CMOS High Frequency Distributed Active Balun
Tech ID: 21589 / UC Case 2011-218-0
Baluns are extensively used for single-to-differential conversion of analog/RF/millimeter-wave/broadband signals in integrated transceivers as well as test/measurement equipment setup. Passive baluns do not consume dc power, but suffer from signal attenuation as well as being limited to narrow bands. Active baluns provide power gain and wideband operation while consuming power from dc power supply. This invention is a novel design of an active balun that improves voltage gain and linearity without sacrificing power, bandwidth or physical area.
The proposed distributed active balun uses distributed architecture with a single-ended input line and differential output lines to improve the gain-bandwidth product. The distributed balun includes multi-stage gain cells to increase power gain. Each gain stage employs new bandwidth-enhancement circuitry to compensate for bandwidth degradation due to multi-stage design. The resulting distributed active balun has been implemented in 65nm CMOS technology. Measurement results show an active gain of 4dB across bandwidth >70GHz (measurement limited to speed of test equipment), which demonstrates significant improvement in gain-bandwidth compared to prior art.
Broadband wireless/wired transceiver design, multi-purpose broadband test/measurement equipment.
Overall gain is improved without degrading bandwidth. This enablement also improves the overall linearity of the gm stage. These improvements do not increase power consumption or physical area.
CMOS, amplifier, balun, broadband, wireless communication, wired communication