TLV7012: RC low pass filter with a "hard" cut-off frequency

My customer consider using a (window) comparator to provide an RC low pass (excited by one of your SN74LVC1G17) with a "hard" cut-off frequency. This means that from a certain attenuation through the comparator a quasi digital cutoff frequency can be achieved.

The focus here is on the hard limit frequency and the lowest possible space consumption at operating temperatures up to 120°C.

With your filter design tool and other considerations/simulations, I don't get to a more compact circuit that has a digital cutoff frequency.

Can you please suggest solutions or parts for this application.

(I have posted it in logic forum before: e2e.ti.com/.../3791787

Thanks 

Jan