A 2.7 mW, 0.064 mm2 linear-in-dB VGA with 60 dB tuning range, 100 MHz bandwidth, and two DC offset cancellation loops

This paper presents a low-power and small-size variable gain amplifier (VGA) which consumes only 2.7 mW and occupies only 243 μm × 264 μm (∼0.064 mm²) in 0.18-μm CMOS technology. The VGA is fully differential with differential output swing of 1-V_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-μm CMOS technology. Small area is achieved by minimizing the passive component´s values and areas.