P2005A Datasheet, PDF (1/8 Pages) Alliance Semiconductor Corporation – Low Frequency EMI Reduction IC

November 2006
rev 1.3
P2005A/S
Low Frequency EMI Reduction IC
Features
• FCC approved method of EMI attenuation.
• Provides up to 15dB of EMI suppression.
• Generates a 1X or ½X low EMI spread spectrum
clock of the input frequency.
• Input frequency range: 8MHz to 32MHz.
• Internal loop filter minimizes external
components and board space.
• Frequency deviation:
• P2005A: ± 1% to ± 3%
• P2005S: ± 0.6% to ± 1.8%
• SSON# control pin for spread spectrum enable
and disable options.
• Low cycle-to-cycle jitter.
• 3.3V or 5V operating voltage range.
• Ultra-low power CMOS design.
• Available in 8-pin SOIC and TSSOP.
Product Description
The P2005A/S is a versatile spread spectrum frequency
modulator designed specifically for input clock
frequencies from 8MHz to 32MHz. Refer Output
Frequency Selection Table. The P2005A/S can generate
an EMI reduced clock from crystal, ceramic resonator, or
system clock. The P2005A/S offers various percentage
BlockDiagram
SR0 SSON#
deviations ranging form ±0.6% to ±3.0%. Refer
Frequency Deviation Selections Table. The P2005A/S
reduces electromagnetic interference (EMI) at the clock
source, allowing system wide reduction of EMI of down
stream clock and data dependent signals. The P2005A/S
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 P2005A/S uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all digital method.
The P2005A/S 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 P2005A/S is targeted towards EMI management for
high-speed digital applications such as PC peripheral
devices, consumer electronics and embedded controller
systems.
VDD
DIV2
XIN
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.