Optically Powered Sub-1 dB Noise Figure CMOS LNA for Magnetic Resonance Imaging

Senturk M., DÜNDAR G., YALÇINKAYA A. D.

21st International Conference on Synthesis, Modeling, Analysis and Simulation Methods, and Applications to Circuits Design, SMACD 2025, İstanbul, Türkiye, 7 - 10 Temmuz 2025, (Tam Metin Bildiri) identifier identifier

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Doi Numarası: 10.1109/smacd65553.2025.11092139
  • Basıldığı Şehir: İstanbul
  • Basıldığı Ülke: Türkiye
  • Anahtar Kelimeler: Magnetic Resonance Imaging (MRI), Low-Noise Amplifier (LNA), CMOS, Inductive Degeneration, Optical Powering
  • Boğaziçi Üniversitesi Adresli: Evet

Özet

This paper presents two low-voltage, sub-1 dB Noise Figure (NF) CMOS Low-Noise-Amplifiers which have been designed to be used as a preamp for an optically powered magnetic resonance imaging (MRI) front-end. The operation frequency is 64 MHz, which is the 1.5 T MRI Larmor Frequency of a hydrogen atom. The design is shown to satisfy the NF requirements at 3T & 7T as well. By utilizing a photodiode as an optical power supply, the design uses 2 mA of total bias current and only 0.7 V power supply to attain the awaited noise requirements. The first topology utilizes a telescopic cascode structure with transformer-based inductive source degeneration and a common-mode feedback loop. The initial system attains a ~ 0.147 dB noise figure at 64 MHz with direct 50 Ω matching. The second topology is an NMOS cascode stage with resistive loads. This topology attains a noise figure of ~ 0.352 dB when optimized for noise matching.