ASM3P2274A Datasheet, PDF (1/7 Pages) PulseCore Semiconductor – Low Power 4X Multiplier EMI Reduction IC

ASM3P2274A
4X Multiplier
EMI Reduction IC
Features
• Generates a 4X EMI optimized clock signal at the
output.
• Integrated loop filter components.
• Operates with a 3.3 / 2.5V Supply.
• 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 6L-TSOP (6L-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 and shielding
that are traditionally required to pass EMI regulations.
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.’
Applications
The ASM3P2274A is targeted towards all portable
devices 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%
FIN/640
-1.5% (Typ) @ 66MHz
Output
Block Diagram
VDD
PD
XIN / CLKIN
XOUT
Crystal
Oscillator
Frequency
Divider
Feedback
Divider
Modulation
Phase
Detector
Loop
Filter
PLL
VCO
Output
Divider
ModOUT
VSS
©2010 SCILLC. All rights reserved.
JANUARY 2010 – Rev. 2
Publication Order Number:
ASM3P2274/D