A compact low-power linear-in-dB CMOS AGC

This paper presents a low-power and compact automatic gain control circuit which consumes only 1.3 mW and occupies only 0.008 mm
²
fabricated in TSMC 0.18-μm CMOS technology. The core of the proposed AGC is a variable gain amplifier (VGA) implemented by Gilbert cells and an exponential function circuit for dB linearity of gain control. The dynamic range of the AGC is from -10 dB to 50 dB. The operation frequency is only 10 MHz, but the AGC maintains 3 dB bandwidth wider than 35 MHz throughout its gain range. The constant time of the AGC loop is 5 μs.