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INA280: 静态输出电压为什么会有4.7mv?

Part Number: INA280

采样电阻0.5mΩ,芯片为INA280A2,gain为50v/v,按照官方推荐电路焊好电路,在没有加载负载时(采样电阻两端电压为0.002mv),INA280静态输出电压高4.7mv,为什么会这么高,而且在加入不同负载使采样电阻两端电压为0.1mv~0.5mv时,输出电压为5mv~25mv,符合gain特性参数,也就是说,在采样电阻两端电压小于0.1mv时,输出电压都是4.7mv左右,换了3片芯片都一样。

  • 您好,datasheet中有介绍:The linear range of the output stage is limited to how close the output voltage can approach ground under zero input conditions. The zero current output voltage of the INA280 is very small, with a maximum of GND + 25 mV. Make sure to apply a sense voltage of (25 mV / Gain) or greater to keep the INA280 output in the linear region of operation。

    输出端的线性范围是受限于在零输入条件下输出电压接近0V电压的大小。INA280 在输入电流为0时,输出电压最大为GND+25mV. 如果要确保输出工作在线性范围内,建议采样电阻两端的电压不小于25mV/Gain. 因此如果GAIN=50的话,建议采样电压不小于0.5mV。 所以您在测试0.1mv~0.5mv电压范围时,输出还是可以保持在线性范围内的,但是不推荐小于0.5mV内使用的呢。