P2560B Datasheet, PDF (1/8 Pages) Alliance Semiconductor Corporation – Low Frequency EMI Reduction

October 2006
rev 1.3
P2560B
Low Frequency EMI Reduction
Features
• FCC approved method of EMI attenuation
• Generates a low EMI spread spectrum and a non
spread reference signal of the input clock
frequency
• Optimized for input frequency range from
20 to 32MHz
• Internal loop filter minimizes external components
and board space
• Two selectable spread ranges
• 3.3V Operating Voltage
• Ultra low power CMOS design: 5.50 mA @3.3V
• Supports notebook VGA and other LCD timing
controller applications
• Available in 8-pin SOIC and TSSOP
circuit board layers and shielding traditionally required to
pass EMI regulations.
The P2560B 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 results 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 P2560B uses the most efficient and optimized
modulation profile approved by the FCC and is implemented
by using a proprietary all-digital method.
Applications
Product Description
The P2560B is a versatile spread spectrum frequency
modulator designed specifically for a wide range of clock
frequencies. It reduces electromagnetic interference (EMI) at
the clock source allowing system-wide reduction of EMI of
downstream clock and data dependent signals. It allows
significant system cost savings by reducing the number of
The P2560B is targeted toward the notebook VGA chip and
other displays using an LVDS interface, PC peripheral
devices and embedded systems.
Block Diagram
VDD
XIN /CLKIN
XOUT
Crystal
Oscillator
Frequency
Divider
Feedback
Divider
Modulation
Phase
Detector
Loop
Filter
PLL
VCO
Output
Divider
ModOUT
VSS
PulseCore Semiconductor Corporation
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.