P2560B Datasheet, PDF (1/7 Pages) Alliance Semiconductor Corporation – Low Frequency EMI Reduction

November 2003
rev 1.0
P2560B
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 32
MHz
Internal loop filter minimizes external components
and board space
Two selectable spread ranges
Low inherent cycle-to-cycle jitter
3.3 V or 5 V operating voltage
CMOS/TTL compatible inputs and outputs
Ultra low power CMOS design: 5.50 mA @3.3 V
Supports notebook VGA and other LCD timing
controller applications
SSON pin for Spread Spectrum On/Off and
Standby Mode controls
Available in 8-pin SOIC and TSSOP
Product Description
The P2560B is a versatile spread spectrum frequency
modulator designed specifically for a wide range of clock
frequencies. It reduces electromagnetic interference
Block Diagram
(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 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
The P2560B is targeted toward the notebook VGA chip
and other displays using an LVDS interface, PC
peripheral devices, and embedded systems
Alliance Semiconductor
2575, Augustine Drive • Santa Clara, CA • Tel: [phone] • Fax: [phone] • www.alsc.com
Notice: The information in this document is subject to change without notice.