From Newsgroup: sci.electronics.design


https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

MTBF is only about 12 years.

I'll advise my customer against it.




John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
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From Newsgroup: sci.electronics.design

On Thu, 02 Jul 2026 07:09:57 -0700, john larkin <jl@glen--canyon.com>
wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

MTBF is only about 12 years.

I'll advise my customer against it.

Not so fast. I looked them up. It's a real company. Look at their
leaders, like CEO and Tech guy.

Joe
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From Newsgroup: sci.electronics.design

john larkin <jl@glen--canyon.com>wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

MTBF is only about 12 years.

I'll advise my customer against it.

Payed US $71,99 on ebay for this in November 2012:
FE-5680A Rubidium Atomic Frequency Standard 10MHz out
https://panteltje.nl/pub/rubidium_frequency_standard_running_IMG_3700.GIF Still works
Is a bit bigger..

Not on 24/7 only every now and then.

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From Newsgroup: sci.electronics.design

john larkin <jl@glen--canyon.com> wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

MTBF is only about 12 years.

I'll advise my customer against it.

And just mere $2,125, real bargain...

---
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* KSI@home KOI8 Net < > The impossible we do immediately. *
* Las Vegas NV, USA < > Miracles require 24-hour notice. * ******************************************************************
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From Newsgroup: sci.electronics.design

On Thu, 02 Jul 2026 15:41:41 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

john larkin <jl@glen--canyon.com>wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

MTBF is only about 12 years.

I'll advise my customer against it.

Payed US $71,99 on ebay for this in November 2012:
FE-5680A Rubidium Atomic Frequency Standard 10MHz out
https://panteltje.nl/pub/rubidium_frequency_standard_running_IMG_3700.GIF
Still works
Is a bit bigger..

Not on 24/7 only every now and then.

We have one like that, but we can't use ebay parts in products. And
we'd need something small that would mount on a PC board.

Rubidiums are power hogs too, and have roughly 10 year MTBFs.

There seem to be two common pcb-mountable units, the $2K square ones
and the $3K rectangulars. Most look identical and have the same
phrases in their data sheets. Maybe they are really the same parts, or
exact copies.

We need some new physics here. That the ribidium even works is an
amazing collection of coincidences.


John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
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From Newsgroup: sci.electronics.design

On 3/07/2026 12:09 am, john larkin wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

Note 3 on page 1 of the data sheet.

"The application should maintain thermal stability to obtain optimum performance. The use of a heat sink or copper plate under the device
should be avoided.
Device mounting should allow for a minimum of 1mm clearance from the
printed circuit board".

They do seem to want you to leave a little air space as air insulation
under the device.

MTBF is only about 12 years.

What the data sheet says is "approximate MTBF is 100,000 hours,
stationary". The schemes for calculating approximate MTBF numbers are
very approximate. There's no obvious wear-out mode, and the device will probably outlast the customers application.

I'll advise my customer against it.

You do get nervous about stuff you don't understand. What are you going
to advise them to use instead? Something based on the thorium--229
nuclear resonance?

https://en.wikipedia.org/wiki/Nuclear_clock

They may have to wait a bit before the idea is reduced to practice.
--
Bill Sloman, Sydney

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From Newsgroup: sci.electronics.design

Am 02.07.26 um 18:30 schrieb john larkin:

We have one like that, but we can't use ebay parts in products. And
we'd need something small that would mount on a PC board.

Rubidiums are power hogs too, and have roughly 10 year MTBFs.

There seem to be two common pcb-mountable units, the $2K square ones
and the $3K rectangulars. Most look identical and have the same
phrases in their data sheets. Maybe they are really the same parts, or
exact copies.

We need some new physics here. That the ribidium even works is an
amazing collection of coincidences.

some MTI 270 series crystal dual ovens invade Rubidium turf,
depending on the options. There are 2 of the 270 in my Lucent
house reference as a redundant pair. Methinks they are not the
real costly ones because they are locked to GPS anyway for good
long term trend.

Gerhard
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From Newsgroup: sci.electronics.design

On Thu, 02 Jul 2026 09:30:03 -0700, john larkin <jl@glen--canyon.com>
wrote:

On Thu, 02 Jul 2026 15:41:41 GMT, Jan Panteltje <alien@comet.invalid>
wrote:

john larkin <jl@glen--canyon.com>wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

MTBF is only about 12 years.

I'll advise my customer against it.

Payed US $71,99 on ebay for this in November 2012:
FE-5680A Rubidium Atomic Frequency Standard 10MHz out
https://panteltje.nl/pub/rubidium_frequency_standard_running_IMG_3700.GIF >>Still works
Is a bit bigger..

Not on 24/7 only every now and then.

We have one like that, but we can't use ebay parts in products. And
we'd need something small that would mount on a PC board.

Rubidiums are power hogs too, and have roughly 10 year MTBFs.

Yes. The MTBF is dominated by the physics package. The Rubidium is
slowly absorbed into the fused quartz bulb inner wall material where
the physics is done.

There seem to be two common pcb-mountable units, the $2K square ones
and the $3K rectangulars. Most look identical and have the same
phrases in their data sheets. Maybe they are really the same parts, or
exact copies.

Physics package will be the same, and the stuff around will be
optimized for this or that.

We need some new physics here. That the ribidium even works is an
amazing collection of coincidences.

It seems that what you need is CSAC (Chip Scale Atomic Clock) which
actually uses Cesium, but has Rb-level stability. Costs about $2900.

.<https://www.microchip.com/en-us/product/CSAC-SA65>

What are the requirements and use case?

Joe
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From Newsgroup: sci.electronics.design

John Larkin <jl@Glen--Canyon.com> wrote:
|--------------------------------|
|"We need some new physics here."|
|--------------------------------|

Why?
(S. HTTP://Gloucester.Insomnia247.NL/ fuer Kontaktdaten!)
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Thu, 2 Jul 2026 20:34:24 -0000 (UTC), C<il0n Nioclbs0n Glostoir <thanks-to@Taf.com> wrote:

John Larkin <jl@Glen--Canyon.com> wrote:
|--------------------------------|
|"We need some new physics here."|
|--------------------------------|

Why?
(S. HTTP://Gloucester.Insomnia247.NL/ fuer Kontaktdaten!)

Because rubidiums are big power hogs and have limited lifetimes. And
are expensive.


John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- Synchronet 3.22a-Linux NewsLink 1.2

From Newsgroup: sci.electronics.design

On Fri, 3 Jul 2026 02:44:02 +1000, Bill Sloman <bill.sloman@ieee.org>
wrote:

On 3/07/2026 12:09 am, john larkin wrote:

https://www.digikey.com/en/products/detail/abracon-llc/AR50LC-10-000MHZ-CBA/22540120

It almost mounts on my PCB.... with its power supply.

They say to space it off the PCB for some reason.

Note 3 on page 1 of the data sheet.

"The application should maintain thermal stability to obtain optimum >performance. The use of a heat sink or copper plate under the device
should be avoided.
Device mounting should allow for a minimum of 1mm clearance from the
printed circuit board".

They do seem to want you to leave a little air space as air insulation
under the device.

MTBF is only about 12 years.

What the data sheet says is "approximate MTBF is 100,000 hours,
stationary". The schemes for calculating approximate MTBF numbers are
very approximate. There's no obvious wear-out mode, and the device will >probably outlast the customers application.

The physics package, a rubidium lamp and a separate quartz tube full
of vaporized rubidium, tends to fail.

Caesium clocks just run out of caesium.

I'll advise my customer against it.

You do get nervous about stuff you don't understand.

I understand it and I'm not nervous. I actually have a rubidium clock,
and its schematic. It's clever and depends on a lot of luck, some
physics and some numerical accidents.

What are you going

to advise them to use instead? Something based on the thorium--229
nuclear resonance?

A $5 TCXO.


John Larkin
Highland Tech Glen Canyon Design Center
Lunatic Fringe Electronics
--- Synchronet 3.22a-Linux NewsLink 1.2