[time-nuts] 4046 replacement

Steve Wilson sw at silverwin.e4ward.com
Wed Apr 18 21:55:14 EDT 2018


>On 4/18/2018 4:34 AM, John Miles wrote:

>> Ulrich Rohde's book indicates that this problem was first documented in 1978 in an EDN article by some authors named Egan and Clark.  Newer PFDs implement the 'antibacklash' logic that Rohde mentions.  If you really must use a 4046, I'd look for a newer version whose data sheet explicitly addresses this problem.  Better still, use a newer part.

>The book is incorrect.  A patent issued in 1976 (US4023116A)
>covering the Fairchild 11C44 developed by Eric Breeze predates
>the EDN article by several years.  I still remember the big
>splash the 11C44 made when it was introduced in 1976. The Fairchild
>ECL data book had a famous graph comparing it to the MC4044
>in the dead zone.  In those days, Fairchild and Motorola
>were going head to head.  I worked on a synthesizer in 1975
>that used their brand new at the time 11C90 prescaler.

>You can still get 11C44's of a sort by ordering NTE974's
>that claim to be a replacement.

>Rick N6RK

I filed patent 3,810,234 on Aug 21, 1972. It includes a dual-d pfd with
variable delay in the feedback path to eliminate deadband. The term
deadband is not included in the patent since it did not exist at the time.
The google url is

https://patentimages.storage.googleapis.com/53/fc/f0/26d83e477e999a/US3810234.pdf

The dual-d is items 24 and 26 on page 4. The feedback is item 58, and the
variable delay is item 28 on the same page. It turns out the delay was not
needed in production since there was no deadband when it was shorted out.

I recall finding an article on the dual-d pfd that was earlier than my
patent but I forget where I found it.

Ignore the name Steve Wilson. That is my online name to foil id theft and
malware.

Mike Monett


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