[time-nuts] Re: Power and heat re: Heathkit WWV clock / where are the good oscillators?

[Hal Murray]

> I don't follow. Are you saying that CMOS is obsolete and was succeeded by
> something else? What's the connection to the Heathkit? It didn't have CMOS
> chips as far as I know.

The connection to the Heathkit is that you were asking why it used so much 
power.

Modern CMOS processing is fantastic.  It is used for both high performance 
CPUs and power stingy battery operated gear.

With CMOS, if you ignore leakage, power is proportional to speed.  You are 
just charging and discharging capacitors.

Bleeding edge high performance CMOS CPUs have very very thin oxide layers.  
They run real fast.  They also leak like a sieve.  Forget batteries.

For things like cell phones, there is a trade off between peak performance and 
battery life.

There is a lot of interest in small micro processors for battery operations.  
The classic example is the remote for your TV.

For things like watches, they don't care about performance so they can go 
crazy in the low leakage direction.

One thing to watch out for...  Leakage is strongly temperature dependent.  The 
data sheet typical at 25C doesn't mean anything if your application will run 
warmer than that.



-- 
These are my opinions.  I hate spam.