LM565/LM565C
Phase Locked Loop
General Description
The LM565 and LM565C are general purpose phase locked
loops containing a stable, highly linear voltage controlled os-
cillator for low distortion FM demodulation, and a double bal-
anced phase detector with good carrier suppression. The
VCO frequency is set with an external resistor and capacitor,
and a tuning range of 10:1 can be obtained with the same
capacitor. The characteristics of the closed loop
systembandwidth, response speed, capture and pull in
rangemay be adjusted over a wide range with an external
resistor and capacitor. The loop may be broken between the
VCO and the phase detector for insertion of a digital fre-
quency divider to obtain frequency multiplication.
The LM565H is specified for operation over the −55˚C to
+125˚C military temperature range. The LM565CN is speci-
fied for operation over the 0˚C to +70˚C temperature range.
Features
n200 ppm/˚C frequency stability of the VCO
nPower supply range of ±5to±
12 volts with 100 ppm/%
typical
n0.2%linearity of demodulated output
nLinear triangle wave with in phase zero crossings
available
nTTL and DTL compatible phase detector input and
square wave output
nAdjustable hold in range from ±1%to >±60%
Applications
nData and tape synchronization
nModems
nFSK demodulation
nFM demodulation
nFrequency synthesizer
nTone decoding
nFrequency multiplication and division
nSCA demodulators
nTelemetry receivers
nSignal regeneration
nCoherent demodulators
Connection Diagrams
Metal Can Package
DS007853-2
Order Number LM565H
See NS Package Number H10C
Dual-in-Line Package
DS007853-3
Order Number LM565CN
See NS Package Number N14A
May 1999
LM565/LM565C Phase Locked Loop
© 1999 National Semiconductor Corporation DS007853 www.national.com
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage ±12V
Power Dissipation (Note 2) 1400 mW
Differential Input Voltage ±1V
Operating Temperature Range
LM565H −55˚C to +125˚C
LM565CN 0˚C to +70˚C
Storage Temperature Range −65˚C to +150˚C
Lead Temperature
(Soldering, 10 sec.) 260˚C
Electrical Characteristics
AC Test Circuit, T
A
=25˚C, V
CC
=±6V
Parameter Conditions LM565 LM565C Units
Min Typ Max Min Typ Max
Power Supply Current 8.0 12.5 8.0 12.5 mA
Input Impedance (Pins 2, 3) −4V <V
2
,V
3
<0V 7 10 5 k
VCO Maximum Operating
Frequency C
o
=2.7 pF 300 500 250 500 kHz
VCO Free-Running Frequency C
o
=1.5 nF
R
o
=20 k
f
o
=10 kHz −10 0 +10 −30 0 +30 %
Operating Frequency
Temperature Coefficient −100 −200 ppm/˚C
Frequency Drift with
Supply Voltage 0.1 1.0 0.2 1.5 %/V
Triangle Wave Output Voltage 2 2.4 3 2 2.4 3 V
p-p
Triangle Wave Output Linearity 0.2 0.5 %
Square Wave Output Level 4.7 5.4 4.7 5.4 V
p-p
Output Impedance (Pin 4) 5 5 k
Square Wave Duty Cycle 45 50 55 40 50 60 %
Square Wave Rise Time 20 20 ns
Square Wave Fall Time 50 50 ns
Output Current Sink (Pin 4) 0.6 1 0.6 1 mA
VCO Sensitivity f
o
=10 kHz 6600 6600 Hz/V
Demodulated Output Voltage
(Pin 7) ±10%Frequency Deviation 250 300 400 200 300 450 mV
p-p
Total Harmonic Distortion ±10%Frequency Deviation 0.2 0.75 0.2 1.5 %
Output Impedance (Pin 7) 3.5 3.5 k
DC Level (Pin 7) 4.25 4.5 4.75 4.0 4.5 5.0 V
Output Offset Voltage
|V
7
−V
6
|30 100 50 200 mV
Temperature Drift of |V
7
−V
6
| 500 500 µV/˚C
AM Rejection 30 40 40 dB
Phase Detector Sensitivity K
D
0.68 0.68 V/radian
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is func-
tional, but do not guarantee specific performance limits. Electrical Characteristics state DC andAC electrical specifications under particular test conditions which guar-
antee specific performance limits. This assumes that the device is within the Operating Ratings. Specifications are not guaranteed for parameters where no limit is
given, however, the typical value is a good indication of device performance.
Note 2: The maximum junction temperature of the LM565 and LM565C is +150˚C. For operation at elevated temperatures, devices in the TO-5 package must be
derated based on a thermal resistance of +150˚C/W junction to ambient or +45˚C/W junction to case. Thermal resistance of the dual-in-line package is +85˚C/W.
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Typical Performance Characteristics
Power Supply Current as a
Function of Supply Voltage
DS007853-14
Lock Range as a Function
of Input Voltage
DS007853-15
VCO Frequency
DS007853-16
Oscillator Output
Waveforms
DS007853-17
Phase Shift vs Frequency
DS007853-18
VCO Frequency as a
Function of Temperature
DS007853-19
Loop Gain vs Load
Resistance
DS007853-20
Hold in Range as a
Function of R
6–7
DS007853-21
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Schematic Diagram
DS007853-1
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AC Test Circuit
Typical Applications
DS007853-5
Note: S1open for output offset voltage (V7−V
6
) measurement.
2400 Hz Synchronous AM Demodulator
DS007853-6
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Typical Applications (Continued)
FSK Demodulator (2025–2225 cps)
DS007853-7
FSK Demodulator with DC Restoration
DS007853-8
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Typical Applications (Continued)
Frequency Multiplier (x10)
DS007853-9
IRIG Channel 13 Demodulator
DS007853-10
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Applications Information
In designing with phase locked loops such as the LM565, the
important parameters of interest are:
FREE RUNNING FREQUENCY
LOOP GAIN: relates the amount of phase change between
the input signal and the VCO signal for a shift in input signal
frequency (assuming the loop remains in lock). In servo
theory, this is called the “velocity error coefficient.”
The loop gain of the LM565 is dependent on supply voltage,
and may be found from:
f
o
=VCO frequency in Hz
V
c
=total supply voltage to circuit
Loop gain may be reduced by connecting a resistor between
pins 6 and 7; this reduces the load impedance on the output
amplifier and hence the loop gain.
HOLD IN RANGE: the range of frequencies that the loop will
remain in lock after initially being locked.
f
o
=free running frequency of VCO
V
c
=total supply voltage to the circuit
THE LOOP FILTER
In almost all applications, it will be desirable to filter the sig-
nal at the output of the phase detector (pin 7); this filter may
take one of two forms:
A simple lag filter may be used for wide closed loop band-
width applications such as modulation following where the
frequency deviation of the carrier is fairly high (greater than
10%), or where wideband modulating signals must be fol-
lowed.
The natural bandwidth of the closed loop response may be
found from:
Associated with this is a damping factor:
For narrow band applications where a narrow noise band-
width is desired, such as applications involving tracking a
slowly varying carrier, a lead lag filter should be used. In gen-
eral, if 1/R
1
C
1
<K
o
K
D
, the damping factor for the loop be-
comes quite small resulting in large overshoot and possible
instability in the transient response of the loop. In this case,
the natural frequency of the loop may be found from
R
2
is selected to produce a desired damping factor δ, usually
between 0.5 and 1.0. The damping factor is found from the
approximation: δ)πτ
2
f
n
These two equations are plotted for convenience.
Simple Lead Filter
DS007853-11
Lag-Lead Filter
DS007853-12
Filter Time Constant vs Natural Frequency
DS007853-13
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Applications Information (Continued) Capacitor C
2
should be much smaller than C
1
since its func-
tion is to provide filtering of carrier. In general C
2
0.1 C
1
.
Damping Time Constant vs Natural Frequency
DS007853-14
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Physical Dimensions inches (millimeters) unless otherwise noted
Metal Can Package (H)
Order Number LM565H
NS Package Number H10C
Dual-In-Line Package (N)
Order Number LM565CN
NS Package Number N14A
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Notes
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accordance with instructions for use provided in the
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significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
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LM565/LM565C Phase Locked Loop
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.