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Is it possible to bypass AD8244 input capacitance (4pF is rather high)

Question asked by winio on Nov 7, 2016
Latest reply on Feb 17, 2017 by christoliver

I plan to use AD8244 as a input in an EEG amplifier. Using AD8244 I can achieve extremally high DC-impedance (resistance), but the capacity is still 4pF. 4pF paralelly with 10TOhm for 10Hz (alpha band in EEG) degrades DC-impedance a lot.

Is it any possibility to bypass this rather high AD8244's inut capacity? I was thinking about using some high-frequency transistor (for example BFP405 has capacity as low as 0,3pF) as voltage follower, but how to design it in order not to degrade DC-impedance?

 

regards,

Mateusz Winkowski

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