A limiting amplifier with low phase deviation using an AlGaAs/GaAs HBT

The design and performance of an AlGaAs/GaAs HBT limiting amplifier are presented. It is revealed that the main cause of phase shift deviation in a limiting amplifier is the bias dependence of the input capacitance, which is the dominant nonlinear factor in a transistor. A circuit design featuring a differential configuration with an emitter peaking technique lowers phase deviation and widens the frequency band. The device achieves high-frequency operation of 15 GHz with a low phase shift deviation of 3 degrees over a 15-dB input dynamic range.<
>