MEMS relays are back!...

J

John Larkin

Guest
https://menlomicro.com/

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
 
On Wednesday, 11 May 2022 at 00:10:19 UTC+1, John Larkin wrote:
> https://menlomicro.com/

I looked at the data for the MM1200 – 6 Channel SPST Micro Relay
There do seem to be a lot of restrictions relating to hot switching and
floating nodes. The description \"ideal switch\" is perhaps going a bit far.
John
 
On Wednesday, May 11, 2022 at 5:01:36 AM UTC-4, John Walliker wrote:
On Wednesday, 11 May 2022 at 00:10:19 UTC+1, John Larkin wrote:
https://menlomicro.com/

I looked at the data for the MM1200 – 6 Channel SPST Micro Relay
There do seem to be a lot of restrictions relating to hot switching and
floating nodes. The description \"ideal switch\" is perhaps going a bit far..

One issue I would be concerned about is the fact that it actually consists of many relays connected in parallel. When they are opened, they can not be opened simultaneously, but rather open sequentially, even if very close together in time. This would tend to concentrate the current flowing until the last relay contact is opened, with all the current flowing through that one contact. I suppose this is limited by parasitic inductance and the consistency in timing of the contacts opening. If they all open at the same time to within a nanosecond, then I don\'t see much problem.

I suppose this issue is reflected in the life rating which is pretty good, at 3 billion operations, so not really a problem.

--

Rick C.

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John Larkin wrote:

> https://menlomicro.com/

I would find a lot of applications for those operating in the sub-mA/3V
range. Purchasable or \"I had a dream\" Silicon Valley startup vapourware?

Best regards, Piotr
 
On Wed, 11 May 2022 20:49:50 +0200, Piotr Wyderski
<bombald@protonmail.com> wrote:

John Larkin wrote:

https://menlomicro.com/

I would find a lot of applications for those operating in the sub-mA/3V
range. Purchasable or \"I had a dream\" Silicon Valley startup vapourware?

Best regards, Piotr

A lot of MEMS relay companies have arrived with great expectations and
then quietly died. I\'ll wait for Digikey to have parts, and try some.

MEMS seem OK for resonators and accelerometers, but contacts seem to
have welding/sticking issues.

Here\'s another one:

https://atomica.com/

Seems like they could make interesting filters, like the old Collins
mechanical filters.

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
 
John Larkin wrote:

A lot of MEMS relay companies have arrived with great expectations and
then quietly died. I\'ll wait for Digikey to have parts, and try some.

So will I. One remark about the 6 SPST BGA: they require +79V external
supply. Without reading the datasheet, I guess it is an electrostatic
relay, not magnetic. Quite interesting, but wait... they can make a MEMS
relay and fail to make a built-in charge pump?

Best regards, Piotr
 
John Walliker wrote:
On Wednesday, 11 May 2022 at 00:10:19 UTC+1, John Larkin wrote:
https://menlomicro.com/

I looked at the data for the MM1200 – 6 Channel SPST Micro Relay
There do seem to be a lot of restrictions relating to hot switching and
floating nodes. The description \"ideal switch\" is perhaps going a bit far.
John

That website smells of dotcom.

The main issues with MEMS switches are materials (good materials for
MEMS fabrication generally aren\'t great electrically and mechanically)
and the tendency of the contacts to weld or vaporize under fairly mild
abuse, because they don\'t have a lot of mass to take the heat.

If the Menlo folks have figured out how to fix those things, I\'m all for it.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com
 
On 11/05/2022 23:59, Ricky wrote:
On Wednesday, May 11, 2022 at 5:01:36 AM UTC-4, John Walliker wrote:
On Wednesday, 11 May 2022 at 00:10:19 UTC+1, John Larkin wrote:
https://menlomicro.com/

I looked at the data for the MM1200 – 6 Channel SPST Micro Relay
There do seem to be a lot of restrictions relating to hot switching and
floating nodes. The description \"ideal switch\" is perhaps going a bit far.

One issue I would be concerned about is the fact that it actually consists of many relays connected in parallel. When they are opened, they can not be opened simultaneously, but rather open sequentially, even if very close together in time. This would tend to concentrate the current flowing until the last relay contact is opened, with all the current flowing through that one contact. I suppose this is limited by parasitic inductance and the consistency in timing of the contacts opening. If they all open at the same time to within a nanosecond, then I don\'t see much problem.

Did you miss the part about where you have to turn off the current
through the contacts before you are allowed to switch the MEMS relay? In
their power relay they use a parallel MOSFET to do this. Given that the
MEMS relay has not that great on-resistance, you could probably leave
that bit out, and just use the MOSFET. In the RF relay, there is no
MOSFET so you have to turn off the RF power yourself, e.g. set
modulation of the signal such that the carrier goes away, then you can
switch it.
 
On 12/05/2022 05:16, Piotr Wyderski wrote:
John Larkin wrote:

A lot of MEMS relay companies have arrived with great expectations and
then quietly died. I\'ll wait for Digikey to have parts, and try some.

So will I. One remark about the 6 SPST BGA: they require +79V external
supply.

Amusingly, 79V, not 77V and not 81V. Perhaps they only test it at one
voltage and so don\'t know whether the parts work at other voltages.
 
On Thu, 12 May 2022 22:21:45 +1000, Chris Jones
<lugnut808@spam.yahoo.com> wrote:

On 12/05/2022 05:16, Piotr Wyderski wrote:
John Larkin wrote:

A lot of MEMS relay companies have arrived with great expectations and
then quietly died. I\'ll wait for Digikey to have parts, and try some.

So will I. One remark about the 6 SPST BGA: they require +79V external
supply.

Amusingly, 79V, not 77V and not 81V. Perhaps they only test it at one
voltage and so don\'t know whether the parts work at other voltages.

Or worse, maybe it really cares.



--

Anybody can count to one.

- Robert Widlar
 
jlarkin@highlandsniptechnology.com wrote:

Amusingly, 79V, not 77V and not 81V. Perhaps they only test it at one
voltage and so don\'t know whether the parts work at other voltages.


Or worse, maybe it really cares.

It likely does:

https://menlomicro.com/images/general/Menlo_MM1200_Preliminary_Datasheet_Rev1.2.pdf

78V min, 80V max. This accuracy requirement calls for a built-in boost
converter even stronger. It is not exactly trivial (in terms of part
count and board space) to provide such a power rail.

Best regards, Piotr
 
On Fri, 13 May 2022 10:40:14 +0200, Piotr Wyderski
<bombald@protonmail.com> wrote:

jlarkin@highlandsniptechnology.com wrote:

Amusingly, 79V, not 77V and not 81V. Perhaps they only test it at one
voltage and so don\'t know whether the parts work at other voltages.


Or worse, maybe it really cares.

It likely does:

https://menlomicro.com/images/general/Menlo_MM1200_Preliminary_Datasheet_Rev1.2.pdf

78V min, 80V max. This accuracy requirement calls for a built-in boost
converter even stronger. It is not exactly trivial (in terms of part
count and board space) to provide such a power rail.

Best regards, Piotr

That tolerance makes the gadget sound really flakey. As mems relays
have historically been.





--

Anybody can count to one.

- Robert Widlar
 
jlarkin@highlandsniptechnology.com wrote:

That tolerance makes the gadget sound really flakey. As mems relays
have historically been.

This one appears to exist:

https://www.analog.com/media/en/technical-documentation/data-sheets/adgm1304.pdf

And it has the charge pump. But just 7.2 years of continuous on lifetime?!

Best regards, Piotr
 
On Wed, 18 May 2022 23:24:06 +0200, Piotr Wyderski
<bombald@protonmail.com> wrote:

jlarkin@highlandsniptechnology.com wrote:

That tolerance makes the gadget sound really flakey. As mems relays
have historically been.

This one appears to exist:

https://www.analog.com/media/en/technical-documentation/data-sheets/adgm1304.pdf

And it has the charge pump. But just 7.2 years of continuous on lifetime?!

Best regards, Piotr

What a horrible part!

--

If a man will begin with certainties, he shall end with doubts,
but if he will be content to begin with doubts he shall end in certainties.
Francis Bacon
 

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