Esata - Sata query

In message , Bill in Co
writes:
Paul wrote:
Bill in Co wrote:

That is one weird looking connector. It will be interesting to see if

I think the one on my Portégé laptop is the one shown above the one
labelled laptop.

this ever becomes mainstream. I think I'd prefer separate connectors,
but maybe I'm being conservative and old fashioned. I think the eSata

You are not alone, whatever!

ones were a bit (slightly) flimsy at it is, however.

The original ESATA intention was metal to metal contact
and a 5000 cycle rating. The same rating as USB metal connectors.

The internal SATA connector system, is plastic and
the rating is 50 cycles. Although my tests in the
Test machine (swapping drives all the time), is now
many times over that figure. Those connector ratings
are probably a "guaranteed minimum", but I don't know
what "mis-mated" conditions they apply to test that
out.

The usage of metal barrels or surfaces for capture,
makes a big difference to the spec number.

Paul

In retrospect, I misspoke, and was thinking of the SATA connector found on
the internal SATA drive, which I thought was a bit flimsy. The eSATA
connector on the end of the cable I've got looks rugged enough. Sorry!


I remember back in the days of 25-way D connectors and the DIN 41612
family, there were three classes (I can't remember whether class 1 or 3
was best), which were mainly to do with how much gold plating was on the
pins, rather than mechanical type of wear. The cheapest - about 50p for
a D-25 - was "gold flashing", i. e. there was gold there, but really
only to protect the pins from corrosion in storage while they were
waiting to be assembled onto something and used; they were really
intended for things that were plugged in and left in place, and rated at
something like 3 to 5 insertions. Class 2 was IIRR about 0.5 to 1 micron
of gold, and intended for things like circuit cards that would be
replaced or moved around from time to time, and rated for a few tens of
insertions. The most expensive - about 5 pounds for a D-25 - were 5
microns gold, intended for things being reconnected often; I think they
were at a few hundred insertions.

(For D types, there was also whether the pins were "formed" - made out
of thin sheet brass, thus hollow [these worked better than you'd
expect!], or "turned".)

I don't _remember_ anything about the plastic housings having different
number-of-mating-cycles qualities.
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)[email protected]+H+Sh0!:`)DNAf

The first banjo solo I played was actually just a series of mistakes. In fact
it was all the mistakes I knew at the time. - Tim Dowling, RT2015/6/20-26

J. P. Gilliver (John) wrote:

I remember back in the days of 25-way D connectors and the DIN 41612
family, there were three classes (I can't remember whether class 1 or 3
was best), which were mainly to do with how much gold plating was on the
pins, rather than mechanical type of wear. The cheapest - about 50p for
a D-25 - was "gold flashing", i. e. there was gold there, but really
only to protect the pins from corrosion in storage while they were
waiting to be assembled onto something and used; they were really
intended for things that were plugged in and left in place, and rated at
something like 3 to 5 insertions. Class 2 was IIRR about 0.5 to 1 micron
of gold, and intended for things like circuit cards that would be
replaced or moved around from time to time, and rated for a few tens of
insertions. The most expensive - about 5 pounds for a D-25 - were 5
microns gold, intended for things being reconnected often; I think they
were at a few hundred insertions.

(For D types, there was also whether the pins were "formed" - made out
of thin sheet brass, thus hollow [these worked better than you'd
expect!], or "turned".)

I don't _remember_ anything about the plastic housings having different
number-of-mating-cycles qualities.

It's where metal shells meet and provide "capture" that
counts. A D-series connector usually has a metallic "shield"
surface, which also doubles as a capture shell. With
a slightly turned edge so it doesn't snag perhaps.

Once two connector pieces are "docked", that takes
some of the side-wards play out of mating. Then, it's
a matter of how the pins and contact surfaces on the
mate interact, as to how long the contacts hold up
to repeated insertion. On some connectors, they use
a surface lubricant to increase cycle life. Some IDE
ribbons were using that on their pins, and you can
tell when the lube has left the scene, as the insertion
force increases. If the insertion force becomes too high,
that's when the pins on the male tend to get smushed
over at 90 degrees to the intended direction.

It was some older Dsub designs, where the brass pins
used to get "pushed backwards" into the shell, because
the pins weren't held very securely. Those were most
annoying. I haven't had anything like that happen in years.

Paul

J. P. Gilliver (John) wrote:
In message , Bill in Co
writes:
Paul wrote:
Bill in Co wrote:

That is one weird looking connector. It will be interesting to see if

I think the one on my Portégé laptop is the one shown above the one
labelled laptop.

this ever becomes mainstream. I think I'd prefer separate connectors,
but maybe I'm being conservative and old fashioned. I think the eSata

You are not alone, whatever!

ones were a bit (slightly) flimsy at it is, however.

The original ESATA intention was metal to metal contact
and a 5000 cycle rating. The same rating as USB metal connectors.

The internal SATA connector system, is plastic and
the rating is 50 cycles. Although my tests in the
Test machine (swapping drives all the time), is now
many times over that figure. Those connector ratings
are probably a "guaranteed minimum", but I don't know
what "mis-mated" conditions they apply to test that
out.

The usage of metal barrels or surfaces for capture,
makes a big difference to the spec number.

Paul

In retrospect, I misspoke, and was thinking of the SATA connector found
on the internal SATA drive, which I thought was a bit flimsy. The eSATA
connector on the end of the cable I've got looks rugged enough. Sorry!


I remember back in the days of 25-way D connectors and the DIN 41612
family, there were three classes (I can't remember whether class 1 or 3
was best), which were mainly to do with how much gold plating was on the
pins, rather than mechanical type of wear. The cheapest - about 50p for
a D-25 - was "gold flashing", i. e. there was gold there, but really
only to protect the pins from corrosion in storage while they were
waiting to be assembled onto something and used; they were really
intended for things that were plugged in and left in place, and rated at
something like 3 to 5 insertions. Class 2 was IIRR about 0.5 to 1 micron
of gold, and intended for things like circuit cards that would be
replaced or moved around from time to time, and rated for a few tens of
insertions. The most expensive - about 5 pounds for a D-25 - were 5
microns gold, intended for things being reconnected often; I think they
were at a few hundred insertions.

(For D types, there was also whether the pins were "formed" - made out
of thin sheet brass, thus hollow [these worked better than you'd
expect!], or "turned".)

I don't _remember_ anything about the plastic housings having different
number-of-mating-cycles qualities.

It never even occurred to me that the depth of the gold plating was such a
controlled quantity in terms of those classes and the number of "rated
insertions". Or that the lightest coating was only intended to protect
against corrosion while in storage, and only while in storage, and nothing
more. Interesting.

Bill in Co wrote:


It never even occurred to me that the depth of the gold plating was such a
controlled quantity in terms of those classes and the number of "rated
insertions". Or that the lightest coating was only intended to protect
against corrosion while in storage, and only while in storage, and nothing
more. Interesting.

In Telecom, it's 50 microns. A typical product life might be defined as "20 years".

In Computers, it's 10 microns. And presumably a shorter product life target.

One method of application is plate-up, which uses a series
of metals of appropriate metallurgy. Maybe copper followed
by nickel followed by gold. I've never been exposed to the design
details of such at work, so can't give a rationale for every
choice made there.

The other way of applying gold to something, is sputtering.
We had a sputtering setup in the Physics Department in university,
and the students used to make "gold sunglasses". The setup had
an interferometer, and you could count "wavelengths" as a measure
of the amount of gold applied. So instead of microns, it might
be some smaller number. I never made any sunglasses, so I
couldn't tell you how many wavelengths of visible light
were needed for a gold tinted sunglass lens. But the other
students got a kick out of this. Because they were making
Tom Cruise sunglasses.

In Telecom, one of the tests is "Corrosive Gas Mixtures",
where the equipment is exposed to hydrogen sulfide or
HCL gas or some other awful substance. Presumably some of those
connector design choices, are based on being able to pass
such tests. (This ensures that the most polluted urban
centers in the world, do not destroy telecom equipment.)

I couldn't tell you how Gold holds up to sliding contact
and repeated insertions - like what a typical number is for
matings. Versus say, tin on tin.

Tin on tin works by "biting" and making a gas-tight
metal to metal contact. It's not recommended to mix
the two metals (tin and gold), since they "work" by
different principles. You couldn't get the oxide off the
tin, if gold slid past it. It's gold on gold, or tin on tin,
or "get outta town".

Paul