Journal of East China Normal University(Natural Science) ›› 2022, Vol. 2022 ›› Issue (2): 143-154.doi: 10.3969/j.issn.1000-5641.2022.02.017

• Physics and Electronics • Previous Articles    

Design of a reconfigurable active filter chip

Junwei YU, Shengxi DIAO*()   

  1. School of Communication and Electronic Engineering, East China Normal University, Shanghai 200241, China
  • Received:2020-12-25 Online:2022-03-25 Published:2022-03-28
  • Contact: Shengxi DIAO


Recently, research on multi-mode, multi-band transceivers has garnered significant interest; in this context, the Software-Define Radio (SDR) system is considered a good candidate. To reduce the negative influence of out-of-band interference on transceiver performance of the SDR system, a high out-of-band rejection IF (intermediate frequency) filter with tunable bandwidth and programable gain is proposed. The proposed filter consists of a biquadratic Gm-C filter, a gain-boosting stage, and a 5th-order elliptic filter. In the proposed filter, the variable gain is achieved using a biquadratic Gm-C filter and a gain-boosting stage, and the tunable bandwidth is achieved using capacitor arrays. In addition, a 5th-order elliptic filter is added to improve out-of-band rejection. The post-layout simulation shows that the bandwidth is tuned over a range of 1 MHz–30 MHz, and the minimum out-of-band rejection at twice the bandwidth reaches 44.56 dB. The gain control range is from –20 dB to 20 dB, and the power consumption and active area for the analog counterpart is 5.1 mW and 1.23 mm2, respectively. The proposed filter is suitable for the analog front-end of multi-mode communication terminals.

Key words: active filter, bandwidth tunable, gain programable, high out-of-band rejection, low power consumption

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