Cannot replicate datasheet circuit with LTC1060


I am working with the LTC1060 filter, and I am trying to replicate the circuit in the typical application on the LTC1060 datasheet. I'm trying to get the same amplitude response as shown in the datasheet, but the FFT looks very messy. My end goal is to use the LTC6900 or LTC6930 in conjunction with the LTC1060 to pass lower frequencies in the 10-100 Hz range. Is there something wrong with my diagram? Is there a problem with my input source?



Secondly, in the FFT of the output voltage there is always a peak at 20V. Is there any reason for this? Is there a way to remove this?

Thank you in advance for the help!