关于负压采集的问题

你好!

现在需要采集一个-28V电压,打算用TI厂家的ADS8691 ADC,单电源供电就可采集负压。

但是ADS8691的输入范围最大是+/-12V,能否在模拟输入端进行调理(比如串一个Mohm级电阻)来扩大输入范围?

手册P24有提到如下:

The results indicated in Table 1 are based on an assumption that the analog input pin is driven by a very low
impedance source (R S is approximately 0 Ω). However, if the source driving the input has higher impedance, the
current flowing through the protection diodes reduces further, thereby increasing the OVP voltage range. Higher
source impedances result in gain errors and contribute to overall system noise performance.

请问在精度要求不高的情况下,如何将采样范围提高?

还望不吝指教,谢谢!

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