A 500-MHz Sigma-Delta Phase-Interpolation Direct Digital Synthesizer

A SigmaDelta phase-interpolation direct digital synthesizer (DDS) is presented. This DDS generates frequencies from 400 MHz up to 500 MHz. Phase interpolation uses dual slope integration on a single capacitor and current is provided by a digital to analog converter (DAC). The SigmaDelta enables high frequency resolution and shapes quantization noise. The DDS has been integrated on a 65-nm CMOS STMicroclectronics technology. The power consumption is about 29 mVV without buffers under 1.2 V for a 500-MHz operating frequency.