CMOS Wideband Low-Pass Filter Using Complementary Structured OPAMP for Wideband System Applications

In this paper, a CMOS wideband low-pass filter is proposed. In the wide band active filter design, the unit gain frequency (GBW) of OPAMP should be larger than GHz. The GBW of the proposed OPAMP is around 2.3 GHz. Additionally, the OPAMP with a complementary structure in signal and common mode feedback is proposed and has a wide operating voltage range at the input and output. The 1-dB gain compression point (P1dB) at the output is 4.9 dBm. A source follower is employed for driving 50 Ω output impedance without degrading the bandwidth and linearity of the filter. The power consumption is 27 mW from a 1-V supply voltage. The 3 dB bandwidth of the filter ranges from 330 MHz to 660 MHz with 3-bit cap tuning. This work is implemented in a 65-nm CMOS process, with a chip area of 0.18 mm2.