A 2–6 GHz Reconfigurable High Dynamic Range Receiver With Wideband Variable Gain LNA

A wideband high dynamic range software radio receiver for sub-6-GHz applications is proposed. The receiver combines three gain variable modules and an automatic gain control module to achieve high gain dynamic range and constant output voltage. A broadband resistive feedback LNA was designed, and two novel gain switching methods were proposed for the resistive feedback LNA, which reduced the LNA gain while optimizing the input matching performance. In addition, the receiver adopts a voltage mode mixer and uses the impedance translation property to achieve blocker-tolerant performance. In analog baseband (ABB), a fourth-order Butterworth active-RC low-pass filter (LPF) is employed for the purpose of attenuating interference. Furthermore, the receiver is furnished with an automatic gain control amplifier to uphold a consistent output voltage amplitude. A 22 nm CMOS receiver prototype occupies 1.85 mm2 and consumes 51 mW from a 1 V power supply over the 2–6 GHz operating frequency range. The receiver achieves a gain dynamic range of 9.1-91.9 dB and a noise figure (NF) of 2.4-3.4 dB. When a 0 dBm blocker with a frequency offset of 80 MHz is injected into the receiver, the NF increases to 13.2 dB. The programmable bandwidth of the LPF can be adjusted from 10 to 160 MHz. Moreover, the receiver achieved an in-band third-order input-referred intercept point (IIP3) of −9.1 dBm and an out-of-band IIP3 of −2.9 dBm respectively.