The AD9831ASTZ is a Direct Digital Synthesizer Waveform Generator with on-chip 10-bit DAC. Numerically controlled oscillator employing a phase accumulator, a sine look-up integrated on a single CMOS chip. Modulation capabilities are provided for phase modulation and frequency modulation. Clock rates up to 25MHz are supported. Frequency accuracy can be controlled to one part in 4 billion. Modulation is effected by loading registers through the parallel microprocessor interface. A powerdown pin allows external control of a powerdown mode.