EMI Noise Reduction IC Spread Spectrum Clock Generator (SSCG) MB88150 Series FEATURES AND BENEFITS DESCRIPTION Electromagnetic interference (EMI) can effect the performance of a host of consumer, enterprise, communications and embedded equipment. As equipment becomes more sophisticated, utilizing a traditional approach to reducing EMI (such as shielding) can become less effective. The Spansion Spread Spectrum Clock Generator (SSCG) reduces EMI by dispersing the energy of the output clock. Spansion's proprietary technology digitally controls the clock frequency by making slight fluctuations to reduce the EMI noise. In the process, the SSCG can reduce the size of the final product, the development time and lower the overall cost. Significant reduction in EMI Spansion's complex frequency-modulation technology works out high effects of EMI noise and suppresses the main cause of that noise, peak clock frequency. Fewer EMI-prevention components The spread spectrum function can reduce the number of components needed, such as choke coils, shielding, ferrite or noise filters. The system board can be smaller since fewer components are needed. Faster development and lower costs By incorporating the SSCG in the initial development stages, it is possible to reduce the time and expense required for EMI evaluation, analysis, investigation, shield building and similar processes, speeding up development and lowering costs. CONVENTIONAL EMI MEASURES AND SSCG APPLICATION EXAMPLES Conventional measures against EMI have employed parts such as choke coils and shielded parts, as depicted in figure “A.” However, conventional measures are insufficient for many high-performance, multi-function devices. Spansion's SSCG, with its high anti-EMI effect, is being used more and more for these challenging applications. A. Conventional example EMI EMI ASIC CPU ASIC CPU Bus Capacitor As illustrated in figure “B,” the SSCG is inserted between the clock input (e.g., the ASIC or CPU) and the oscillation source (e.g., a crystal oscillator). B. SSCG application example Shielding parts Memory EMI SSCG Bus Ferrite bead choke coil Memory EMI EFFECTS OF SSCG: SPECTRUM WAVEFORM ON FUNDAMENTAL FREQUENCIES AND HARMONIC PEAKS Fundamental The SSCG can suppress both the clock-oscillation fundamental frequency and the harmonic peak. Peak reduction SSCG=OFF When utilizing the SSCG as the main ASIC CPU or similar function, the SSCG significantly reduces the EMI for the overall system. The SSCG does this by lowering both the signal output and the EMI noise from the ASIC or CPU. SSCG=ON Harmonic Peak reduction for harmonic as well SSCG=OFF Second Third SSCG=ON Fourth Second Third Fourth BLOCK DIAGRAM, MODULATED WAVEFORM AND SPECTRUM EVALUATION BOARD (EXAMPLE) Spansion’s digital approach, using a current D/A converter, achieves a suitable frequency modulation with a complex multi-cycle modulation waveform. 1/M VCO Reference clock Frequency phase comparator 1/N V-I conversion CP Loop Filter IDAC ICO Clock output Spansion original Digital control circuit Accurate modulated waveform Spectrum without peak Output clock cycle: T Modulated waveform of IDAC (measured waveform) Spectrum waveform Time: t SSCG PRODUCTS TABLE Product p/n Suffix 100 101 200 201 MB88151A 400 401 500 501 800 801 Multiplication ratio Part Number Input frequency (MHz) Output frequency range 2 16.6 1/2 100 110 120 160 33.4 33.2 66.8 66.4 133.6 8.3 8.3 16.7 16.7 66.4 101 MB88152A 80 16.6 33.4 4 111 Max. 40 Modulation rate (%) CLK output function Min. Max. Min. 1 8 Output frequency (MHz) 133.6 Total Modulation Power down REF CLK&REF Center OFF function output outputs ¬ ¬ (L output) ¬ ¬ (L output) ¬ ¬ (L output) ¬ ¬ (L output) ¬ ¬ (L output) 67 16.6 67 134 16.6 134 ¬ 134 40 134 ¬ 1 102 40 112 ¬ ¬ 1 101 110 1 16.6 134 16.6 134 (L output) ¬ 1 113 102 112 1 101 111 16.6 40 16.6 40 33 67 33 67 50 80 50 80 100 110 12.5 102 112 101 MB88155 ~1.5 ¬ ¬ ~-3.0 0.5 25 12.5 ¬ ¬ 1 ¬ ¬ (L outputs) ¬ 2 25 1 111 25 103 50 25 113 4 12.5 20 1 50 400 402 410 412 ~-3.0 1.5 111 103 MB88154A ¬ ¬ ¬ 50 80 2 ¬ ¬ ~-3.0 ~1.5 ¬ ¬ ~-2.0 ~1.0 ¬ ¬ ~-2.0 ~1.0 ¬ ¬ ~-2.0 ~1.0 ¬ ¬ ~-2.0 (L outputs) ¬ ¬ (L outputs) ~1.0 ~1.0 ¬ 8 SOP 3.0 3.6 8 SOP 3.0 3.6 8 SOP 3.0 3.6 8 SOP 3.0 3.6 8 TSSOP 3.0 3.6 Required external clock input of crystal resonator. ~-3.0 ~1.5 ¬ Min. Max. ¬ ¬ ¬ -3.0 ~-3.0 Type ¬ ¬ (L outputs) Remarks Nbr of pins -1.0 ~1.5 ¬ Power Supply (V) ~-3.0 ~1.5 ~1.5 100 MB88153A ~1.5 ~-3.0 ¬ 16.6 1 Down PKG ~1.0 ¬ ¬ ~-2.0 ~-2.0 ¬ ¬ "REF output pin" is generated from integrated crystal oscillation circuit. Spansion: 915 DeGuigne Drive, PO Box 3453, Sunnyvale, CA 94088-3453 USA +1 (408) 962-2500 | 1 866 SPANSION | www.spansion.com ©2014 Spansion®, the Spansion logo, MirrorBit®, MirrorBit® Eclipse™, Easy DesignSim™, Traveo™ and combinations thereof, are trademarks and registered trademarks of Spansion LLC in the United States and other countries. Other names used are for informational purposes only and may be trademarks of their respective owners. www.facebook.com/spansion AD409-00001-1v0-E, July 2014 twitter: @spansion www.youtube.com/spansioninc www.linkedin.com/company/spansion