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Электронный компонент: 7152M12L

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ICS7152
MDS 7152 E
1
Revision 012306
Integrated Circuit Systems, Inc.
525 Race Street, San Jose, CA 95126
tel (408) 297-1201
www.icst.com
Spread Spectrum Clock Generator
Description
The ICS7152-01, -02, -11, and -12 are clock
generators for EMI (Electro Magnetic Interference)
reduction (see below for frequency ranges and
multiplier ratios). Spectral peaks can be attenuated by
slightly modulating the oscillation frequency. Both down
and center spread profiles are selectable. Center
spread maintains an average frequency equal to an
unspread clock. Down spread meets maximum
frequency specs over the entire modualtion cycle.
Features
Operating voltage of 3.3 V 0.3 V
Packaged in 8-pin SOIC
Input frequency range of 16.6 to 134.0 MHz
Output frequency range of 16.6 to 134.0 MHz
Provides a spread spectrum clock output (0.5%,
1.5% center spread; -1.0%, -3.0% down spread)
Advanced, low-power CMOS process
Industrial temperature range available
Available in Pb (lead) free package
Block Diagram
Product Lineup
Product
Input Frequency Range
Modulation Type
Modulation Enable Pin
ICS7152M-01, ICS7152MI-01
16.6 MHz to 67 MHz
Down spread
Yes
ICS7152M-02, ICS7152MI-02
40.0 MHz to 134.0 MHz
ICS7152M-11, ICS7152MI-11
16.6 MHz to 67.0 MHz
Center spread
ICS7152M-12, ICS7152MI-12
40.0 MHz to 134.0 MHz
PLL Clock
Synthesis
and Spread
Spectrum
Circuitry
SEL
FREQ
CKOUT
GND
VDD
Clock Buffer/
Crystal
Ocsillator
XIN
XOUT
External caps required with crystal for
accurate tuning of the clock
XENS
Spread Spectrum Clock Generator
MDS 7152 E
2
Revision 012306
Integrated Circuit Systems, Inc.
525 Race Street, San Jose, CA 95126
tel (408) 297-1201
www.icst.com
ICS7152
Pin Assignment
Modulation Enable Setting Table
SEL Modulation Rate Setting Table
Frequency Setting Table
Pin Descriptions
XENS
Pin 8
Spread Spectrum
0
ON
1
OFF
XENS
XOUT
GND
FREQ
SEL
CKOUT
VDD
XIN
1
2
3
4
8
7
6
5
8 pin (150 mil) SOIC
SEL
Pin 4
(note1)
Spread
Direction
Spread
Percentage (%)
Part Number
0
Center
0.5
ICS7152M-11,
ICS7152M-12
Down
-1.0
ICS7152M-01,
ICS7152M-02
1
Center
1.5
ICS7152M-11,
ICS7152M-12
Down
-3.0
ICS7152M-01,
ICS7152M-02
FREQ
Pin 7
Frequency
0
16.6 to 40 MHz
ICS7152M-01,
ICS7152M-11
40 to 80 MHz
ICS7152M-02,
ICS7152M-12
1
33 to 67 MHz
ICS7152M-01,
ICS7152M-11
66 to 134 MHz
ICS7152M-02,
ICS7152M-12
Pin
Number
Pin
Name
Pin Type
Pin Description
1
XIN
Input
Crystal resonator connection pin/clock input pin.
2
XOUT
Output
Crystal resonator connection pin.
3
GND
Power
Connect to ground.
4
SEL
Input
Modulation rate setting pin.
5
CKOUT
Output
Modulated clock output pin.
6
VDD
Power
Connect to +3.3 V.
7
FREQ
Input
Frequency setting pin.
8
XENS
Output
Modulation enable setting pin.
Spread Spectrum Clock Generator
MDS 7152 E
3
Revision 012306
Integrated Circuit Systems, Inc.
525 Race Street, San Jose, CA 95126
tel (408) 297-1201
www.icst.com
ICS7152
External Components
The ICS7152 requires a minimum number of external
components for proper operation.
Decoupling Capacitor
A decoupling capacitor of 0.01F must be connected
between GND and VDD on pin 6, as close to this pin as
possible. For optimum device performance, the
decoupling capacitor should be mounted on the
component side of the PCB. Avoid the use of vias in the
decoupling circuit.
Series Termination Resistor
Series termination should be used on the clock output.
To series terminate a 50
trace (a commonly used
trace impedance) place a 27
resistor in series with
the clock line, as close to the clock output pin as
possible. The nominal impedance of the clock output is
25
.
PCB Layout Recommendations
For optimum device performance and lowest output
phase noise, the following guidelines should be
observed.
1) An optimum layout is one with all components on the
same side of the board, minimizing vias through other
signal layers. Other signal traces should be routed
away from the ICS7152. This includes signal traces just
underneath the device, or on layers adjacent to the
ground plane layer used by the device.
Crystal Information
The crystal used should be a fundamental mode,
parallel resonant. Crystal capacitors should be
connected from pins X1 to ground and X2 to ground to
optimize the initial accuracy. The value of these
capacitors is given by the following equation:
Crystal caps (pF) = (C
L
- 6) x 2
In the equation, C
L
is the crystal load capacitance. So,
for a crystal with a 16 pF load capacitance, two 20 pF
[(16-6) x 2] capacitors should be used.
Spread Spectrum Profile
The ICS7152 low EMI clock generator uses a triangular
frequency modulation profile for optimal down stream
tracking of zero delay buffers and other PLL devices.
The frequency modulation amplitude is constant with
variations of the input frequency.
Time
Fr
eq
ue
ncy
Modulation Rate
Spread Spectrum Clock Generator
MDS 7152 E
4
Revision 012306
Integrated Circuit Systems, Inc.
525 Race Street, San Jose, CA 95126
tel (408) 297-1201
www.icst.com
ICS7152
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS7152. These ratings,
which are standard values for ICS commercially rated parts, are stress ratings only. Functional operation of
the device at these or any other conditions above those indicated in the operational sections of the
specifications is not implied. Exposure to absolute maximum rating conditions for extended periods can
affect product reliability. Electrical parameters are guaranteed only over the recommended operating
temperature range.
Overshoot/Undershoot
Recommended Operation Conditions
Item
Rating
Supply Voltage, VDD
7 V
All Inputs and Outputs (referenced to GND)
-0.5 V to VDD+0.5 V
Ambient Operating Temperature
-40 to +85
C
Storage Temperature
-55 to +125
C
Junction Temperature
-40 to +125
C
Soldering Temperature
260
C
Overshoot (V
IOVER
)
VDD + 1.0 V (t
OVER
< 50 ns) max
Undershoot (V
IUNDER
)
GND - 1.0 V (t
UNDER
< 50 ns) min
Parameter
Min.
Typ.
Max.
Units
Ambient Operating Temperature
-40
+85
C
Power Supply Voltage (measured in respect to GND)
+3.0
3.3
3.6
V
Input pin
V
IOVER
< V
DD
+ 1.0 V
V
IUNDER
< GND - 1.0 V
t
OVER
< 50 ns
t
UNDER
< 50 ns
V
DD
GND
Spread Spectrum Clock Generator
MDS 7152 E
5
Revision 012306
Integrated Circuit Systems, Inc.
525 Race Street, San Jose, CA 95126
tel (408) 297-1201
www.icst.com
ICS7152
DC Electrical Characteristics
Unless stated otherwise, VDD = 3.3 V 0.3 V, Ambient Temperature -40 to +85
C
Parameter
Symbol
Conditions
Min.
Typ.
Max.
Units
Operating Voltage
VDD
3.0
3.3
3.6
V
Supply Current
IDD
No load, at 3.3 V
14
28
mA
Input High Voltage
V
IH
SEL, FREQ, XENS
VDD x 0.8
VDD + 0.3
V
XIN, Input slew rate
3 V/ns, 16.6 to 100
MHz
VDD x 0.8
VDD + 0.3
V
XIN, Input slew rate
3 V/ns, 100 to 134
MHz
VDD x 0.9
VDD + 0.3
V
Input Low Voltage
V
IL
SEL, FREQ, XENS
GND
VDD x 0.20
V
XIN, Input slew rate
3 V/ns, 16.6 to 100
MHz
GND
VDD x 0.20
V
XIN, Input slew rate
3 V/ns, 100 to 134
MHz
GND
VDD x 0.10
V
Output High Voltage
V
OH
CKOUT, I
OH
= -4 mA
VDD - 0.5
VDD
V
Output Low Voltage
V
OL
CKOUT, I
OL
= 4 mA
GND
0.4
V
Input Capacitance
C
IN
XIN, SEL, XENS
16
pF
Load Capacitance
C
L
CKOUT, 16.6 to 67
MHz
15
pF
CKOUT, 67 to 100
MHz
10
pF
CKOUT, 100 to 134
MHz
7
pF
Output Impedance
Z
O
CKOUT, 16.6 to 134
MHz
25