A DC ~ 4GHz Medium Power Amplifier based on Darlington Pair Topology

A DC ~ 4 GHz medium power amplifier (MPA) is presented. The whole circuit adopts Darlington pair topology. Its input and output matching circuits are designed on the chip. It is fabricated in a standard 0.35 µm silicon-germanium (SiGe) BiCMOS process. It achieves high output 1 dB compression point (P-1dB) of 16.1 dBm at 1 GHz, 14.9 dBm at 2 GHz, 14.0 dBm at 3 GHz, and 13.1 dBm at 4 GHz. Input return loss (S11) and output return loss (S22) are below -10 dB from DC to 4 GHz, which means that the input and output ports achieve good impedance matching in full frequency band. Therefore, it's very suitable for broadband and high output power IF or RF amplification. Moreover, the proposed MPA and other CMOS cell circuits are easy to realize monolithic integration because they can be based on the same SiGe BiCMOS process.