A Wide Bandwidth Current Mode Filter Technique Using High Power Efficiency Current Amplifiers with Complementary Input

60 GHz wireless communication requires analog baseband circuits having a bandwidth of about 1 GHz. This paper presents a wide bandwidth current-mode low pass filter technique which involves current amplifiers, resistors and capacitors. The proposed current-mode filter is obtained by replacing an integrator employing an op-amp with another integrator employing a current amplifier. With the low input impedance current amplifier having little variation of the input impedance, the proposed filter is expected to improve linearity and power efficiency. The proposed current amplifier which employs super source follower topology with complementary input is suitable for the filter because of its class AB operation. Although simulation results shows the conventional current amplifier which employs super source follower topology without the complementary input has 12 Omega variation and 30 Omega input impedance, the proposed current amplifier has 1 Omega variation and 21 Omega input impedance. A fourth order 1 GHz bandwidth filter which involves the proposed current amplifiers is designed in a 65 nm CMOS technology. The filter can achieve IIP3 of 1.3 dBV and noise of 0.6 mVrms with power consumption of 13 mWunder supply voltage of 1.2V according to simulation results with layout parasitic extraction models. Active area of the filter is 380 mu m x 170 mu m.