[time-nuts] WWVB PM Time Questions

[Bob kb8tq]

Hi

> On Jul 30, 2020, at 5:11 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> 
> 
>> I'm sure there are a lot of transistors in their IC to handle all the phase
>> tracking and time decoding.
> 
> They aren't doing phase tracking, just decoding time data.  All that crap 
> about Atomic Time is just advertising BS.
> 
> Moore's Law applies to transistors.  It doesn't matter if you use them for 
> analog or digital.
> 
> There is a wonderful concept: Pad Limited.  

How about “dicing limited” ? 

Turns out that your silicon wafer always needs to be chopped into pieces. That’s a messy
mechanical process. It really hasn’t changed a lot over decades. A die that’s 1 mm  on a 
side is about the smallest economical part. Go smaller and you “saw cut” simply is throwing
away more silicon ….

Bob


> Suppose your design takes N pads 
> for bond wires to the outside world.  Start with the logic for your design.  
> Squish it down to a sensible shape.  Now put the pads around it.  Pads are big 
> (relative to transistors).  If they bump into each other, you may have empty 
> room left over inside the pad ring.  In a mature process, the yield is close 
> to 100% and doesn't depend on how many transistors you put in that empty space 
> so you might as well use it.
> 
> If you don't have empty room today, wait a bit.  Transistors are shrinking 
> faster than pads.
> 
> Watches are the classic example.  They have lots of pads because each segment 
> on the display needs its own wire.  So you get watches that can keep track of 
> days of the month and know about leap years.
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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