ASM3P2183A

ASM3P2183A EMI Reduction IC Description The ASM3P2183A is a versatile spread spectrum frequency modulator designed specifically for a wide range of input clock frequencies from 6 MHz to 90 MHz. (Refer to Input Frequency and Modulation Rate Table). The ASM3P2183A can generate an EMI reduced clock from an OSC or a system generated clock. The ASM3P2183A offers a Down Spread clock with a percentage deviation of −1.25% and a Center Spread clock with a percentage deviation of ± 0.42%. The ASM3P2183A reduces electromagnetic interference (EMI) at the clock source, allowing system wide reduction of EMI of down stream clock and data dependent signals. The ASM3P2183A 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 ASM3P2183A uses the most efficient and optimized modulation profile approved by the FCC and is implemented in a proprietary all digital method. The ASM3P2183A 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.’ Applications The ASM3P2183A is targeted towards EMI management for me...