For the AD8302 the datasheet describes the cap changes to make up to 1kHz. Our target frequency is 100kHz. With this target frequency, what are the cap changes that are required to ensure the 8302 works as designed?
Please take a look at the attached app note. Page 13 is section on the AD8302.
Thank you for the appnote.
I see where AN-691 discusses the AD8302 with a target frequency up to 20kHz.
I can see that the schematic changes slightly for low frequency operation. Not sure if 100kHz is considered low, intermediate, or high frequency. How do I extrapolate the value of the capacitors that I need for operation at a target frequency of 100k from AN-691?
There is a closed form equation on page 16 of the AD8302 datasheet for the C_FLT caps, T (ns) = 3.3*C_ave (pF). With a 1uF cap, the low pass corner is 48 Hz. The time constant for the input is roughly: tau = Cc * 3k. I would start by using 1uF caps for both the input coupling caps and filter caps. This yields a high pass corner of 53 Hz, which should be more than low enough for your application.
Hope this helps,
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