[time-nuts] 4046 replacement

Richard (Rick) Karlquist richard at karlquist.com
Wed Apr 18 12:07:11 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



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