mc145156 Lansdale Semiconductor, Inc., mc145156 Datasheet - Page 22

• Manufacturer Part Number: mc145156
• Description: Pll Frequency Synthesizer Family
• Manufacturer: Lansdale Semiconductor, Inc.

ML145158
OUTPUT PINS
PD out
Phase Detector A Output (Pin 5)
duces a loop–error signal that is used with a loop filter to con-
trol a VCO.
φR, φV
Phase Detector B Outputs (Pins 16, 15)
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 φ V pulsing low.
φ R remains essentially high.
lagging, then error information is provided by φ R pulsing low.
φ V remains essentially high.
φ V and φ R remain high except for a small minimum time peri-
od when both pulse low in phase.
MC
Dual–Modulus Prescaler 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 ÷ A counter has counted down from its
programmed value. At this time, MC goes high and remains
high until the ÷ N counter has counted the rest of the way
down from its programmed value (N – A additional counts
since both ÷ N and ÷ A are counting down during the first por-
tion of the cycle). MC is then set back low, the counters preset
to their respective programmed values, and the above sequence
repeated. This provides for a total programmable divide value
(N T ) = N • P + A where P and P + 1 represent the dual–modu-
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This single–ended (three–state) phase detector output pro-
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:
Double–ended phase detector outputs. These outputs can be
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
High–Impedance State
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ML145158
lus prescaler divide values respectively for high and low modu-
lus control levels, N the number programmed into the ÷ N
counter, and A the number programmed into the ÷ A counter.
Note that when a prescaler is needed, the dual–modulus ver-
sion offers a distinct advantage. The dual–modulus prescaler
allows a higher reference frequency at the phase detector input,
increasing system performance capability, 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 ÷ R and ÷ N
counter outputs respectively, allowing the counters to be 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 sys-
tem clock to a microprocessor controller.
POWER SUPPLY
V DD
Positive Power Supply (Pin 4)
from + 3 to + 9 V with respect to VSS.
V SS
Negative Power Supply (Pin 6)
ground.
Buffered, divided reference and fin 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-
LANSDALE Semiconductor, Inc.
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