October 2003
rev E
P2027A
Alliance Semiconductor
2575, Augustine Drive
Santa Clara, CA
Tel: 408.855.4900
Fax: 408.855.4999
www.alsc.com
Notice: The information in this document is subject to change without notice.
General Purpose EMI Reduction IC
Features
FCC approved method of EMI attenuation
Provides up to 20 dB of EMI suppression
Generates a low EMI spread spectrum clock of
the input frequency
Optimized for 27 MHz operation
nternal
loop
filter
components and board space
3 selectable spread ranges and 2 modulation
rate options
SSON control pin for spread spectrum enable
and disable options
Low cycle-to-cycle jitter
3.3V operating voltage
16 mA output drives
TTL or CMOS compatible outputs
Low power CMOS design
Supports digital camera and other digital video
and imaging applications
Available in 8 pin SOIC and TSSOP
minimizes
external
Product Description
The P2027 is a versatile spread spectrum frequency
modulator designed specifically for digital camera
and other digital video and imaging applications. The
P2027 reduces electromagnetic interference (EMI) at
Block Diagram
the clock source, which provides system wide
reduction of EMI of all clock dependent signals. The
P2027 allows significant system cost savings by
reducing the number of circuit board layers and
shielding that are traditionally required to pass EMI
regulations.
The P2027 uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all-digital method.
The P2027 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 P2027 is targeted towards DSC market as well
as other imaging and digital video applications like
DVD and VCD players.