[TriEmbed] This hertz to read - why is 32768 Hz the perfect frequency?

[John Wettroth]

Boy- that looks like it was written by Chat GPT or something- what a word salad!
 
Maxim/Dallas, my old employer was instrumental in this market.  Maxim’s genealogy springs from Intersil, who along with Epson/Seiko invented all this stuff in the 70’s.  32768 is kind of a magic frequency- though you can make tuning fork crystals at lower frequencies down to 10 KHz, they are more expensive and if you go much higher, you start to dissipate power more power (C x V x F)  You also want something high enough so you can tune it, 1 part in 32768 is about 30 ppm, which is about a minute per month.  You can tune this in a few seconds during final test- it takes a second to accumulate the counts required.  32768 crystals are one of the highest volume components made- several billion per year.
 
One of the ways to make really accurate crystal oscillator is to ovenize the oscillator.  They run at 50 or 75C, way above ambient generally and the tempco goes away- only problem is they draw a bunch of power.  Maxim/Dallas took a different approach and made parts that run at room but have a temp sensor and a look up table and correction stuff to get to 1 ppm on 1 uA of Icc.  The DS3231 is the flagship from 15 years ago and has been copied and cloned mercilessly.  These parts were driven by the need of gas and water meter guys who needed clocks that could keep time to a few seconds a year for billing.
 
One of the cool things about wrist watches and crystals is since there on your arm, they are “ovenized” in a way at 98.6 degrees and can run very accurately.
 
My late night 2 cents.
Regards,
John M. Wettroth
E: jwet at mindspring.com
M: (919) 349-9875 
H:  (984) 329-5420
 
From: TriEmbed <triembed-bounces at triembed.org> On Behalf Of R Radford via TriEmbed
Sent: Thursday, March 30, 2023 10:26 PM
To: TriEmbed Discussion <triembed at triembed.org>
Subject: [TriEmbed] This hertz to read - why is 32768 Hz the perfect frequency?
 
I learned a lot of new facts from this I have never seen in any other location before - amazing article.
 
Why is 32768 Hz the perfect frequency? (chinachipsun.com) <https://www.chinachipsun.com/32768-hz/> 
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