Spectrum Device
SSDCI1107AF
Spread Spectrum Clock Generator
SSDCI1107AF
■
DESCRIPTION
SSDCI1107AF is a clock generator for EMI (Electro Magnetic Interference) reduction. The peak of unnecessary (EMI)
can be attenuated by making the oscillation frequency slightly modulate periodically with the internal modulator.
SSDCI1107AF accepts an input clock either from a fundamental Crystal or from an external reference (AC or DC
coupledto XIN/CLKIN) and locks on to it delivering a 1x modulated clock output.
■
FEATURE
•
•
•
•
•
•
•
•
•
Power down pin : 4
PA
(Typ-sample) consumption current at power down
Input frequency : 10.0 MHz to 94.0 MHz
Output frequency : 10.0 MHz to 94.0 MHz (One-fold input frequency)
Analog
Spreading Range
Selection
Modulation clock output Duty : 40 to 60
Modulation clock Cycle-Cycle Jitter : Less than 50 ps
Power supply voltage : 2.5V--3.3 V
Package : 8-pin TDFN
Operating temperature :
40
qC
to
85 qC
■
Application
Applications including USB and SATA.
Can be usde for EMI reduction such as
GPS,LCD
panel Etc.
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Spectrum Device
■
BLOCK DIAGRAM
V
DD
SSDCI1107AF
8
XIN / CKIN
1
Clock input
Clock out
Frequency setting
CKOUT
2
FREQ0
3
PLL block
Modulation
clock output
5 ModCK OUT
Analog
Spreading
ADS 7
Range
setting
FREQ1 6
Frequency setting
4
GND
1
−
M
Phase
compare
Charge
pump
V/I
conversion
Frequency setting
IDAC
ICO
Reference
clock
1
−
N
Modulation
clock output
Loop filter
Modulation rate
setting/
Modulation enable
setting
1
−
L
Modulation logic
SSDCI1107AF PLL block
A glitchless IDAC (current output D/A converter) provides precise modulation, thereby dramatically reducing
EMI.
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Spectrum Device
SSDCI1107AF
■
PIN ASSIGNMENT
TOP VIEW
XIN / CKIN
CKOUT
FREQ0
GND
1
2
3
4
8 VDD
SSDCI1107AF
7 ADS
6 FREQ1
5 ModCK OUT
TDFN-8P
■
PIN DESCRIPTION
Pin name
XIN / CKIN
CKOUT
FREQ0
GND
ModCK OUT
FREQ1
ADS
VDD
I/O
I
I
I
---
O
I
I
---
Pin no.
1
2
3
4
5
6
7
8
Description
Clock input pin (or External reference clock input).
Crystal connection( external reference, this pin should be left open)
Frequency setting pin
GND
pin
Modulation clock output
Frequency setting pin
Spreading Range
Selection through external resistor to
GND.
Power supply voltage pin
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Spectrum Device
SSDCI1107AF
■
PIN SETTING
When changing the pin setting, the stabilization wait time for the modulation clock required. The stabilization
wait time for the modulation clock takes the maximum value of Lock-Up time in “■ ELECTRICAL CHARACTER-
ISTICS
x
AC Characteristics”.
ADS modulation enable setting
Resistance(K ohm)
0-500K
---
Note : Analog
Spreading Range
Selection through external resistor to
GND.
Spectrum is spread (modulated) by centering on the input frequency.
Spreading Range(+/-%)
3.5 - 0.01
---
FREQ0, FREQ1 frequency setting
FREQ0
FREQ1
L
L
H
H
H
L
H
L
Input frequency range
10 MHz to 30 MHz
20 MHz to 54 MHz
60 MHz to 94 MHz
40 MHz to 60 MHz
Note : It is set according to the frequency of the clock input to the device. Set FREQ0 pin to “H” for the pin opened
because FREQ0 pin has pull-up resistor.
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Spectrum Device
■
ABSOLUTE MAXIMUM RATINGS
Parameter
Power supply voltage*
Input voltage*
Output voltage*
Storage temperature
Operation junction
temperature
Output current
Overshoot
Undershoot
Symbol
V
DD
V
I
V
O
T
ST
T
J
I
O
V
IOVER
V
IUNDER
0.0 V.
Rating
Min
0.5
V
SS
0.5
V
SS
0.5
55
40
2
V
SS
1.0 (t
UNDER
d
4 ns)
Max
4.0
V
DD
0.5
V
DD
0.5
125
85
4.5
SSDCI1107AF
Unit
V
V
V
qC
qC
mA
V
V
V
DD
1.0 (t
OVER
d
4 sn)
* : The parameter is based on V
SS
WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current,
temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings.
Overshoot/Undershoot
t
UNDER
d
4 ns
V
IOVER
d
V
DD
1.0 V
V
DD
Input pin
V
SS
t
OVER
d
4 ns
V
IUNDER
d
V
SS
1.0 V
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PCB设计
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