i have made an input ectension circuit on the ad7746 evaluation board.
i have calculated the extension circuit values for an input capacitance of 146pF
based on that my resistor values are R1=100.04k R2=125.7k
C_dynamic range=+/- 36.03
i have few confusion
Does the dynamic range means i can connect any capacitance within the range of (146+/-36.03)pF
Now i have connected 155pF to the input with
setting capdac A as 0x7D
enabling capacitive channel
exc setup as 1B
the data registers in continuous conversion mode read as=7A4572
capacitance is shown as(-0.183319)
how can i calculate the real capacitance based on these values?