I'm currently designing a phase locked loop using a CD4046, MY FMIN is 250kHz and FMAX is 500kHZ, centre frequency 375kHz. I need to know how to calculate the components for the LPF.
I know that f=1/(2pi*RC), but what considerations do I take?
Thank you in advance for any help with this problem
The data sheet for the particular 4046 you're usign will have a couple of graphs etc. which help you pick the values.
I find these are only a general starting point, once youve picked the parts (from the data sheet graphs), find out what frequency the pll locks at then tweak away until you get the desired centre frequency and range.
thanks for your reply, I've determined the parts for r2,r1 and c and i've built the circuit. My problem is the loop filter. do i calculate the values of the filter to give the bandwidth e.g f=1/(2pi*CR)?
I've read loads of stuff and none of it seems to make sense? I must be getting dumber the older I get