The DS1083L is a spread-spectrum clock modulator IC that reduces EMI in high-clock, frequency-based, digital electronic equipment. Using an integrated phase-locked loop (PLL), the DS1083L accepts an input clock signal in the range of 16MHz to 134MHz and delivers a spread-spectrum modulated output clock signal. The PLL modulates, or dithers, the output clock about the center input frequency at a pin-selectable magnitude. The DS1083L automatically adjusts the dither rate based on the input clock frequency to maximize the EMI reduction. By dithering the system clock, all the address, data, and timing signals generated from this signal are also dithered so that the measured EMI at the fundamental and harmonic frequencies is greatly reduced. This is accomplished without changing clock rise/fall times or adding the space, weight, design time, and cost associated with mechanical shielding. The DS1083L is provided in a low-cost, space-saving, 6-lead thin SOT23 package and operates over a full automotive temperature range of -40°C to +125°C.
Modulates a 16MHz to 134MHz Clock with Center Spread-Spectrum Dithering