The AD9850 is a highly integrated device designed by ADI that uses advanced DDS technology coupled with an internal, high-speed, high-performance D/A converter and comparator to form a complete, digitally programmable frequency synthesizer and clock generator function. When referenced to an accurate clock source, the AD9850 generates a spectrally pure, frequency/ phase-programmable, analog output sine wave. This sine wave can be used directly as a frequency source or converted to a square wave for agile-clock generator applications.

AD9850’s innovative, high-speed DDS core provides a 32-bit frequency tuning word, which results in an output tuning resolution of 0.0291 Hz for a 125 MHz reference clock input. The AD9850’s circuit architecture allows the generation of output frequencies of up to one-half the reference clock frequency (or 62.5 MHz), and the output frequency can be digitally changed (asynchronously) at a rate of up to 23 million new frequencies per second. The device also provides five bits of digitally controlled phase modulation, which enables phase shifting of its output in increments of 180°, 90°, 45°, 22.5°, 11.25°, and any combination thereof.

The AD9850 also contains a high-speed comparator that can be configured to accept the (externally) filtered output of the DAC to generate a low-jitter square wave output. This facilitates the device’s use as an agile clock generator function.