FDC1004测量值跳变

最近在用FDC1004做电容检测的时候，量程为32pf，

先检测1号位再检测2号位，在1号位和2号位，1号位电容值在4pf左右，2号位电容值在5pf左右。

但是突然有一次，在1号位的位置，检测到电容值突然变为15pf左右，同时2号位的电容值检测的是正常的（数值在5pf）。

在这一次之后，在1号位这个位置，检测到的电容值一直都为7pf左右，但是2号位的电容值检测是正常的，在5pf左右。

这样的情况并非频繁发生，请大神出出主意是什么原因

NickNick：

TI的大神在哪里？

Jimmy Zhou95：

Hi, Are you using the FDC1004EVM or a different board? The FDC1004 will detect all capacitances on the sensor path, not just the capacitance of the sensor itself. The shield pins can be used to minimize parasitic capacitances along the sensor path, but the sensor will still be sensitive to dielectric changes in its vicinity. If the capacitance saturates (which is what is happening when it measures 15pF), there has likely been a change in the environment surrounding the sensor that has significantly increased the capacitance. Regards,

NickNick：

回复 Jimmy Zhou95:

hello，Jimmy
I am using the FDC1004DGST,which is a chip,and according to the datasheet,i designed a circuitry。Also,i make a test for about several monthsand questiones happened.I writed on the top.and,when the capacitancehas significantly increased , the dielectric does notchange in its vicinity.I have no idea about that.

NickNick：

我想知道芯片在什么情况下会出现转换异常呢？

NickNick：

目前发现是芯片转换出来的数据就是那么大…………..