A Bandpass /spl Delta//spl Sigma/ RF-DAC with Embedded FIR Reconstruction Filter

Abstract

A 1b bandpass DeltaSigma DAC followed by a current steering FIR reconstruction filter and an embedded up-conversion mixer is presented. The RF DAC is implemented in 0.25μm digital CMOS, can be used in low-power digital-IF transmitters and eliminates the need for a transimpedance stage and a separate mixer. The RF DAC draws 49mA from a 2.5V supply, achieving -64.7dBc IM3 at 1.03GHz with an SFDR of 72dB in a 15MHz bandwidth