P2782 Datasheet | Alliance Semiconductor

Features - - - - - - - - - - - - - - Provides up to 15d B of EMI suppression FCC approved method of EMI attenuation Generates a 1X, 2X, and 4X low EMI spread spectrum clock of the input frequency Input frequency range from 3 to 78MHz External loop filter for spread % adjustment Spreading ranges from ±0.25% to ±5.0% Ultra low cycle-to-cycle jitter Zero-cycle slip 3.3V operating voltage range 10 m A output drives TTL or CMOS patible outputs Ultra-low power CMOS design P278XA is available in 8 pin SOIC and TSSOP Packages Available for industrial and automotive temperature ranges. P2781/82/84 other digital video and imaging applications. The P278x A reduces electromagnetic interference (EMI) at the clock source, which provides system wide reduction of EMI of all clock dependent signals. The P278x A allows significant system cost savings by reducing the number of circuit board layers and shielding that are traditionally required to pass EMI regulations. The P278x A uses the most efficient and optimized modulation profile approved by the FCC. The P278x A 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 pared 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. Applications Product Description The P278x A is a versatile spread spectrum frequency modulator designed specifically for digital camera and The P278x A is targeted towards MFP, x DSL, fax modem, set-top box, USB controller, DSC, and embedded systems. Block Diagram FS0 FS1 PLL Modulation XIN /CLKIN XOUT Crystal Oscillator Frequency Divider Feedback Divider Phase Detector VCO Output Divider .. Mod OUT Alliance Semiconductor 2575, Augustine Drive - Santa Clara, CA - Tel: 408.855.4900 - Fax: 408.855.4999 -...