ASM3P2812B

September 2003 ASM3P2811A/B ASM3P2812A/B ASM3P2814A/B rev 1.0 www.DataSheet4U.com Low Power EMI Reduction IC Features FCC approved method of EMI attenuation. Provides up to 15dB EMI reduction. Generates a 1X, 2X and 4X low EMI spread spectrum clock of the input frequency. o o o to 40 MHz. o o o ASM3P2811A/B: 10 to 40MHz ASM3P2812A/B: 10 to 40MHz ASM3P2814A/B: 10 to 40MHz 1X: ASM3P2811A/B 2X: ASM3P2812A/B 4X: ASM3P2814A/B deviation range from ±0.625% to –3.50%. The ASM3P28XX reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of down stream clock and data dependent signals. The ASM3P28XX 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 ASM3P28XX 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 ASM3P28XX uses the most efficient and optimized modulation profile approved by the FCC and is implemented in a proprietary all-digital method. Optimized for input frequency range from 10MHz Internal loop filter minimizes externa...