VFA, CFA, Bipolar or CMOS - Which High-Speed Amplifier Is Best for Your Low-Noise Application VFA, CFA, Bipolar or CMOS - Which High-Speed Amplifier Is Best for Your Low-Noise Application? Application Note November 1, 2005 AN1213.0 Introduction source. Note that any difference (signal or error) in the currents of the signal-path transistors appears across the Ten years ago, the bandwidth of a state-of-the-art high- output impedance of the current sourc……