[time-nuts] The ultraAtomic clock for home

[Bob kb8tq]

Hi

> On Apr 7, 2017, at 7:19 PM, jimlux <jimlux at earthlink.net> wrote:
> 
> On 4/7/17 3:45 PM, Charles Steinmetz wrote:
>> Bob wrote:
>> 
>>> The epoxy over wire bond construction approach
>>> is low cost, and not very experimenter friendly.
>> 
>> It is also extremely unreliable, particularly WRT environmental effects
>> such as temperature changes, humidity, and atmospheric pollutants.  In
>> my view, it is unsuitable for use in anything but dirt cheap, purely
>> disposable devices like greeting-card audio players and disposable cameras.
>> 
> 
> Interestingly enough it *is* used in space flight hardware.

Humidity does not tend to be a big issue once you get in space :)

Bob

>  It is much less expensive, lighter weight and easier to inspect than thick film hybrids and similar schemes.
> 
> You can can do a pre-cap inspection, then apply the potting material, and then you could even xray it to see if the bond wires moved or something.
> 
> A flipchip with a blob is even better.
> 
> It's even reworkable (e.g. you can soften the blob & solder and scrape the die off and bond a new one down).
> 
> I suspect that there is a wide variation in the material you blob on there and so forth.
> 
> 
> 
> 
> 
> 
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