mc145220 Freescale Semiconductor, Inc, mc145220 Datasheet - Page 22

• Manufacturer Part Number: mc145220
• Description: Dual Frequency Synthesizer
• Manufacturer: Freescale Semiconductor, Inc

MC145220
22
NOTES:
OUTPUT
VCO
1. See the Phase–Locked Loop — Low–Pass Filter Design page for additional information.
2. For optimum performance, bypass the V+ and V+
3. The R counter is programmed for a divide value = REF in /f R . Typically, f R is the tuning resolution required for the VCO. Also, the
4. Pull–up voltage must be at the same potential as the V+ pin or less. Pull–up device other than a resistor may be used. (Pull–up
5. LD and LD are open–drain outputs. This allows the wired–OR configuration shown. Note that R1 and Q1 form the “pull–up device”.
6. Use of Q1 is optional and depends on loading.
Figure 23. Application Showing Use of Both the Single– and Double–Ended Phase/Frequency Detectors
VCO frequency divided by f R = N T = N
respectively. P is the lower divide ratio of the dual–modulus prescaler (i.e., 32 or 64).
device not required when Output A is configured as f R , f R , f V , f V , DATA OUT.)
BUFFER
LOW–PASS
FILTER
NOTE: See related Figures 25, 26, and 27.
CMOS
MCU
NOTE 4
GENERAL PURPOSE
DIGITAL OUTPUT
+V
D in
10
S
1
2
3
4
5
6
7
8
9
P + A; this determines the values (N, A) that must be programmed into the N and A counters,
Figure 24. Cascading Two Devices
CLK
REF in
REF out
LD
PD out / R
Rx/ V
GND
f in
f in
V+
OUTPUT A
(PORT)
DEVICE #1
i
ENB
pins to GND and GND
MC145220
(DATA OUT)
OUTPUT A
PD out / R
Rx
i
GND
NOTE 5
/ V
ENB
CLK
LD
V+
OPTIONAL
D in
f in
f in
i
i
i
i
i
i
i
with low–inductance capacitors.
R1
20
19
18
17
16
15
14
13
12
11
D in
Q1
+V
NOTE 6
CLK
DEVICE #2
+V
ENB
LOW–PASS
(DATA OUT)
OUTPUT A
FILTER
MCU
+V
BUFFER
MOTOROLA
OUTPUT
VCO