SM560

• 25 to 108 MHz Operating Frequency Range
• Wide (9) Range of Spread Selections
• Accepts Clock and Crystal Inputs
• Low Power Dissipation 3.3V = 85 mw. (50 MHz)
• Frequency Spread Disable Function
• Center Spread Modulation
• Low Cycle-to Cycle Jitter
• 8-pin SOIC package

The Cypress SM560 is a Spread Spectrum Clock Generator (SSCG) IC used for the purpose of reducing Electro Magnetic Interference (EMI) found in today's high-speed digital electronic systems.

The SM560 uses a Cypress proprietary Phase-Locked Loop (PLL) and Spread Spectrum Clock (SSC) technology to synthesize and frequency modulate the input frequency of the reference clock. By frequency modulating the clock, the measured EMI at the fundamental and harmonic frequencies of Clock (SSCLK1) is greatly reduced.

This reduction in radiated energy can significantly reduce the cost of complying with regulatory requirements and time to market without degrading the system performance.

The SM560 is a very simple and versatile device to use. The frequency and spread % range is selected by programming S0 and S1digital inputs. These inputs use three (3) logic states including High (H), Low (L) and Middle (M) logic levels to select one of the 9 available Frequency Modulation and Spread % ranges. Refer to Tables 2 and 3 for programming details.

The SM560 is optimized for SVGA (40 MHz) and XVGA (65MHz) Controller clocks and also suitable for the applications with the frequency range of 25 to 108 MHz.

A wide range of digitally selectable spread percentages is made possible by using Three-Level (High, Low and Middle) logic at the S0 and S1 digital control inputs.

The output spread (frequency modulation) is symmetrically centered on the input frequency. Spread Spectrum Clock Control (SSCC) function enables or disables the frequency spread and is provided for easy comparison of system performance during EMI testing.

The SM560 is available in an 8-pin SOIC package with a 0 to 70 operating temperature range.