Other Parts Discussed in Thread: LMC555
Dear Forum Member,
I am interested in the (analog) phase locked loops (Signetics older NE56x series and their descants).
I would like to know whether CMOS 567 internally use a classic Gilbert cell (aka balanced mixer, a combination of 3 differental pairs) for implementing its detectors or other alternative solution.
For example:
using analouge switche: signal is switched by 0deg VCO signal and its the inverted (180deg) form is switched by 180 deg VCO signal and switch outputs combined then converted to current (note, LMC567 Phase and Lock detector has current output according to datasheet block diagram and biased for certain voltage levels (0,67VDD etc) by resistor string between VDD and VSS).
I assume the LMC567 VCO is based on the LMC555 circuit. I do not know whether it is corrent.
I would have an other question: why the LMC568 has been obsolete? It was a true linear (general purpose) device (with linear VCO V-f characteristics, allowing to be a replacement for the popular NE/LM565 for instance).
Thank you for the response in advance.
Regards,
Joseph
