基于全国产化器件的0.1pA级微电流跨阻放大器电路设计

Background]: In nuclear radiation detection, detectors that output microcurrents commonly use the ADA4530 chip, designed and manufactured by Analog Devices, Inc. (ADI), to construct transimpedance amplifier circuits for measuring microcurrent signals. [Purpose]:To address the issue of dependency on foreign technology in the field of weak current measurement and to achieve the goal of designing weak current amplification circuits using entirely domestic components. [Methods]:The circuit design uses entirely domestic components and is based on the I-V conversion method for transimpedance amplification. [Results]: After careful design considerations and the selection of domestic components, a microcurrent transimpedance amplifier circuit with an output voltage range of 0 to 10V was successfully constructed. [Conclusions]:Testing showed that with a feedback resistor of 100G, the linear fit for an input current of 0.1 to 100pA had an R2value of 0.99998, a relative deviation of less than 0.235%, and a noise peak-to-peak value of 0.057pA. When the feedback resistor is 10Gand the input current is 1pA, the temperature drift over a range of -10to 80 is less than 0.042pA/. When the feedback resistor is 10Gand the input is left floating, the output drift is less than 0.2662pA during a 6-hour stability test at room temperatu