How to know what is the minimum capture range of CD74HCT7046A PLL chip

I need to know how to design the low pass filter whose output is then pass on to the VCO input of the CD74HCT7046A PLL chip. By determining the values for the resistor R3 and R4 & capacitor C2. i can also be able to determine the capture range. the required capture range for my project is 1-2Hz with a center frequency of 50Hz (AC line frequency). it is important for me to know whether is this usable or not (if not please recommend a PLL chip that is suitable for my project). i am using this datasheet   6663.74hc7046a.pdf    as a reference. thank you in advance for helping me.