November 2006
rev 1.3
Peak EMI Reducing Solution
Features
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•
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Generates an EMI optimized clock signal at
output.
Input frequency: 25MHz.
Frequency outputs:
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USB Clock (48MHz unmodulated)
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50MHz (modulated), ±1% centre spread
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•
•
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Modulation rate: 39KHz.
Spread Spectrum ON/OFF control
Supply voltage range 2.5V ± 5%.
Available in 8 Pin SOIC package.
Commercial and Industrial Temperature range.
ASM3P2853A
shielding that are required to pass EMI regulations. The
ASM3P2853A modulates the output of 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.
Applications
ASM3P2853A is targeted towards EMI management for
high speed digital applications such as PC peripheral
devices, consumer electronics and embedded controller
systems.
Product Description
The ASM3P2853A is a versatile spread spectrum
frequency
modulator.
The
ASM3P2853A
reduces
electromagnetic interference (EMI) at the clock source.
The ASM3P2853A allows significant system cost savings
by reducing the number of circuit board layers and
Block Diagram
V
DD
PWDNB
XIN
XOUT
Crystal
Oscillator
PLL1
USB Clock
(48MHz
Unmodulated)
SSONB
PLL2
50MHz
Modulated
V
SS
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 ]
