November 2006
rev 0.2
Spread Spectrum Selection
P2040B
Table 1 illustrates the possible spread spectrum options. The optimal setting should minimize system EMI to the fullest
without affecting system performance. The spreading is described as a percentage deviation of the center frequency (Note:
the center frequency is the frequency of the external reference input on CLKIN, Pin 1).
Example:
P2040B is designed for high resolution flat panel applications and is able to support panel frequencies from
30MHz to 100MHz. For a 65MHz pixel clock frequency, a spreading selection of CP0 = 0,CP1=1 and SR0=1 gives a
percentage deviation of +/-1.56% (see Table 1). This results in frequency on ModOUT being swept from 64.5MHz to
65.5MHz. This particular example given here is a common EMI reduction method for notebook LCD panel and has already
been implemented by most of the leading OEM and mobile graphic accelerator manufacturers.
Application Schematic for Mobile LCD Graphics Controllers
+3.3V
65MHz from Graphics
Modulation 65MHz signal
with +/- 1.56% Deviation
and Modulation Rate of
101.54 KHz. This signal is
connected back to the
Spread Spectrum input
Pin (SSIN) of the
Graphics Accelerator.
1
2
3
4
CLKIN
CP0
CP1
V
SS
V
DD
SR0
8
7
0.1 µF
ModOUT 6
SSON#
5
P2040B
Digital control for SS
enable or disable
Absolute Maximum Ratings
Symbol
V
DD
, V
IN
T
STG
T
A
T
s
T
J
T
DV
Storage temperature
Operating 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 +4.6
-65 to +125
-40 to +85
260
150
2
Unit
V
°C
°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.
LCD Panel EMI Reduction IC
Notice: The information in this document is subject to change without notice.
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