Hi,
with regard to the dc input impedance, in the electrical characteristics table of the ads129x datasheet a distinction is made between current source lead-off detection and pull-up resistor lead-off detection. In the first case, it's 500MOhm, in the latter only 10MOhm. I want to make use of an ac lead-off detection. Now I wonder if that belongs to the pull-up resistor lead-off detection. Having read the AC lead-off detection section, I expect the inner ac signal generation circuitry to reduce the input impedance, but I'm not sure. So, is it reduced to 10MOhm when using the ac generation circuitry?
I want to make use of the internally generated WCT voltage for the negative inputs of the PGAs. According to the datasheet, the WCT terminal should only be used to drive very high impedances (>500MOhm). So, if the input impedance is reduced to 10MOhm through the ac lead-off detection, I cannot use the WCT for the negative inputs. Or can I?
Thank you in advance.
Martin