A DDS-oriented phase-to-amplitude converter using a SiGe:C bipolar transistors differential pair

A phase-to-amplitude converter using a bipolar transistor differential pair with an 8-bits digital-to-analog converter is reported. This technique provides significant saving in power consumption and die size due to the elimination of the ROM and/or complex compute circuit. It renders the design of direct digital synthesizer usable for microwave wireless systems. The circuit has been processed in 0.25 /spl mu/ BiCMOS SiGe: C technology. The measured rejection for the first and the second harmonic is respectively -37 dBc and -63 dBc. The 8-bits D/A converter integral non-linearity and differential non-linearity errors are under 1 LSB. The circuit power consumption is 115 mW and operates from a single 2.7 V supply.