The Method of Bandwidth Extension of SiGe BiCMOS Microwave Variable-Gain Amplifier Integrated Circuit

Abstract

The article proposes a method of bandwidth extension of the analog integrated circuit of the variable-gain amplifier (VGA) based on SiGe BiCMOS technology with the rules of 0.18 µm. The designed VGA has a linear (in dB) control characteristic. The authors consider the VGA architecture and present its design outputs. They describe the properties of two modifications of the VGA integrated circuit – with classical correction of the response and with the circuit of the parasitic capacitance cancellation in the high-impedance node. The article shows that the second circuit solution allows increasing the upper frequency limit of the VGA by a factor of 1.8-2.

Keywords

• variable-gain amplifier
• "folded" casсode
• operational amplifier
• SiGe BiCMOS technology
• R-2R matrix
• cancellation