title: Note: A temperature-stable low-noise transimpedance amplifier for microcurrent measurement.
abstract: Temperature stability and noise characteristics often run contradictory in microcurrent (e.g., pA-scale) measurement instruments because low-noise performance requires high-value resistors with relatively poor temperature coefficients. A low-noise transimpedance amplifier with high-temperature stability, which involves an active compensation mechanism to overcome the temperature drift mainly caused by high-value resistors, is presented. The implementation uses a specially designed R-2R compensating network to provide programmable current gain with extra-fine trimming resolution. The temperature drifts of all components (e.g., feedback resistors, operational amplifiers, and the R-2R network itself) are compensated simultaneously. Therefore, both low-temperature drift and ultra-low-noise performance can be achieved. With a current gain of 1011V/A, the internal current noise density was about 0.4 fA/√Hz, and the average temperature coefficient was 4.3 ppm/K at 0-50 °C. The amplifier module maintains accuracy across a wide temperature range without additional thermal stabilization, and its compact size makes it especially suitable for high-precision, low-current measurement in outdoor environments for applications such as electrochemical emission supervision, air pollution particles analysis, radiation monitoring, and bioelectricity.
authors.affiliation: School of Aerospace Science and Technology, Xidian University, Xi'an 710071, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Xie
authors.affiliation: School of Aerospace Science and Technology, Xidian University, Xi'an 710071, China.
authors.forename: Xueyou
authors.identifier: 0000000244518966
authors.initials: X
authors.lastname: Shi
authors.affiliation: School of Aerospace Science and Technology, Xidian University, Xi'an 710071, China.
authors.forename: Kai
authors.identifier: 0000000328013586
authors.initials: K
authors.lastname: Zhao
authors.affiliation: School of Physics and Optoelectronic Engineering, Xidian University, Xi'an 710071, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Guo
authors.affiliation: School of Communication and Information Engineering, Xi'an University of Posts and Telecommunication, Xi'an 710121, China.
authors.forename: Hanlu
authors.initials: H
authors.lastname: Zhang