ICST ICS7151AM-50T Spread spectrum clock generator Datasheet

ICS7151A-50
Spread Spectrum Clock Generator
Description
Features
The ICS7151A-50 is a clock generator for EMI
(Electromagnetic Interference) reduction. Spectral
peaks are attenuated by modulating the system clock
frequency. Down or center spread profiles are
selectable. Down spread will not exceed the maximum
frequency of an unspread clock, and center spread
does not change the average operating frequency of
the system
•
•
•
•
•
•
ICS offers many other clocks for computers and
computer peripherals. Consult ICS when you need to
remove crystals and oscillators from your board.
• Multiplication rate of x1/2
• Advanced, low-power CMOS process
• Pin compatible with the Fujitsu MB88151-500
Operating voltage of 3.3 V ±0.3 V
Packaged in 8-pin SOIC
Available in Pb (lead) free package
Input frequency range of 16.5 to 33.4 MHz
Output frequency ranges of 8.3 to 16.7 MHz
Provides a spread spectrum clock output (±0.5%,
±1.5% center spread; -1.0%, -3.0% down spread)
Block Diagram
VDD
S1:0
2
PLL Clock
Synthesis
and Spread
Spectrum
Circuitry
ENS
XIN
CKOUT
Clock Buffer/
Crystal
Ocsillator
XOUT
GND
External caps required with crystal for
accurate tuning of the clock
1
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
Pin Assignment
Spread Direction and Percentage
Select Table
XIN
1
8
XOUT
GND
2
7
S0
3
S1
4
VDD
S1
Pin 4
S0
Pin 3
Spread
Direction
Spread
Percentage (%)
6
ENS
0
0
Center
±1.5
5
CKOUT
0
1
Center
±0.5
1
0
Down
-1.0
1
1
Down
-3.0
8 pin (150 mil) SOIC
ENS
(note 1)
Modulation
0
No Modulation
1
Modulation
Notes:
1. Pin 1 has a pull-up resistor.
Pin Descriptions
Pin
Number
Pin
Name
Pin Type
1
XIN
Input
Crystal pin/clock input pin.
2
GND
Power
Connect to ground.
3
S0
Input
Select pin 0. Spread modulation select.
4
S1
Input
Select pin 1. Spread modulation select.
5
CKOUT
Output
6
ENS
Input
Modulation enable. Internal pull-up resistor.
7
VDD
Power
Connect to +3.3 V.
8
XOUT
Output
Crystal connection pin.
Clock output.
2
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
Pin Description
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
External Components
traces just underneath the device, or on layers adjacent
to the ground plane layer used by the device.
The ICS7151A-50 requires a minimum number of
external components for proper operation.
Crystal Information
A decoupling capacitor of 0.01µF must be connected
between GND and VDD on pins 2 and 7, as close to
these pins 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 50Ω trace (a commonly used
trace impedance) place a 27Ω resistor in series with
the clock line, as close to the clock output pin as
possible. The nominal impedance of the clock output is
25Ω.
PCB Layout Recommendations
For optimum device performance and lowest output
phase noise, the following guidelines should be
observed.
1) The 0.01µF decoupling capacitor should be mounted
on the component side of the board as close to the
VDD pin as possible. No vias should be used between
the decoupling capacitor and VDD pin. The PCB trace
to VDD pin should be kept as short as possible, as
should the PCB trace to the ground via.
2) To minimize EMI, the 27Ω series termination resistor
(if needed) should be placed close to the clock output.
The crystal used should be a fundamental mode (do
not use third overtone), 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) = (CL - 6) x 2
In the equation, CL 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 ICS7151A-50 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.
Modulation Rate
Frequency
Decoupling Capacitor
Time
3) 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 ICS7151A-50. This includes signal
3
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
Absolute Maximum Ratings
Stresses above the ratings listed below can cause permanent damage to the ICS7151A-50. 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.
Item
Rating
Supply Voltage, VDD
-0.5 to 4.0 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 (VIOVER)
VDD + 1.0 V (tOVER < 50 ns)
Undershoot (VIUNDER)
GND - 1.0 V (tUNDER < 50 ns)
Overshoot/Undershoot
tUNDER < 50 ns
VIOVER < VDD + 1.0 V
VDD
Input pin
GND
VIUNDER < GND - 1.0 V
tOVER < 50 ns
Recommended Operation Conditions
Parameter
Min.
Ambient Operating Temperature
-40
Power Supply Voltage (measured in respect to GND)
+3.0
3.3
Max.
Units
+85
°C
3.6
V
4
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
Typ.
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
DC Electrical Characteristics
Unless stated otherwise, VDD = 3.3 V ±0.3 V, Ambient Temperature -40 to +85°C
Parameter
Symbol
Operating Voltage
VDD
Supply Current
IDD
Conditions
Min.
Typ.
Max.
Units
3.0
3.3
3.6
V
10
14
mA
16.5
33.4
MHz
No load, at 3.3 V,
output = 24 MHz
Input Frequency
Input High Voltage
VIH
XIN, S0, S1, ENS
VDD * 0.8
VDD + 0.3
V
Input Low Voltage
VIL
XIN, S0, S1, ENS
0.0
VDD * 0.20
V
Output High Voltage
VOH
CKOUT, IOH = -4 mA
2.0
Output Low Voltage
VOL
CKOUT, IOL = 4 mA
0.4
V
Input Capacitance
CIN
XIN, S0, S1, ENS
16
pF
CKOUT, 8.3 to 66.7
MHz
15
pF
CKOUT, 66.7 to 100
MHz
10
pF
CKOUT, 100 to 133.4
MHz
7
pF
400
kΩ
Load Capacitance
CL
Input Pull-up Resistor
ENS
RPU
V
100
240
AC 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
Oscillation Frequency
fX
Fundamental
oscillation
16.5
33.4
MHz
Input Frequency
fIN
XIN
16.5
33.4
MHz
CKOUT, 2-frequency
division
8.3
16.7
MHz
XIN, 16.5 to 33.4 MHz
40
60
%
CKOUT, 1.5 V
40
60
%
CKOUT, 0.4 to 2.4 V,
load capacitance 15 pF
0.5
TBD
3.0
V/ns
TBD
200
ps
5
ms
Output Frequency
fOUT
Input Clock Duty Cycle
Output Clock Duty Cycle
tDCC
Output Slew Rate
50
Cycle to Cycle Jitter
tJC
No load, standard
deviation
Lock Time
tLK
CKOUT
2
CKOUT=TBD
33
Modulation Frequency
fMOD
5
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
kHz
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
Input Frequency (fIN = 1/tIN)
tIN
0.8 VDD
CKIN
Output Slew Rate
2.4 V
0.4 V
CKOUT
tr
tf
SR = (2.4 - 0.4) /tr, SR = (2.4 - 0.4) /tf
Thermal Characteristics
Parameter
Symbol
Thermal Resistance Junction to
Ambient
Thermal Resistance Junction to Case
Min.
Typ.
Max. Units
θJA
Still air
150
°C/W
θJA
1 m/s air flow
140
°C/W
θJA
3 m/s air flow
120
°C/W
40
°C/W
θJC
6
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
Conditions
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
Package Outline and Package Dimensions (8-pin SOIC, 150 Mil. Body)
Package dimensions are kept current with JEDEC Publication No. 95
Millimeters
8
Symbol
E
Min
A
A1
B
C
D
E
e
H
h
L
α
H
INDEX
AREA
1 2
D
Inches*
Max
Min
1.35
1.75
0.10
0.25
0.33
0.51
0.19
0.25
4.80
5.00
3.80
4.00
1.27 BASIC
5.80
6.20
0.25
0.50
0.40
1.27
0°
8°
Max
.0532
.0688
.0040
.0098
.013
.020
.0075
.0098
.1890
.1968
.1497
.1574
0.050 BASIC
.2284
.2440
.010
.020
.016
.050
0°
8°
*For reference only. Controlling dimensions in mm.
A
h x 45
A1
C
-Ce
SEATING
PLANE
B
L
.10 (.004)
C
Ordering Information
Part / Order Number
Marking
Shipping Packaging
Package
Temperature
ICS7151AM-50
ICS7151AM-50T
ICS7151AM-50LF
ICS7151AM-50LFT
ICS7151AMI-50
ICS7151AMI-50T
ICS7151AMI-50LF
ICS7151AMI-50LFT
7151AM50
7151AM50
151AM50L
151AM50L
151AMI50
151AMI50
51AMI50L
51AMI50L
Tubes
Tape and Reel
Tubes
Tape and Reel
Tubes
Tape and Reel
Tubes
Tape and Reel
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
8-pin SOIC
0 to +70° C
0 to +70° C
0 to +70° C
0 to +70° C
-40 to +85° C
-40 to +85° C
-40 to +85° C
-40 to +85° C
Parts that are ordered with a "LF" suffix to the part number are the Pb-Free configuration and are RoHS compliant.
While the information presented herein has been checked for both accuracy and reliability, Integrated Circuit Systems (ICS)
assumes no responsibility for either its use or for the infringement of any patents or other rights of third parties, which would
result from its use. No other circuits, patents, or licenses are implied. This product is intended for use in normal commercial
applications. Any other applications such as those requiring extended temperature range, high reliability, or other extraordinary
environmental requirements are not recommended without additional processing by ICS. ICS reserves the right to change any
circuitry or specifications without notice. ICS does not authorize or warrant any ICS product for use in life support devices or
critical medical instruments.
7
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
ICS7151A-50
Spread Spectrum Clock Generator
Revision History
Rev.
Originator
Date
A
J. Sarma
10/20/05
Description of Change
Rev A; new device/datasheet.
8
MDS 7151A-50 A
Integrated Circuit Systems, Inc.
●
525 Race Street, San Jose, CA 95126
Revision 102005
●
tel (408) 297-1201
●
www.icst.com
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