Low-Power Highly Selective Channel Filtering Using a Transconductor–Capacitor Analog FIR

Bart J. Thijssen*, Eric A.M. Klumperink, Philip Quinlan, Bram Nauta

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

13 Citations (Scopus)
383 Downloads (Pure)


Analog finite-impulse-response (AFIR) filtering is proposed to realize low-power channel selection filters for the Internet-of-Things receivers. High selectivity is achieved using an architecture based on only a single-time-varying- transconductance and integration capacitor. The transconductance is implemented as a digital-to-analog converter and is programmable by an on-chip memory. The AFIR operating principle is shown step by step, including its complete transfer function with aliasing. The filter bandwidth and transfer function are highly programmable through the transconductance coefficients and clock frequency. Moreover, the transconductance programmability allows an almost ideal filter response to be realized by careful analysis and compensation of the parasitic circuit impairments. The filter, manufactured in 22-nm FDSOI, has an active area of 0.09 mm2. Its bandwidth can be accurately tuned from 0.06 to 3.4 MHz. The filter consumes 92 µW from a 700-mV supply. This low power consumption is combined with a high selectivity: f−60 dB/f−3 dB = 3.8. The filter has 31.5-dB gain and 12-nV/√ Hz input-referred noise for a 0.43-MHz bandwidth. The OIP3 is 28 dBm, independent of the frequency offset. The output-referred 1-dB-compression point is 3.7 dBm, and the in-band gain compresses by 1 dB for an −3.7-dBm out-of-band input signal while still providing >60 dB of filtering.
Original languageEnglish
Article number9081951
Pages (from-to)1785-1795
Number of pages11
JournalIEEE journal of solid-state circuits
Issue number7
Publication statusPublished - 1 Jul 2020


  • Finite impulse response filters
  • Bandwidth
  • Transconductance
  • Power demand
  • Receivers
  • Capacitors
  • Transfer functions


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