MC145151 Motorola, MC145151 Datasheet - Page 22

• Manufacturer Part Number: MC145151
• Description: Parallel-Input PLL Frequency Synthesizer
• Manufacturer: Motorola

OUTPUT PINS
PD out
Phase Detector A Output (Pin 5)
produces a loop–error signal that is used with a loop filter to
control a VCO.
Phase Detector B Outputs (Pins 16, 15)
be combined externally for a loop–error signal. A single–
ended output is also available for this purpose (see PD out ).
leading, then error information is provided by V pulsing low.
lagging, then error information is provided by R pulsing low.
period when both pulse low in phase.
MC
Dual–Modulus Prescale Control Output (Pin 12)
circuitry for controlling an external dual–modulus prescaler.
The MC level is low at the beginning of a count cycle and
remains low until the
programmed value. At this time, MC goes high and remains
high until the
down from its programmed value (N – A additional counts
since both N and
tion of the cycle). MC is then set back low, the counters pre-
set to their respective programmed values, and the above
sequence repeated. This provides for a total programmable
divide value (N T ) = N
MC145151–2 through MC145158–2
22
R , V
R remains essentially high.
V remains essentially high.
V and R remain high except for a small minimum time
This single–ended (three–state) phase detector output
Frequency f V > f R or f V Leading: Negative Pulses
Frequency f V < f R or f V Lagging: Positive Pulses
Frequency f V = f R and Phase Coincidence: High–Imped-
Double–ended phase detector outputs. These outputs can
If frequency f V is greater than f R or if the phase of f V is
If the frequency f V is less than f R or if the phase of f V is
If the frequency of f V = f R and both are in phase, then both
This output generates a signal by the on–chip control logic
ance State
N counter has counted the rest of the way
A are counting down during the first por-

P + A where P and P + 1 represent the
A counter has counted down from its
dual–modulus prescaler divide values respectively for high
and low modulus control levels, N the number programmed
into the
modulus version offers a distinct advantage. The dual–
modulus prescaler allows a higher reference frequency at
the phase detector input, increasing system performance ca-
pability, and simplifying the loop filter design.
f R , f V
R Counter Output, N Counter Output (Pins 13, 3)
f R and f V outputs are connected internally to the
used independently, as well as monitoring the phase detector
inputs.
LD
Lock Detector Output (Pin 7)
locked (f R , f V of same phase and frequency), and pulses low
when loop is out of lock.
REF out
Buffered Reference Oscillator Output (Pin 14)
ence oscillator to another frequency synthesizer, or as the
system clock to a microprocessor controller.
POWER SUPPLY
V DD
Positive Power Supply (Pin 4)
from + 3 to + 9 V with respect to V SS .
V SS
Negative Power Supply (Pin 6)
ground.
A counter. Note that when a prescaler is needed, the dual–
N counter outputs respectively, allowing the counters to be
Buffered, divided reference and f in frequency outputs. The
This output is essentially at a high level when the loop is
This output can be used as a second local oscillator, refer-
The positive power supply potential. This pin may range
The most negative supply potential. This pin is usually
N counter, and A the number programmed into the
MOTOROLA
R and