P2041A Datasheet, PDF (1/8 Pages) Alliance Semiconductor Corporation – Versatile EMI Reduction IC

November 2006
rev 0.2
P2041A
Versatile EMI Reduction IC
Features
ƒ FCC approved method of EMI attenuation
ƒ Provides up to 20dB of EMI suppression
ƒ Generates a low EMI spread spectrum clock of the
input frequency
ƒ Optimized for 25MHz to 60MHz input frequency
range
ƒ Internal loop filter minimizes external components
and board space
ƒ 4 selectable spread ranges
ƒ SSON control pin for spread spectrum enable and
disable options
ƒ Low Cycle-to-cycle jitter
ƒ 3.3V or 5.0V operating voltage
ƒ Low power CMOS design
ƒ Available in 8 pin SOIC and TSSOP Packages
Product Description
The P2041A is a selectable spread spectrum frequency
modulator designed specifically for PC peripheral and
embedded controller markets. The P2041A reduces
electromagnetic interference (EMI) at the clock source
which provides system wide reduction of EMI of all clock
dependent signals. The P2041A allows significant system
cost savings by reducing the number of circuit board layers
and shielding that are traditionally required to pass EMI
regulations.
The P2041A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all-digital method.
The P2041A 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 result 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 P2041A is targeted towards the embedded controller
market and PC peripheral markets including scanners,
MFP’s, printers, PDA, IA , and GPS devices.
Block Diagram
SR0 SR1 ^SSON
VDD
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.