P2008A Datasheet, PDF (1/8 Pages) Alliance Semiconductor Corporation – General Purpose EMI Reduction IC

November 2006
rev 1.4
P2008A
General Purpose EMI Reduction IC
Features
• FCC approved method of EMI attenuation.
• Provides up to 15dB of EMI suppression.
• Generates a 1X or ½ X low EMI spread
spectrum clock of the input frequency.
• Input frequency range: 4MHz to 32MHz.
• Internal loop filter minimizes external
components and board space.
• Spreading ranges from ±0.8% to ±3.2%.
• SSON# control pin for spread spectrum enable
and disable options.
• Low Cycle-to-Cycle jitter.
• 3.3V Operating Voltage.
• Ultra-low power CMOS design.
• Available in 8-pin SOIC and TSSOP Packages.
Product Description
The P2008A is a versatile spread spectrum frequency
modulator designed specifically for digital camera and
other digital video and imaging applications. The P2008A
reduces electromagnetic interference (EMI) at the clock
source, allowing system wide reduction of EMI of down
stream clock and data dependent signals. The P2008A
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 P2008A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all digital method.
The P2008A 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 results 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’.
Applications
The P2008A is targeted towards cable, xDSL, fax
modem, set-top box, USB controller, DSC, and other
embedded systems.
Block Diagram
SR0 SSON#
VDD
DIV2
XIN/CLKIN
XOUT
Crystal
Oscillator
Frequenc
y
Feedbac
k
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.