April 2007
rev 0.2
Low Power Notebook LCD Panel EMI Reduction IC
Features
•
FCC approved method of EMI attenuation
•
Generates a low EMI spread spectrum of
the input clock frequency
•
Optimized for frequency range:
P1727X: 20MHz to 40MHz
•
Internal loop filter minimizes external
components and board space
•
8 different frequency deviations ranging
from +/-0.625% to –3.50%
•
Low inherent Cycle-to-cycle jitter
•
3.3V Operating Voltage
•
Supports notebook VGA and other LCD
timing controller applications
•
Available in 8 pin SOIC and TSSOP
•
Qualified for Industrial Temp Spec.
(-40°C to +85°C)
P1727
significant system cost savings by reducing the number
of circuit board layers and shielding that are traditionally
required to pass EMI regulations.
The P1727 modulates the output of a single PLL in
order to “spread” the bandwidth of a synthesized clock,
thereby
decreasing
the
peak
amplitudes
of
its
harmonics. This result in significantly lower system EMI
compared to the typical narrow band signal produced
by oscillators and most clock generators. Lowering EMI
by increasing a signal’s bandwidth is called “spread
spectrum clock generation”.
The P1727 uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented by using a proprietary all-digital method.
Product Description
The P1727 is a versatile spread spectrum
frequency modulator designed specifically for a wide
range of clock frequencies. The P1727 reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of down stream
(clock and data dependent signals). The P1727 allows
Applications
The P1727 is targeted towards notebook LCD displays,
other displays using an LVDS interface, PC peripheral
devices and embedded systems.
Block Diagram
PDB
VDD
Modulation
CLKIN
Frequency
Divider
Feedback
Divider
PLL
Phase
Detector
Loop
Filter
VCO
Output
Divider
ModOUT
REFOUT
VSS
PulseCore Semiconductor
1715 S. Bascom Ave Suite 200, Campbell, CA 95008
•
Tel: 408-879-9077
•
Fax: 408-879-9018
www.pulsecoresemi.com
Notice: The information in this document is subject to change without notice.
April 2007
rev 0.2
Pin Configuration
CLKIN
VDD
VSS
1
2
3
8
7
6
5
PDB
NC
NC
REFOUT
P1727
P1727
ModOUT 4
Table 1 – Power Down Selection
PDB
0
1
Spread Spectrum
N/A
ON
ModOUT
Disabled
Normal
PLL
Disabled
Normal
Mode
Power Down
Normal
Table 2 Frequency Deviation Selection
P/ N
P1727A
P1727B
P1727C
P1727D
Deviation
-1.25%
-1.75%
-2.50%
-3.50%
P/N
P1727E
P1727F
P1727G
P1727H
Deviation
+/-0.625%
+/-0.875%
+/-1.25%
+/-1.75%
Pin Description
Pin#
1
2
3
4
5
6
7
8
Pin Name
CLKIN
VDD
VSS
ModOUT
REFOUT
NC
NC
PDB
Type
I
P
P
O
O
Description
External reference frequency input. Connect to externally generated
reference signal.
Connect to +3.3V
Ground Connection. Connect to system ground.
Spread Spectrum Clock output
Reference output.
No connect
No connect
I
Powerdown Pin.Pull low to disable spread spectrum clock output.
Low Power Notebook LCD Panel EMI Reduction IC
Notice: The information in this document is subject to change without notice.
2 of 9
April 2007
rev 0.2
Schematic for notebook VGA application
P1727
27MHz Pixel Clock input
VDD
0.1 µF
1
2
3
CLKIN
VDD
VSS
ModOUT
PDB 8
NC 7
NC 6
REFOUT 5
Tie low to enable
Powerdown mode.
P1727
ModOut Clock
4
Reference Clock O/P
Absolute Maximum Ratings
Symbol
VDD, V
IN
T
STG
T
s
T
J
T
DV
Storage temperature
Max. Soldering Temperature (10 sec)
Junction Temperature
Static Discharge Voltage
(As per JEDEC STD22- A114-B)
Parameter
Voltage on any pin with respect to Ground
Rating
-0.5 to +7
-65 to +125
260
150
2
Unit
V
°C
°C
°C
KV
Note: These are stress ratings only and are not implied for functional use. Exposure to absolute maximum ratings for prolonged periods of time may affect
device reliability.
Low Power Notebook LCD Panel EMI Reduction IC
Notice: The information in this document is subject to change without notice.
3 of 9
April 2007
rev 0.2
DC Electrical Characteristics
Symbol
V
IL
V
IH
I
IL
I
IH
V
OL
V
OH
I
DD
I
CC
V
DD
t
ON
Z
OUT
T
A
Input Low voltage
Input High voltage
Input Low current
Input High current
Output Low current
Output High current
VDD = 3.3V, I
OL
= 20mA
VDD = 3.3V, I
OH
= 20mA
2.5
2
14
3.0
3.3
0.18
50
0
70
18
3.6
P1727
Parameter
Min
VSS – 0.3
2.0
Typ
Max
0.8
VDD +0.3
-35
35
0.4
Unit
V
V
µA
µA
V
V
mA
mA
V
mS
Ω
°C
Static Supply Current (CLKIN, PDB pulled Low)
Dynamic Supply Current (No Load)
Operating Voltage
Power up time (first locked clock cycle after power up)
Clock Output impedance
Operating temperature
AC Electrical Characteristics
Symbol
f
IN
f
OUT
t
LH1
t
HL
1
Parameter
Input Frequency:
Output Frequency
Output Rise time
Output Fall time
Jitter (Cycle to cycle)
Output Duty cycle
P1727X
P1727X
Measured from 0.8V to 2.0V
Measured from 2.0V to 0.8V
Min
20
20
0.7
0.6
45
Typ
Max
40
40
Unit
MHz
MHz
nS
nS
pS
%
0.9
0.8
225
50
1.1
1.0
325
55
t
JC
t
D
Note: 1. t
LH
and t
HL
are measured with a capacitive load of 15pF
Low Power Notebook LCD Panel EMI Reduction IC
Notice: The information in this document is subject to change without notice.
4 of 9
Embedded System
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