2020•2020 Intermountain Engineering, Technology and Computing (IETC)Requires access
Design of Common-Mode Feedback for High-Gain Charge Amplifier
Yixin Song, Jace Rozsa, Joan Barros de Magalhaes, Shea Smith, Benjamin Karlinsey, Whitney Kinnison, Elaura L. Gustafson, Daniel E. Austin, Aaron R. Hawkins, Shiuh-Hua Wood Chiang
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Abstract
We describe a common-mode feedback circuit (CMFB) for a charge detector. The amplifier is implemented in a 180-nm complementary metal-oxide-semiconductor (CMOS) process. The amplifier combines a folded differential topology, active reset, and small feedback capacitors. This allows for low noise, high-gain, high-dynamic-range, and robust operations. The design and analysis of the CMFB for the proposed high-gain charge amplifier is discussed. Simulation results show that the CMFB loop has a phase margin of 62.1 degrees and a gain margin of 25 dB. Measurement results show the amplifier chip exhibits a stable common mode voltage.