P1819GF-08SR Datasheet, PDF (1/6 Pages) ON Semiconductor – Notebook LCD Panel EMI Reduction IC

P1819
Notebook LCD Panel EMI
Reduction IC
Features
• FCC approved method of EMI attenuation.
• Provides up to 15dB EMI reduction.
• Generates a low EMI Spread Spectrum clock and a
non-spread reference clock of the input frequency.
• Optimized for Frequency range from 20 to 40MHz.
• Internal loop filter minimizes external components
and board space.
• Selectable spread options: Down and Center.
• Low Inherent Cycle-to-Cycle jitter.
• Two different deviation selections.
• ModRate is compliant with ATI M7x VGA spec.
• 3.3V ± 0.3V Operating Voltage range.
• Low power CMOS design.
• Supports notebook VGA and other LCD timing
controller applications.
• Power Down function for mobile application.
• Available in 8-pin SOIC Package.
Product Description
The P1819 is a Versatile Spread Spectrum Frequency
Modulator designed specifically for input clock
frequencies from 20 to 40MHz. (Refer to Input Frequency
and Modulation Rate Table). The P1819 reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of down stream
clock and data dependent signals. The P1819 allows
significant system cost savings by reducing the number of
circuit board layers, ferrite beads, shielding, and other
passive components that are traditionally required to pass
EMI regulations.
The P1819 modulates the output of a single PLL in order
to “spread” the bandwidth of a synthesized clock, and
more importantly, decreases 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 frequency generators. Lowering EMI
by increasing a signal’s bandwidth is called ‘Spread
Spectrum Clock Generation’.
The P1819 is available in different spread deviation, refer
to Spread Deviation Selection Table.
The P1819 uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all digital method.
Applications
The P1819 is targeted towards EMI management for
memory and LVDS interfaces in mobile graphic chipsets
and high-speed digital applications such as PC peripheral
devices, consumer electronics, and embedded controller
systems.
Block Diagram
D_C/NC PD# SRS
VDD
XIN / CLKIN
XOUT
Crystal
Oscillator
REF
Frequency
Divider
Feedback
Divider
Modulation
Phase
Detector
©2010 SCILLC. All rights reserved.
NOVEMBER 2010 – Rev. 3.1
Loop
Filter
PLL
VCO
Output
Divider
ModOUT
VSS
Publication Order Number:
P1819/D