February 2008
rev 1.2
Peak Reducing EMI Solution
Features
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ASM3P2180A
clock and data dependent signals. ASM3P2180A allows
significant system cost savings by reducing the number
of circuit board layers, and shielding that are traditionally
required
to
pass
EMI
regulations.
ASM3P2180A
modulates the output of a single PLL in order to
“spread” the bandwidth of a synthesized clock, thereby
decreasing 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 clock generators. Lowering EMI by increasing
a signal’s bandwidth is called spread spectrum clock
generation. ASM3P2180A uses the most efficient and
optimized modulation profile approved by the FCC and
is implemented by using a proprietary all-digital method.
Generates a 1x EMI optimized clock output.
Input frequency: 6MHz - 10MHz
18MHz - 30MHz
Output frequency: 6MHz - 10MHz
18MHz - 30MHz
Two selectable down spread options.
Selectable frequency range.
Integrated loop filter components.
Operates with a 3.3V supply.
Low-power CMOS design.
Commercial temperature range
8-pin SOIC and 8-pin TSSOP packages
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Product Description
The ASM3P2180A is a versatile spread spectrum
frequency modulator designed specifically for a wide
range of clock frequencies. ASM3P2180A reduces
electromagnetic interference (EMI) at the clock source,
allowing system wide reduction of EMI of down stream
Applications
The ASM3P2180A is targeted towards notebook LCD
displays, other displays using an LVDS interface, PC
peripheral devices and embedded systems.
Block Diagram
VDD
SS%
FS
CLKIN / XIN
XOUT
Crystal
Oscillator
Modulation
CLKOUT
PLL
GND
PulseCore Semiconductor Corporation
1715 S. Bascom Ave Suite 200, Campbell, CA 95008
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Tel: 408-879-9077
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Fax: 408-879-9018
www.pulsecoresemi.com
Notice: The information in this document is subject to change without notice.
PULSECORE [ PulseCore Semiconductor ]
