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ASM3P2814B Dataheets PDF



Part Number ASM3P2814B
Manufacturers Alliance Semiconductor Corporation
Logo Alliance Semiconductor Corporation
Description (ASM3P281xA/B) Low Power EMI Reduction IC
Datasheet ASM3P2814B DatasheetASM3P2814B Datasheet (PDF)

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 electroma.

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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 external components and board space. Selectable spread options: Down Spread and Center Spread. 8 spread frequency deviation selections: o ±0.625% to –3.5% Low inherent cycle-to-cycle jitter. 3.3V operating voltage range. CMOS/TTL compatible inputs and outputs. Pinout compatible with Cypress CY25811, CY25812 and CY25814. Products are available for industrial temperature range. Available in 8-pin SOIC and TSSOP. Applications The ASM3P28XX 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. Product Description The ASM3P28XX devices are versatile spread spectrum frequency modulators designed specifically for a wide range of input clock frequencies from 10MHz to 40MHz. (Refer Input/Output Frequency Range Selection Table). The ASM3P28XX can generate an EMI reduced clock from crystal, ceramic resonator, or system clock. The of spread options and percentage ASM3P28XX-A and the ASM3P28XX-B offer various combinations deviations (Refer Output Frequency Deviation and Spread Option Selection Table). These combinations include Down and Center Spread and percentage Alliance Semiconductor 2575, Augustine Drive • Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com Notice: The information in this document is subject to change without notice. September 2003 ASM3P2811A/B ASM3P2812A/B ASM3P2814A/B www.DataSheet4U.com rev 1.0 Block Diagram D_C SRS FRS VDD Modulation XIN Crystal Oscillator XOUT Frequency Divider Feedback Divider PLL Phase Detector Loop Filter VCO Output Divider ModOUT VSS Pin Configuration XIN VSS D_C 1 8 XOUT VDD FRS ModOUT 2 ASM3P2811A/B ASM3P2812A/B ASM3P2814A/B 7 3 6 SRS 4 5 Low Power EMI Reduction IC Notice: The information in this document is subject to change without notice. 2 of 6 September 2003 ASM3P2811A/B ASM3P2812A/B ASM3P2814A/B www.DataSheet4U.com rev 1.0 Pin Description Pin# 1 2 3 Pin Name XIN VSS D_C Type I P I Description Crystal connection or external frequency input. This pin has dual functions. It can be connected to either an external crystal or an external reference clock. Ground to entire chip. Digital logic input used to select Down (LOW) or Center (HIGH) spread options. (Refer Output Frequency Deviation and Spread Option Selection Table). This pin has an internal pull-up resistor. Spread range select. Digital logic input used to select frequency deviation (Refer Output Frequency Deviation and Spread Option Selection Table). This pin has an internal pull-up resistor. Spread spectrum clock output (Refer Input/Output Frequency Range Selection Table and Output Frequency Deviation and Spread Option Selection Table). Frequency range select. Digital logic input used to select input frequency range (Refer Input/Output Frequency Deviation and Spread Option Selection Table). This pin has an internal pull-up resistor. Power supply for the entire chip (3.3V). Crystal connection. Input connection for an external crystal. If using an external reference, this pin must be left unconnected. 4 SRS I 5 ModOUT O 6 7 8 FRS VDD XOUT I P I Input/Output Frequency Range Selection Table Part Number FRS (pin 6) ASM3P2811 (1X) Input (MHz) 0 1 10-20 20-40 Output (MHz) 10-20 20-40 ASM3P2812 (2X) Input (MHz) 10-20 20-40 Output (MHz) 20-40 40-80 ASM3P2814 (4X) Input (MHz) 10-20 20-40 Output (MHz) 40-80 80-160 Input Frequency / 448 .


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