Spectrum Device
SSDCI1108AF
Spread Spectrum Clock Generator
SSDCI1108AF
■
DESCRIPTION
SSDCI1108AF 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.
SSDCI1108AF accepts an input clock either from a fundamental Crystal or from an external reference and locks on to it
delivering a 1x modulated clock output.
■
FEATURE
•
•
•
•
•
•
•
•
•
Power down pin :
50
PA
(Max) consumption current at power down
Input frequency : 12.0 MHz to
55.0
MHz
Output frequency : 12.0 MHz to
55.0
MHz (One-fold input frequency)
Analog
Spreading Range
Selection
Modulation clock output Duty :
45% to 55%
Modulation clock Cycle-Cycle Jitter : Less than
250
ps
Power supply voltage : 2.5V--3.3 V
Package : 8-pin TDFN
Operating temperature :
﹣
40
℃
to
﹢85 ℃
■
Application
SSDCI1108AF is targeted for consumer electronics
application such as MFP, STB, DSC, MID,HDMI,LCD panel
Camcorder,and other timing sensitive analog video imaging applications
Applications of HDMI, RJ45 port has good compatibility
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Spectrum Device
■
BLOCK DIAGRAM
V
DD
SSDCI1108AF
8
XIN / CKIN
1
Clock input
Clock out
CKOUT
2
Spread Spectrum
ON/OFF
SSON
3
Analog
Spreading
ADS 7
Range
setting
Modulation Rate
MR
6
Select
PLL block
Modulation
clock output
5
ModOUT
4
GND
1
−
M
Phase
compare
Charge
pump
V/I
conversion
Frequency setting
IDAC
ICO
Reference
clock
1
−
N
Modulation
clock output
Loop filter
1
−
L
Modulation logic
SSDCI1108AF PLL block
Modulation rate
setting/
Modulation enable
setting
A glitchless IDAC (current output D/A converter) provides precise modulation, thereby dramatically reducing
EMI.
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Spectrum Device
■
PIN ASSIGNMENT
TOP VIEW
SSDCI1108AF
XIN / CKIN
CKOUT
SSON
1
2
3
4
8 VDD
SSDCI1108AF
7 ADS
6
MR
5
ModOUT
GND
TDFN-8P
■
PIN DESCRIPTION
Pin name
XIN / CKIN
CKOUT
SSON
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)
Spread Spectrum ON/OFF. Spread Spectrum function enabled
when HIGH, disabled when LOW. Has an internal pull−up resistor.
GND
ModOUT
MR
GND pin
Modulation clock output
Modulation Rate Select. When LOW selects Low Modulation Rate.
Selects High Modulation Rate when pulled HIGH. Has an internal
pull−up resistor.
Spreading Range
Selection through external resistor to GND.
ADS
VDD
Power supply voltage pin
■
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
CHARACTERISTICS ”.
ADS modulation enable setting
Resistance(K ohm)
0-800K
Spreading Range(+/-%)
2.5 - 0.01
Note : Analog
Spreading Range
Selection through external resistor to GND.
Spectrum is spread (modulated) by centering on the input frequency.
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Spectrum Device
SSDCI1108AF
Spreading Range
vs ADS Resistance Chart
2.5
Spreading Range ( %)
2.0
1.5
1.0
0.5
0.0
2.5
Spreading Range ( %)
2.0
1.5
1.0
0.5
0.0
0
MR =0
MR
MR
=1
0
50
100
150
200
250
300
50 100 150 200 250 300 350 400 450 500 550 600 650
RESISTANCE (kW)
RESISTANCE (kW)
■
TYPICAL CRYSTAL SPECIFICATIONS
FUNDAMENTAL AT CUT PARALLEL RESONANT CRYSTAL
Nominal frequency
Frequency tolerance
Operating temperature range
Storage temperature
Load capacitance (CP)
Shunt capacitance
ESR
27 MHz
$50
ppm or better at 25°C
−25°C
to +85°C
−40°C
to +85°C
18 pF
7 pF maximum
25
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Spectrum Device
■
ABSOLUTE MAXIMUM RATINGS
Parameter
Power supply voltage*
Input voltage*
Output voltage*
Storage temperature
Operation junction
temperature
Output current
Junction Temperature
SSDCI1108AF
Symbol
V
DD
V
I
V
O
T
ST
T
J
I
O
Rating
Min
0.5
V
SS
0.5
V
SS
0.5
55
40
4
Max
4.0
V
DD
0.5
V
DD
0.5
125
85
8
Unit
V
V
V
qC
qC
mA
TJ
TDV
V
IOVER
V
IUNDER
V
SS
1.0 (t
UNDER
d
4ns)
150
1500
V
DD
1.0 (t
OVER
d
4 ns)
°C
V
V
V
Static Discharge Voltage
Overshoot
Undershoot
* : The parameter is based on VSS 0.0 V.
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
d4
ns
V
IOVER
d
V
DD
1.0 V
V
DD
Input pin
V
SS
t
OVER
d4
ns
V
IUNDER
d
V
SS
1.0 V
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stm32/stm8
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