[time-nuts] 74HCT9046A Max. Operating Frequency

wb6bnq wb6bnq at cox.net
Thu Apr 24 07:18:05 EDT 2014

Hello Samuel,

Well, I just got done designing and building the very same thing.  If I 
recall correctly it is the same as the HC4046 which is 4 MHz.  The 9046 
VCO will only go up to 20 MHz absolute maximum.  So you will need an 
external oscillator and dividers.


sg sg wrote:

>I'm about to implement a PLL for a 24.576 MHz VCXO using the phase-frequency detector (PC2) of the NXP 74HCT9046A. From the datasheet (www.nxp.com/documents/data_sheet/74HCT9046A.pdf) it is not clear to me what the maximum operating frequency for this phase detector is--from the enable and disable times (page 20 and figure 19) I presume 24.576 MHz is too much.
>So I probably need to add dividers at the inputs. Can someone advise me on the choice of division ratio?
>Thanks for your time,
>time-nuts mailing list -- time-nuts at febo.com
>To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>and follow the instructions there.

More information about the time-nuts mailing list