P1727 Datasheet, PDF (1/9 Pages) ETAL Group – PICK-OFF TRANSFORMER

April 2007
rev 0.2
Features
Low Power Notebook LCD Panel EMI Reduction IC
P1727
• 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)
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
PulseCore Semiconductor
1715 S. Bascom Ave Suite 200, Campbell, CA 95008 • Tel: [phone] • Fax: [phone]
www.pulsecoresemi.com
Notice: The information in this document is subject to change without notice.