A 60 GHz frequency divider with quadrature outputs in 130nm SiGe BiCMOS technology for optical OFDM systems

A frequency divider providing quadrature outputs up to 30GHz is presented. Rms phase error and rms clock jitter are discussed in the context of OFDM systems, where the usual phase error correction in the digital baseband processor is included. A measurement technique for the static phase error between the in-phase and quadrature signal is proposed using an integrated single-sideband mixer in conjunction with an integrated 1:256 frequency divider. For a 20GHz I/Q output signal a static phase error of 0.16° is obtained from these measurements. The quadrature divider core draws 35mA from a 3.3 V supply and occupies 0.2 mm2 chip area, including output buffers and two differential delay lines for I/Q adjustment.