A 0.7 V tunable gain low noise amplifier for lower band DS-UWB applications

A 0.7V tunable gain low noise amplifier (LNA) is presented for operation in direct sequential ultra-wideband (DSUWB) systems. The configuration consists of one common-gate input stage and two common-source stages. A variable resistor is added to the first stage for obtaining the tunable gain and increasing the linearity. The second and the third stages are cascaded by a resistive shunt feedback to extend the bandwidth. The proposed LNA is simulated by tsmc 0.18 mum CMOS process. The gain tuning range is within 12.4 to 16.3dB. The input thirdorder intercept point (IIP3) is between -1.2 dBm and -7.8 dBm. The -3 dB bandwidth is from 1.8 GHz to 7.2 GHz which is suitable for lower band of DS-UWB systems. The gain (S21) is 15.3~16.3 dB. The input/output reflection coefficients are both lower than -10 dB. The minimum noise figure is 4.28 dB. The power consumption is 7.2m W at 0.7 V supply voltage.