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Low EMI Spectrum Spread Clock
• Reduces Systemic EMI.
• Modulates external source clock.
• 3 - 5 Volt power supply.
• 14 to 120 MHz.operating frequency range.
• Output is multiplied or divided by 1, 2 or 4.
• Digitally controlled modulation.
• TTL/CMOS compatible outputs.
• Fout modulation centered around reference.
• Compliant with all major CISC, RISC and
• Low short term jitter.
• Synchronous output enable.
• Power down mode for low current operation.
• Available in 16 pin SOIC package.
• Desktop/Laptop Computer
• Scanners, Printers, Copiers, Fax Machines, MFP’s
• Disk and CD-ROM Drives
• Automotive and EmbeddedSystems
• Networking, LAN/WAN
• Digital Cameras, Games
• LCD displays
• Time to Market
• Lower cost of compliance
• Programmable EMI reduction
• No degradation in Rise/Fall times
• Lower component and PCB layer count
The IMI SM532 is a Spectrum Spread Clock Modulator designed for the purpose of reducing the Electro- Magnetic
Interference (EMI) found in today’s high speed digital systems. The SM532 is well suited for a wide range of digital
system applications that require a reduction of radiated energy. This unwanted radiated energy is usually found in
the odd harmonics of digital system clocks. By modulating the frequency of the digital clock, measured EMI at the
fundamental and harmonic frequencies is greatly reduced. This reduction in radiated energy can significantly
reduce the cost of complying with regulatory requirements and time to market, without degrading clock and timing
The IMI SM532 is extremely versatile and flexible in that program control is available for each of the operating
modes. Program control is provided for Input Frequency, Output Frequency Multiplication, Output Bandwidth,
Modulation ON/OFF and Fout state during Power Down Mode.
Depending on the range of operation, the output clock, Fout, can be a multiple (1, 2, 4) or a division (1, 1/2, 1/4) of
the input frequency. The power-down mode adds the flexibility of operating in a completely static mode for reduced
standby current and simplified system board testing.
There are many benefits to using the SM532 Low EMI Clock Modulator. The most important benefit is reducing
the amount of clock related EMI by as much as 12 - 18 dB, depending on the application. SM532 is available with
only Center-Spread frequency modulation. Refer to SM530 for Down-Spread frequency modulation and other
525 Los Coches St., Milpitas, 95035 408-263-6300, FAX 408-263-6571
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