An Inductorless CMOS 0.1-1GHz Automatic Gain Control Circuit

This paper presents an inductorless 0.1-1 GHz automatic gain control (AGC) circuit comprised of a variable gain amplifier (VGA), power detector (PD), and comparator. The VGA has a gain control range of -28~23 dB with a 1 GHz 3-dB gain bandwidth using a cascode amplifier with negative capacitance. The PD shows an input power range of -30~20 dBm using an improved unbalanced source coupled pair, which incorporates an output differential amplifier and sink current steering. The AGC circuit produces constant output power for an input power range of -48 dBm~8 dBm over 0.1~1 GHz without an inductor. The overall current consumption is 7.7 mA under 1.5 V supply. The prototype is fabricated with a 0.18-mum standard CMOS technology.