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AD7745/46  allowed capacitance to GND and CN0129

Question asked by Terumasa on Nov 30, 2015
Latest reply on Dec 8, 2015 by Terumasa



My customer is interested in AD7745/46 and so on using CN0129.

His input capacitance range will be ~ 200pF MAX

Could you gibe me your advice about below my question for input range extension and allowed capacitance to GND.


AD7745/46 Datasheet p.3 says that allowed capacitance to GND  in excitation is 100pF MAX. 

Does above mean that EXC pin can not connect  any sensor  which has capacitance over 100pF ?


AD7745/46 datasheet p.8 Figure 11 says capacitance error   in capacitance to GND over 100pF

CN0129 P.3 figure 2 says capacitance error  about ~ 200pF +- 45pF.


I understand that using any sensor over 100pF affects measurement error but we can use any sensor over 100pF.

Is my understanding correct ?


Please let me know your advice.