[time-nuts] 4046 variations (was EPE GPS....)

Javier Herrero jherrero at hvsistemas.es
Sun Sep 27 16:54:36 UTC 2009

Yes, of course, some applications needs the parts that are in the better 
side of the distribution curve for a particular parameter and for a 
particularly stringent application, as you mention :), but I think that 
a 4046 seems a part that should not have to be so critical that even in 
the same lot number some work, some don't, and it is hard to believe 
that no alternatives existed on that time that could have avoided the 
high costly selection process.



Lux, Jim (337C) escribió:
> On 9/27/09 7:22 AM, "Javier Herrero" <jherrero at hvsistemas.es> wrote:
>> Margina design? ;) Better said, very poor design.
>> Does not sound very good that same part, same lot code, sometimes work
>> here but not there, sometimes does not work at all... Extending it a
>> bit... sometimes will work at a given temperature, sometimes will not at
>> a given other.
>> Regards,
>> Javier
>> Robert Atkinson escribió:
>>> The old King Radio (then Bendix-King now part of Honeywell) Silver crown
>>> aircraft radios used 4046's in some of the synthesisers.
> Not always marginal or poor design.  Sometimes, you can't get the
> performance needed with (any) part that simply meets the datasheet specs, so
> hand selection is needed.  Picking matched pairs is a time honored method
> for instance.. In some cases, the mfr does the picking for you (RF power
> transistors). In another case, there's an extremely low noise FET used in
> some charge amplifiers that not only has to come from one mfr
> (notwithstanding the 2N JEDEC number) but you want to buy a bunch and pick
> the quietest one.  High value resistors and leakage currents also come to
> mind.
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Javier Herrero                            EMAIL: jherrero at hvsistemas.com
HV Sistemas S.L.                          PHONE:         +34 949 336 806
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