A low-power wide gain range digitally controlled variable gain amplifier with a wide tuning bandwidth for 60 GHz applications

This paper presents a wide gain range variable gain amplifier (VGA) for the low-power 60 GHz wireless receiver in a 65-nm CMOS. The proposed VGA consists of an input high pass filter (HPF), four-stage VGA core, a DC offset cancellation (DCOC) unit and an output buffer for the test purpose. By introducing the novel digitally controlled resistors and capacitors array network, the VGA can meet the single channel and the channel bonding applications. Test results show that, with a gain range of about 64 dB, a tuning 3-dB bandwidth about from 700 MHz to 1 GHz is achieved. With a gain range of 55 dB, a tuning 3-dB bandwidth about from 700 MHz to 1.76 GHz is achieved. With the DCOC unit, the output dc offset voltage is reduced from hundred millivolts to 6mV. The two-channel VGA (I+Q) consume only 20 mA from a 1.4 V supply and the core area is only 0.04mm².