Has anyone ever used a chip-scale atomic clock? - Page 1
Forum section: electronics / general

author: technix
author_rank: Super Contributor
timestamp: December 17, 2018, 07:40:27 am
content: Something like this:https://www.microsemi.com/product-directory/clocks-frequency-references/3824-chip-scale-atomic-clock-csacIt seem to me that this is a good option, if not very expensive, for an atomic wristwatch. It also supports PPS input for trimming so maybe combine that with a GPS module, hopefully one that can take that 10MHz input as a reference clock, for even more accuracy?

author: ataradov
author_rank: Super Contributor
timestamp: December 17, 2018, 07:54:21 am
content: DigiKey shows a price of $5312Also, "chip scale" is a relative term, apparently, since this thing is still huge and weights 35 grams.

author: DaJMasta
author_rank: Super Contributor
timestamp: December 17, 2018, 08:08:00 am
content: Jackson Labs makes some CSACs, probably cheaper than that, but maybe not by much - no prices listed.While you can probably get one small enough to be a chubby watch........... it's going to take a Watt or two to run, so how do you plan on getting a battery big enough for lasting past warm up in a watch?I think the practical answer for an atomic clock in a watch is a gps receiver.

author: dzseki
author_rank: Frequent Contributor
timestamp: December 17, 2018, 08:10:11 am
content: Quote from: ataradov on December 17, 2018, 07:54:21 amA decent Rolex is much more expensive

author: Kleinstein
author_rank: Super Contributor
timestamp: December 17, 2018, 08:51:30 am
content: Quote from: DaJMasta on December 17, 2018, 08:08:00 amThe MIrosemi version is supposed to run at 120 mW. Still a little high on the wrist.

author: Rerouter
author_rank: Super Contributor
timestamp: December 17, 2018, 09:35:18 am
content: 120mW, perfect watch for colder climateshas a built in defrost function

author: timgiles
author_rank: Regular Contributor
timestamp: December 17, 2018, 11:31:21 am
content: Its amazing to see the size of the module, but for a watch, its 11.4mm high, 40.6mm x 35.3 - it still seems a little big for a watch. You would need a reasonable battery, then some PCB / Flex for driving a clock face, interface with the module etc... Just seems still to be too big to me. But - as a portable high precision clock - I am sure there are some that would find it useful and would have the money for it.Seems to be a little sensitive to magentic fields, but I dont have any idea how much Magnetic sensitivity (≤2.0 Gauss) ±9 × 10–11/Gauss actually is in day to day use for this type of device.

author: ap
author_rank: Frequent Contributor
timestamp: December 17, 2018, 02:19:01 pm
content: A small size rubidium osc from Microsemi is much lower price (SA.31m ..., arround 1400)

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: December 17, 2018, 03:27:50 pm
content: ...and Jackson Labs is just strange... No prices posted on their website. If you send an inquiry you get a price quote back in your email. If you inquire about shipping you are told they do not ship GROUND.Reason: Fedex tends to abuse(drop) ground packages more.They do accept Credit Card payments, HOWEVER they have something like a 2% surcharge for it, or you can send them a check, and when it clears the bank, they will ship it 3 day, 2 day, 1 day etc. via Fedex.I just find this strange business practices.

author: retroware
author_rank: Contributor
timestamp: December 17, 2018, 05:52:32 pm
content: Someone actually did make a watch out of the microsemi part:https://www.hodinkee.com/articles/introducing-the-bathys-cesium-133-atomic-clock-watchCalling it a wristwatch seems a bit of a stretch

author: GregDunn
author_rank: Frequent Contributor
timestamp: December 17, 2018, 06:41:41 pm
content: Wouldn't you need at least a 10-1/2 digit digital display to do justice to the accuracy of 1 second in 1000 years?

author: Kleinstein
author_rank: Super Contributor
timestamp: December 17, 2018, 08:14:23 pm
content: Such a clock chip does not make sense for a watch. It is more suitable for something like a high grade counter or generator. Some measurements that need to precisely timed, but have not GPS reception (e.g. underwater seismic detector) would be another application.

author: LapTop006
author_rank: Unknown
timestamp: December 18, 2018, 05:18:36 am
content: Quote from: ap on December 17, 2018, 02:19:01 pmBroadly, the CSAC isn't quite as good as the larger Rubidium packages, so the only reason to use it is if you can't use a GPSDO and want a tiny form factor.There are plenty of those use cases, but not all that many, for example theOBSIP use them in undersea loggers.