X2040C-08TR
| Model | X2040C-08TR |
| Description | LCD Panel EMI Reduction IC |
| PDF file | Total 9 pages (File size: 160K) |
| Chip Manufacturer | ALSC |
September 2005
rev 1.4
Spread Spectrum Selection
P2040C
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:
P2040C is designed for high resolution flat panel applications and is able to support panel frequencies from 50MHz
to 170MHz. For a 65MHz pixel clock frequency, a spreading selection of MRA=0, SR1=1 and SR0 =1 provides a percentage
deviation of ±1.50% (see Table 1). This result in frequency on ModOUT being swept from 64.03MHz to 65.98MHz at a
modulation rate of 50.77KHz (see Table 1). This particular example (see Figure below) 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
`
65MHz from graphics accelerator
1
CLKIN
MRA
SR1
VDD
8
SR0
7
ModOUT
SSON#
6
2
0.1µF
Modulated 65MHz signal with
±1.5 % deviation and modulation
rate of 50.77KHz. This signal is
connected back to the spread
+3.3V
spectrum input pin (SSIN) of the
graphics accelerator.
3
4 VSS
5
P2040C
Digital control for the SS enable
or disable
LCD Panel EMI Reduction IC
Notice: The information in this document is subject to change without notice.
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