MC145159–1
6
MOTOROLA
CHARGE
Ramp Charge Indicator (PDIP, SOG – Pin 4, SSOP – Pin 9)
This output is high from the time fR goes high to the time
fV goes high (fR and fV are the frequencies at the phase
detector inputs). This high voltage indicates that the ramp
capacitor, CR, is being charged.
FSO
Three–State Frequency Steering Output (PDIP, SOG –
Pin 6, SSOP – Pin 11)
If the counted down input frequency on fin is higher than
the counted down reference frequency of OSCin, this output
goes low. If the counted down VCO frequency is lower than
that of the counted down OSCin, this output goes high.
The repetition rate of the frequency steering output pulses
is approximately equal to the difference of the frequencies
of the two counted down inputs from the VCO and OSCin.
See Application Note AN969 for further information.
LD
Lock Detector Indicator (PDIP, SOG – Pin 9, SSOP –
Pin 14)
This output is high during lock and goes low to indicate a
non–lock condition. The frequency and duration of the non–
lock pulses will be the same as either polarity of the fre-
quency steering output.
MC
Dual Modulus Prescaler Control (PDIP, SOG – Pin 8,
SSOP – Pin 13)
The modulus control level is low at the beginning of a
count cycle and remains low until the divide–by–A counter
has counted down from its programmed value. At that time,
the modulus control goes high and remains high until the di-
vide–by–N counter has counted the rest of the way down
from its programmed value (N – A additional counts since
both divide–by–N and divide–by–A are counting down during
the first portion of the cycle). Modulus control 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 of NT = N P + A, where P
and P + 1 represent the dual modulus prescaler divide values
respectively for high and low modulus control levels, N is the
number programmed into the divide–by–N counter, and A is
the number programmed into the divide–by–A counter.
SRout
Shift Register Output (PDIP, SOG – Pin 14, SSOP – Pin 19)
This pin is the non–inverted output of the last stage of the
32–bit serial data shift register. It is not latched by the ENB
line. If unused, SRout should be floated.
POWER SUPPLY
VDD
Positive Power Supply (PDIP, SOG – Pin 5, SSOP – Pin 10)
Positive power supply input for all sections of the device
except the analog phase detector. VDD and VDD
′
should be
powered up at the same time to avoid damage to the
MC145159–1. VDD must be tied to the same potential as
VDD
′
.
VSS
Negative Power Supply (PDIP, SOG – Pin 7, SSOP – Pin 12)
Circuit ground for all sections of the MC145159–1 except
the analog phase detector. VSS must be tied to the same po-
tential as VSS
′
.
VSS
′
Analog Phase Detector Circuit Ground (PDIP, SOG –
Pin 16, SSOP – Pin 1)
Separate power supply and ground inputs are provided to
help reduce the effects in the analog section of noise coming
from the digital sections of this device and the surrounding
circuitry.
VDD
′
Analog Power Supply (PDIP, SOG – Pin 19, SSOP – Pin 4)
Separate power supply and ground inputs are provided to
help reduce the effects in the analog section of noise coming
from the digital sections of this device and the surrounding
circuitry.