ASM3P2872A Datasheet | Alliance Semiconductor Corporation

Features - - - - - - - - - Generates an EMI optimized clock signal at the output Integrated loop filter ponents Operates with a 3.3V / 2.5V supply Operating current less than 6m A Low power CMOS design Input frequency range: 13MHz to 30MHz for 2.5V : 13MHz to 30MHz for 3.3V Generates a 1X low EMI spread spectrum clock of the input frequency Frequency deviation: -1.25% @ 30MHz Available in 6-pin TSOT-23, 8-pin SOIC and 8-pin TSSOP packages. The ASM3P2872A uses the most efficient and optimized modulation profile approved by the FCC and is implemented by using a proprietary all digital method. The ASM3P2872A 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 The ASM3P2872A is targeted towards all portable devices with very low power requirements like MP3 players, Notebooks and digital still cameras. Product Description The ASM3P2872A is a versatile spread spectrum frequency modulator designed specifically for a wide range of clock frequencies. The ASM3P2872A reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of all clock dependent signals. The ASM3P2872A allows significant system cost savings by reducing the number of circuit board layers ferrite beads, shielding that are traditionally required to pass EMI regulations. Key Specifications Description Supply voltages Cycle-to-Cycle Jitter Output Duty Cycle Modulation Rate Equation Frequency Deviation Specification VDD = 3.3V /2.5V 200p S (Max) 45/55% (worst case) FIN/640 -1.25% @ 30MHz Block Diagram Modulation XIN XOUT Crystal Oscillator Frequency Divider Feedback Divider REFOUT Phase Detector Loop...