mc145201dt Freescale Semiconductor, Inc, mc145201dt Datasheet - Page 9

• Manufacturer Part Number: mc145201dt
• Description: 2.0 Ghz Pll Frequency Synthesizers
• Manufacturer: Freescale Semiconductor, Inc

f V . This signal is the buffered output of the 12–stage N
counter. The f V signal appears as normally low and pulses
high, and can be used to verify the operation of the prescaler,
A counter, and N counter. The divide ratio between the f in in-
put and the f V signal is N
N counter and A is the divide ratio of the A counter. These
ratios are determined by bits loaded into the A register. See
Figure 16. The maximum frequency at which the phase
detectors operate is 2 MHz. Therefore, the frequency of f V
should not exceed 2 MHz.
Data Out. This signal is the serial output of the 24–1/2–stage
shift register. The bit stream is shifted out on the high–to–low
transition of the CLK input. Upon power up, OUTPUT A is
automatically configured as Data Out to facilitate cascading
devices.
signal is a general–purpose digital output which may be used
as an MCU port expander. This signal is low when the Port
bit (C1) of the C register is low, and high when the Port bit is
high.
OUTPUT B
Open–Drain Digital Output (Pin 15)
be used as an MCU port expander. This signal is low when
the Out B bit (C0) of the C register is low. When the Out B bit
is high, OUTPUT B assumes the high–impedance state.
OUTPUT B may be pulled up through an external resistor or
active circuitry to any voltage less than or equal to the poten-
tial of the V PD pin. Note: the maximum voltage allowed on
the V PD pin is 9.5 V for the MC145200 and 5.5 V for the
MC145201.
PUT B to a low level.
REFERENCE PINS
REF in and REF out
Reference Input and Reference Output (Pins 20 and 1)
This pair of pins can be configured in one of two modes: the
crystal mode or the reference mode. Bits R13, R14, and R15
in the R register control the modes as shown in Figure 17.
when connected to terminals of an external parallel–reso-
nant crystal. Frequency–setting capacitors of appropriate
values as recommended by the crystal supplier are con-
nected from each of the two pins to ground (up to a maximum
of 30 pF each, including stray capacitance). An external re-
sistor of 1 M to 15 M is connected directly across the pins
to ensure linear operation of the amplifier. The device is de-
signed to operate with crystals up to 15 MHz; the required
connections are shown in Figure 8. To turn on the oscillator,
bits R15, R14, and R13 must have an octal value of one (001
in binary, respectively). This is the active–crystal mode
shown in Figure 17. In this mode, the crystal oscillator runs
and the R Counter divides the crystal frequency, unless the
part is in standby. If the part is placed in standby via the C
register, the oscillator runs, but the R counter is stopped.
However, if bits R15 to R13 have a value of 0, the oscillator is
stopped, which saves additional power. This is the shut–
MOTOROLA
If A23 = high and A22 = low, OUTPUT A is configured as
If A23 = low and A22 = high, OUTPUT A is configured as
If A23 = A22 = low, OUTPUT A is configured as Port. This
This signal is a general–purpose digital output which may
Upon power–up, power–on reset circuitry forces OUT-
Configurable pins for a Crystal or an External Reference.
In crystal mode, these pins form a reference oscillator
64 + A. N is the divide ratio of the
down crystal mode (shown in Figure 17) and can be engaged
whether in standby or not.
to 27 MHz from an external reference oscillator, such as a
TCXO. A signal swinging from at least the V IL to V IH levels
listed in the Electrical Characteristics table may be directly
coupled to the pin. If the signal is less than this level, ac cou-
pling must be used as shown in Figure 8. Due to an on–
board resistor which is engaged in the reference modes, an
external biasing resistor tied between REF in and REF out is
not required.
the output of a divider. As an example, if bits R15, R14, and
R13 have an octal value of seven, the frequency at REF out is
the REF in frequency divided by 16. In addition, Figure 17
shows how to obtain ratios of eight, four, and two. A ratio of
one–to–one can be obtained with an octal value of three.
Upon power up, a ratio of eight is automatically initialized.
The maximum frequency capability of the REF out pin is
10 MHz. Therefore, for REF in frequencies above 10 MHz,
the one–to–one ratio may not be used. Likewise, for REF in
frequencies above 20 MHz, the ratio must be more than two.
for R15, R14, and R13 and the REF out pin should be floated.
A value of two allows REF in to be functional while disabling
REF out , which minimizes dynamic power consumption and
electromagnetic interference (EMI).
LOOP PINS
f in and f in
Frequency Inputs (Pins 11 and 10)
feed the on–board RF amplifier which drives the 64/65 pres-
caler. These inputs may be fed differentially. However, they
usually are used in a single–ended configuration (shown in
Figure 7). Note that f in is driven while f in must be tied to
ground via a capacitor.
f in because this configuration is not tested for sensitivity. The
sensitivity is dependent on the frequency as shown in the
Loop Specifications table.
PD out
Single–Ended Phase/Freq. Detector Output (Pin 6)
a loop error signal when combined with an external low–pass
filter. The phase/frequency detector is characterized by a lin-
ear transfer function (no dead zone). The operation of the
phase/ frequency detector is described below and is shown
in Figure 18.
In the reference mode, REF in (Pin 20) accepts a signal up
With the reference mode, the REF out pin is configured as
If REF out is unused, an octal value of two should be used
These pins are frequency inputs from the VCO. These pins
Motorola does not recommend driving f in while terminating
This is a three–state current–source/sink output for use as
POL bit (C7) in the C register = low (see Figure 15)
Frequency of f V > f R or Phase of f V Leading f R : current–
Frequency of f V < f R or Phase of f V Lagging f R : current–
Frequency and Phase of f V = f R : essentially a floating
POL bit (C7) = high
Frequency of f V > f R or Phase of f V Leading f R : current–
Frequency of f V < f R or Phase of f V Lagging f R : current–
sinking pulses from a floating state
sourcing pulses from a floating state
state; voltage at pin determined by loop filter
sourcing pulses from a floating state
sinking pulses from a floating state
MC145200 MC145201
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