A 2.7 mW, 0.064 mm/sup 2/ linear-in-dB VGA with 60 dB tuning range, 100 MHz bandwidth, and two DC offset cancellation loops

Abstract

This paper presents a low-power and small-size variable gain amplifier (VGA) which consumes only 2.7 mW and occupies only 243 /spl mu/m /spl times/ 264 /spl mu/m (/spl sim/0.064 mm/sup 2/) in 0.18-/spl mu/m CMOS technology. The VGA is fully differential with differential output swing of 1-V/sub pp/. The gain (in dB) of the VGA can be varied linearly from -3 dB to 57 dB with respect to a control voltage from 0.2 V to 0.9 V. The VGA has a 3-dB bandwidth of more than 100 MHz for all levels of gain. The VGA also has two DC offset cancellation loops to avoid the amplification of DC offset. The output DC offset of the VGA is less than 20 mV even if an input DC offset of 40 mV is introduced to the VGA. Low power consumption is obtained owing to high transition frequency of the transistors in 0.18-/spl mu/m CMOS technology. Small area is achieved by minimizing the passive component's values and areas.