On Mon, 22 Oct 2012 20:08:24 +0100, Mike Perkins
wrote:
On 22/10/2012 16:42, Jim Thompson wrote:
Quite frankly I don't give a rat's ass whether you use the model or
not. I find the 74HC4046 a piece-a-crap, a rather poor CMOS copy of
my original design, the quite linear MC4024 of nearly 50 years ago.
...Jim Thompson
I have found that the variation of parameters the 74HC4046 from one
manufacturer to another is such that I cannot agree with such a sweeping
statement. I found the Philips/NXP variant a very well behaved device,
whereas others had/have poor VCO control linearity etc.
I'm just going from reports here, primarily Phil Hobbs' bad
experiences. ALL of the data sheets look wonderful ;-)
I can certainly think of ways to improve it, particularly the current
mirrors, though a complete architecture change could easily eliminate
lots of the non-linearity issues.
Whoever rolled the CMOS copy totally missed an important point, don't
dump the capacitor into a substrate diode.
...Jim Thompson
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