A high performance band-pass DAC architecture and design targeting a low voltage silicon process

Direct Digital Synthesis (DDS) systems generate adjustable high resolution phase and frequency signals that are used in a wide variety of applications such as multi-mode RF, communications, measurements and test. A high performance band-pass DAC architecture and implementation is presented that delivers high spectral purity over a narrow-band response. The low power DAC is portable to standard CMOS processes and achieves 110dB narrowband SFDR performance using sigma-delta (μΔ) modulation and multi-bit current steering techniques. A 3rd order digital μΔ modulator is combined with a 4th order digital Dynamic Element Matching (DEM) block to shape the noise while calibrating for process mismatch variations. A low silicon area output stage is used to deliver a high performance specification.