Low-Power Mobile VGA EMI Reduction IC
FCC approved method of EMI attenuation.
Generates a low EMI spread spectrum clock of the
Optimized for frequency range from:
o P1817A – 20 to 30MHz. Operation
o P1817B – 10 to 20MHz Operation
Internal loop filter minimizes external components
and board space.
Two selectable spread ranges.
Low inherent cycle-to-cycle jitter.
3.3V or 5V operating voltage range.
TTL or CMOS compatible outputs.
Ultra-low power CMOS design.
3.17mA @3.3V, 10MHz | 6.20mA@5.0V, 10MHz
4.28mA @3.3V, 14MHz | 7.50mA @5.0V, 14MHz
5.50mA @3.3V, 20MHz | 9.50mA @5.0V, 20MHz
Supports notebook VGA and other LCD timing
SSON pin for Spread Spectrum On/Off and
Standby Mode controls.
Available in 8-pin SOIC and TSSOP.
The P1817 is a versatile spread spectrum frequency
modulator designed specifically for input clock frequencies.
The P1817 reduces electromagnetic interference (EMI) at
the clock source, allowing system wide reduction of EMI of
down stream clock and data dependent signals. The P1817
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 P1817 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’.
The P1817 uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented in a proprietary all digital method.
The P1817 is targeted towards notebook VGA chip and
other displays using an LVDS interface, PC peripheral
devices, and embedded systems.
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.