40ppm Spread Spectrum Oscillators:

We offer a range of spread spectrum oscillators for engineers seeking to design secure communication channels and switched-mode power supplies with low EMI generation

A spread spectrum oscillator is an electronic oscillator that generates a signal whose frequency is deliberately varied over time. The frequency variation is usually accomplished by using a phase-locked loop (PLL) or a delay-locked loop (DLL) in conjunction with a voltage-controlled oscillator (VCO). The purpose of this variation is to reduce the spectral density of the signal and thus reduce electromagnetic interference (EMI) with other devices.

Spread-spectrum techniques are used for the establishment of secure communications, increasing resistance to natural interference, noise, and jamming, to prevent detection, to limit power flux density (e.g., in satellite downlinks), and to enable multiple-access communications.

Analog Devices’ DS1090 Series are low-cost, dithered oscillators intended to be used as an external clock for switched-mode power supplies and other low-frequency applications. The dithering or sweeping function reduces peak-radiated emissions from the power supply at its fundamental frequency, as well as harmonic frequencies.

The devices consists of a resistor-programmed master oscillator, factory-programmed clock prescaler, and a pin-programmed dither circuit. These features allow the DS1090 to be used in applications where a spread-spectrum clock is desired to reduce radiated emissions. A combination of factory-set prescaler and external resistor allows for output frequencies ranging from 125kHz to 8MHz. Both dither frequency and dither percentage are set using control pins.