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cd4046 with input square wave

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maame

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Hi,

I have been trying to design a pll to multiply square wave corresponding to a frequency of about 1.2 Hz using cd4046 by 12. I've not built it yet but I want to know if CD4046 can synthesize such low frequency and if it can work on square wave input.

Second, does the cd4046 have a minimum lock time?

third, the input to the pll is from a comparator. what i mean is the square waves were formed by an opamp comparator. Does this pose a problem for my design?

Thanks.
 

There's no lower frequency limit by 4046 specification. Lock time is ruled by general PLL theory, in practice it depends
on initial VCO frequency, utilized phase detector, loop gain, filter characteristic.

Both 4046 phase detectors have digital inputs, they can work with any input signal keeping the CMOS level specification. An OP or
comparator using the same supply as the 4046 should work in most cases.
 

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    maame

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