ACS758KCB Wiring Diagram
Cf and Rf form a first-order low-pass filter with a cutoff frequency \$f_C =  \frac {1}{2\pi R C}\$. The response will be reduced to 0.707 (1/2 power) at that frequency. A first-order filter response only drops by -6dB/octave, so attenuation only increases gently. 

The maximum value of Rf is determined by the requirements of whatever it is connected to, and perhaps the leakage of the capacitor. The minimum value is determined by the capability of the part, and 4.7K is specified. If you were to try to use, say, 10M ohm you'd need a very low leakage capacitor and a very low input bias current/input impedance input on whatever its connected to. Often you can only go to a few K ohms if you're going directly into a micro. 

There is no maximum or minimum for the capacitance value, provided you keep the resistance more than 4.7K. You could use a 10uF capacitor and a 100K resistor (if whatever it's connected to is okay with 100K) and get a 0.16Hz cutoff if you want. The trade-off is that the response will be sluggish and it will take many seconds to settle to a stable value (a bit less than 5 time constants or 5 seconds in this case to get within 1% of the final value).