMOS LOGIC DATA
PC1 out
VCO in
PCA in
PCB in
@ FREQUENCY f
C C should be such that the corner frequency of this network does not significantly affect n . In Figure B, the ratio of R3 to R4 sets the
damping, R4
(a)
INPUT
PCA in
K VCO
K = V DD / for Phase Comparator 1
K = V DD /4
for a typical design n
Phase Comparator 1
PCB in
+
R3
^
C2
2
V DD – 2 V
(0.1)(R3) for optimum results.
Note: for further information, see:
p D
14
(1) F. Gardner, “Phase–Lock Techniques”, John Wiley and Son, New York, 1966.
(2) G. S. Moschytz, “Miniature RC Filters Using Phase–Locked Loop”, BSTJ, May, 1965.
(3) Garth Nash, “Phase–Lock Loop Design Fundamentals”, AN–535, Motorola Inc.
(4) A. B. Przedpelski, “Phase–Locked Loop Design Articles”, AR254, reprinted by Motorola Inc.
3
for Phase Comparator 2
Figure 3. General Phase–Locked Loop Connections and Waveforms
2f C
f VCO
OUTPUT
COMPARATOR
[
PHASE
^
1
p
^
2
10
p
0.707
R3 C2
f r
2
p
(at phase detector input)
f L
2 OR 13
PC1 out
PC2 out
OR
V DD
V SS
V OH
V OL
V OH
V OL
V OH
V OL
Typical Low–Pass Filters
(a)
INPUT
LOW–PASS
EXTERNAL
EXTERNAL
COUNTER
FILTER
Waveforms
N
2. A capacitor C C is then placed from the midpoint to ground. The value for
VCO in
R3
R4
C2
9
R1
11
OUTPUT
w
z
F(s)
R2
9
n
+
PC2 out
VCO in
PCA in
PCB in
12
+
FOLLOWER
2K
+
SOURCE
LD
Filter A
VCO
f
R 3 C 2 S
N
K VCO
K
w
6
NR 3 C 2
CI A
f
n
K VCO
1
CI
Typically:
R 4 C 2
(R 3
)
f = f max – f min
LOW–PASS FILTER
Phase Comparator 2
10
7
)
1
CI B
3, 000
+
4
w
z
F(s)
n
+
f max
6N
+
R SF
W
0.5
+
) C 2
SF out
S(R 3 C 2
–
w
NC 2 (R 3
n (R 3 C 2
2
+
K
@ FREQUENCY Nf = f
p D
Filter B
R 3 C 2 S
N
f
100N
K VCO
f max 2
)
f
)
VCO out
R 4 C 2 )
)
D
MC14046B
R 4 )
)
f
K
1
– R 4 C 2
f
K VCO
)
N
V DD
V SS
V OH
V OL
V OH
V OL
V OH
V OL
V OH
V OL
1
5
)