November 2006
rev 1.1
Low Power 4X Multiplier EMI Reduction IC
Features
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ASM3P2274A
The ASM3P2274A uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented by using a proprietary all digital method.
The ASM3P2274A 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’.
Generates a 4X EMI optimized clock signal at the
output.
Integrated loop filter components.
Operates with a 3.3 / 2.5V Supply.
Low power CMOS design.
Input frequency range: 12MHz to 30MHz for 2.5V.
: 12MHz to 30MHz for 3.3V.
Frequency deviation: -1.5% (Typ) @66MHz
Output Frequency.
Available in 6-pin TSOT-23 Package.
Product Description
The ASM3P2274 is a versatile Spread Spectrum
Frequency Modulator designed specifically for a wide
range of clock frequencies. It provides a 4x Spread
Spectrum Modulated output from an input clock source.
The ASM3P2274A reduces electromagnetic interference
(EMI) at the clock source, allowing system wide reduction
of EMI of all clock dependent signals. The ASM3P2274A
allows significant system cost savings by reducing the
number of circuit board layers ferrite beads,
shielding
that are traditionally required to pass EMI regulations.
Applications
The ASM3P2274A is targeted towards all portable
devices with very low power requirements like MP3
players,MFP, LCD Panel Module and digital still cameras.
Key Specifications
Description
Supply voltages
Cycle-to-Cycle Jitter
Output Duty Cycle
Modulation Rate Equation
Frequency Deviation
Specification
VDD = 3.3V / 2.5V
360pS (Typ)
45/55%
F
IN
/640
-1.5% (Typ) @ 66MHz
Output
Block Diagram
VDD
PD
Modulation
XIN/CLKIN
XOUT
Crystal
Oscillator
Frequency
Divider
Feedback
Divider
Phase
Detector
Loop
Filter
PLL
VCO
Output
Divider
ModOUT
VSS
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 ]
