High-Frequency Low-Noise Amplifiers and Low-Jitter Oscillators in SiGe:C BiCMOS Technology

This paper describes the design of noise-critical circuits for radio-frequency and high-speed digital applications in a SiGe:C BiCMOS technology. Starting with a figure of merit for the high-frequency noise behavior of bipolar transistors, challenges in the transistor design are formulated. It is shown that the addition of carbon to the base of a SiGe-HBT results in an excellent high-frequency noise behavior of the transistors. A first design of a differential three-stage lownoise amplifier for 60 GHz applications is presented having a gain of 18 dB at 50 GHz. Furthermore, a 60 GHz voltagecontrolled oscillator is presented with a phase noise of –90 dBc/Hz at 1 MHz offset from the oscillation frequency. Using a first-order PLL model, we predict an rms jitter contribution to a 5 MHz-bandwidth PLL as low as 0.4 percent of the oscillation period. Possible applications include wireless and wired broadband communication as well as automotive radar.