DC to 12+GHz, +30dBm OIP3, 7.2dB Noise Figure Active Balun in 130nm BiCMOS for RF Sampling Multi-Gbps Data Converters

An active balun using dual stage feedback and distributed feedforward distortion cancellation for use as a driver amplifier for wideband RF sampling ADCs is presented. With a gain of 16.5dB & HD2 of 60dBc while delivering 3dBm (100Ω), the DC coupled balun achieves a linear-bandwidth of >12GHz holding OIP3>27dBm & NF<8dB, and small-signal bandwidth of 18GHz with <±0.5dB amplitude & <±2.5° phase imbalance. Cascaded balun + ADC measurements demonstrate no linearity limitation, while allowing for 19.5dB lower input signal. Occupying 1mm²in a 130nm BiCMOS process, the device consumes 100mA from 5V in a 2×2mm² flip chip QFN package.