EMI Reduction IC
The ASM3P2183A is a versatile spread spectrum frequency
modulator designed specifically for a wide range of input clock
frequencies from 6 MHz to 90 MHz. (Refer to Input Frequency and
Modulation Rate Table). The ASM3P2183A can generate an EMI
reduced clock from an OSC or a system generated clock. The
ASM3P2183A offers a Down Spread clock with a percentage
deviation of −1.25% and a Center Spread clock with a percentage
deviation of ± 0.42%.
The ASM3P2183A reduces electromagnetic interference (EMI) at
the clock source, allowing system wide reduction of EMI of down
stream clock and data dependent signals. The ASM3P2183A 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 ASM3P2183A uses the most efficient and optimized
modulation profile approved by the FCC and is implemented in a
proprietary all digital method.
The ASM3P2183A 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 ASM3P2183A is targeted towards EMI management for
memory and LVDS interfaces in mobile graphic chipsets and
high−speed digital applications such as PC peripheral devices,
consumer electronics, and embedded controller systems.
• FCC Approved Method of EMI Attenuation
• Provides up to 15 dB EMI Reduction
• Generates a 1X Low EMI Spread Spectrum Clock of the Input
• Input Frequency Range: 6 MHz to 90 MHz
• Internal Loop Filter Minimizes External Components and Board
• Selectable Spread Options: Down and Center Spread
• 2 Spread Frequency Deviation Selections: −1.25% or ± 0.42%
• Low Inherent Cycle−to−Cycle Jitter
• Supply Voltage: 3.3 V ± 0.3 V
• Low Power CMOS Design
• Supports Notebook VGA and Other LCD Timing Controller
• Products are Available for Industrial Temperature Range
• Available in 8−pin SOIC and TSSOP Packages
• These are Pb−Free Devices
XIN / CLKIN
See detailed ordering and shipping information in the package
dimensions section on page 6 of this data sheet.
© Semiconductor Components Industries, LLC, 2011
August, 2011 − Rev. 3
Publication Order Number: