A CMOS power-efficient low-noise current-mode front-end amplifier for neural signal recording

Chung-Yu Wu, Wei Ming Chen, Liang Ting Kuo

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


In this paper, a new current-mode front-end amplifier (CMFEA) for neural signal recording systems is proposed. In the proposed CMFEA, a current-mode preamplifier with an active feedback loop operated at very low frequency is designed as the first gain stage to bypass any dc offset current generated by the electrode-tissue interface and to achieve a low high-pass cutoff frequency below 0.5 Hz. No reset signal or ultra-large pseudo resistor is required. The current-mode preamplifier has low dc operation current to enhance low-noise performance and decrease power consumption. A programmable current gain stage is adopted to provide adjustable gain for adaptive signal scaling. A following current-mode filter is designed to adjust the low-pass cutoff frequency for different neural signals. The proposed CMFEA is designed and fabricated in 0.18-μm CMOS technology and the area of the core circuit is 0.076 mm 2. The measured high-pass cutoff frequency is as low as 0.3 Hz and the low-pass cutoff frequency is adjustable from 1 kHz to 10 kHz. The measured maximum current gain is 55.9 dB. The measured input-referred current noise density is 153 fA Hz , and the power consumption is 13 μW at 1-V power supply. The fabricated CMFEA has been successfully applied to the animal test for recording the seizure ECoG of Long-Evan rats.

Original languageEnglish
Article number6508911
Pages (from-to)107-114
Number of pages8
JournalIEEE Transactions on Biomedical Circuits and Systems
Issue number2
StatePublished - 30 Apr 2013


  • Current-mode
  • front-end
  • low-noise low power design
  • neural recording
  • offset cancellation

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