P1727 Datasheet, PDF (1/6 Pages) ETAL Group – PICK-OFF TRANSFORMER

P1727
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.
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 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.
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
CLKIN
Frequency
Divider
Feedback
Divider
Modulation
Phase
Detector
Loop
Filter
PLL
VCO
Output
Divider
ModOUT
REFOUT
VSS
©2010 SCILLC. All rights reserved.
JANUARY 2010 – Rev. 1
Publication Order Number:
P1727/D