Preface
I need to use a phase locked loop to lock onto a signal that can vary from 30Hz to 65 Hz and want to implement it digitally. After some general research I found that Zero crossing phase locked loops were relatively easy to implement in software. So i decided to use this type of PLL.
Question
I was trying to work out how to implement my loop filter and came across these notes on component selection http://www.ti.com/lit/an/snaa015b/snaa015b.pdf. Though these say obsolete at the top, does this mean that the charge pump pll has been superseded by another type of pll?
Me asking you to do my work for me If you know, could you recommend to me what type of PLL i should be using?
Best Answer
The biggest cause of parts becoming "obsolete" was the move to lead free requirements under the ROHS directive. In those cases there is usually a direct replacement, but with a modified part number.