Searching \ for '[EE] Moisture Sensitive Chips was Re: [EE]TSSOP f' in subject line. ()
Make payments with PayPal - it's fast, free and secure! Help us get a faster server
FAQ page: www.piclist.com/techref/index.htm?key=tssop+EE%5D
Search entire site for: 'Moisture Sensitive Chips was Re: [EE]TSSOP f'.

Exact match. Not showing close matches.
PICList Thread
'[EE] Moisture Sensitive Chips was Re: [EE]TSSOP f'
2004\10\17@120604 by Bob Axtell

face picon face
In earlier days, the plastic covering of the chip was quite thick, and
would provide
protection from fairly high external pressure. In other words, water
pressure would have to be
very high to get through to the device inside.

But these very thin packages do not have the level of protection that
thick packages have.
If you clean with water, you should bake the PCB to ensure the removal
of any trapped water.
I consider TSSOP to fall into this catagory.

What I do is to clean with paint thinner first, then use hot soapy
water, then clean water, then
a small 125F bakeout in the oven (make sure temp is reached then turn
the oven off and let everything
slowly dry out and cool down at the same time). bakeout lasts for about
1 hr.

If I believe moisture is going to be a problem, I will dipcoat the final
PCB with an RTV coating.

F

Philip Stortz wrote:

{Quote hidden}

--
Note: Attachments must be sent to
spam_OUTattachTakeThisOuTspamengineer.cotse.net, and
MAY delay replies to this message.
       520-219-2363

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@134511 by Anthony Toft

flavicon
face
> If I believe moisture is going to be a problem, I will dipcoat the final
> PCB with an RTV coating.

Is there any source for RTV readily available to the hobbiest, other
than the tubes of locktite available in Autoparts stores? I have a
circuit that will need to be coated for short protection.

Anthony
--
Anthony Toft <.....toftatKILLspamspam@spam@cowshed.8m.com>
    I'm Anton, and I approve this message

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@140725 by Bob Axtell

face picon face
There more to this than first meets the eye. Lets say you design
something that goes into aviation
equipment, flying at 50000'. Small amounts of pressure trapped inside
the thin case might crack the
case. High vibration levels might also crack a thin case. The device
might work fine until the plane
sits on the ground for a few days in a humid place (like central
America) and moisture becomes
trapped in the cracked case.

The solution is to coat the devices with a semi-hard RTV coating. The
flexibility of the coating ensures
that moisture can't get it whether the case cracks or not. Hard coatings
will eventually crack due to
vibration.

--Bob

Bob Axtell wrote:

{Quote hidden}

--
Note: Attachments must be sent to
attachspamKILLspamengineer.cotse.net, and
MAY delay replies to this message.
       520-219-2363

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@140958 by Bob Axtell

face picon face
Check the internet for "electronic encapsulants". They are usually two-part
compounds. GE makes electronic coatings, as do DuPont and many others.

--Bob

Anthony Toft wrote:

{Quote hidden}

--
Note: Attachments must be sent to
.....attachKILLspamspam.....engineer.cotse.net, and
MAY delay replies to this message.
       520-219-2363

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@141800 by Marc Nicholas

flavicon
face
Or "conforming coatings". I recall there's one that comes in a spray can.

Nasty stuff, however.


-marc

On Sun, 17 Oct 2004, Bob Axtell wrote:

{Quote hidden}

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@142101 by Bob Axtell

face picon face
There IS one wonderful compound made by Rustoleum, used to make rubberized
handles for pliers, etc. The stuff is expensive but works very well - I used
it for 220VAC circuits on a PCB with low level circuits-

"GRIP & GUARD  Texturized Rubber Coating", comes in a 14.5 fl oz dip
can, in many
colors (I like baby blue best), sold in all ACE hardware stores. It has
a very high dielectric
strength, and is NOT rubber (its a new plastic resin in xylene/acetone
cure). It never hardens,
chips, or cracks.

--Bob

Anthony Toft wrote:

{Quote hidden}

--
Note: Attachments must be sent to
attachspamspam_OUTengineer.cotse.net, and
MAY delay replies to this message.
       520-219-2363

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@151240 by Roland

flavicon
face
At 02:12 PM 17/10/2004 -0400, you wrote:
>Or "conforming coatings". I recall there's one that comes in a spray can.
>
>Nasty stuff, however.
>

Does anyone use 'clear laquer'(in a can) as a conformal coating. Basically
clear automotive paint.
I have, but it's not the best if you need to do repairs afterwards, but is
tolerable.
Very cheap, and seems to work well enough on cars as an anti-moisture:)


Regards
Roland Jollivet

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@152000 by Marc Nicholas

flavicon
face
Clear lacquer isn't a conforming coating....it's not flexible, it won't
build up in a thick enough layer to get into everything, and it'll likely
crack over time, IMHO.


-marc

On Sun, 17 Oct 2004, Roland wrote:

{Quote hidden}

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@153746 by Bob Axtell

face picon face
I used to use it, but found out that it cracks and chips.
Lets moisture in eventually.

Unless they have changed the formula...

--Bob

Roland wrote:

{Quote hidden}

--
Note: Attachments must be sent to
@spam@attachKILLspamspamengineer.cotse.net, and
MAY delay replies to this message.
       520-219-2363

_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@191009 by hilip Stortz

picon face
sure, allied, newark, and most other distributors carry non-corrosive
rtv (you want to make sure it's non-corrosive, most rtv is corrosive and
will damage circuitry).  mcm.com may also have it, i haven't checked.
there are also spray conformal coatings that are silicone or other
materials.  miller-stephenson is my preferred source for aerosol
chemicals.  they are good about sample's (for a reduced price) though
they do have a substantial minimum order requirement.

Anthony Toft wrote:
>
> > If I believe moisture is going to be a problem, I will dipcoat the final
> > PCB with an RTV coating.
>
> Is there any source for RTV readily available to the hobbiest, other
> than the tubes of locktite available in Autoparts stores? I have a
> circuit that will need to be coated for short protection.
------

--
President George W. Bush, Vice President Richard B. Cheney, Secretary of
Defense Donald H. Rumsfeld,
and Attorney General John D. Ashcroft have committed violations and
subversions of the Constitution
of the United States of America.  <http://www.VoteToImpeach.org>  They should
be charged with high treason
and as leaders deserve the highest penalty.  If there is no rule of law
there can be no civilization.
_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\17@191553 by hilip Stortz

picon face
i'm glad i asked!  most of what i've seen is more concerned with damage
done during soldering when trapped moisture gets rapidly heated and
expands, creating a crack (or damaging a bond wire even i'd think).
it's good to know it's an ongoing problem and necessitates a conformal
coating.  i know i've seen chips in packages that are thinner than the
naked chips once were!  it's my understanding that some of them have the
back surface ground down after the rest of the manufacturing but before
packaging.  amazing infrastructure there, all industries could learn a
lot from how chips are made (in terms of reliability and quality, as
well as management of a very complex manufacturing process).  then
again, according to dentist i've had people who work in those clean
rooms have a very high incidence of TMJ, not surprising, i can see a lot
of stress in one of those jobs (and it can't help that you can't see all
of other people's faces, making it hard to understand their facial
expression and whether they are joking or deadly serious).

Bob Axtell wrote:
>
> There more to this than first meets the eye. Lets say you design
> something that goes into aviation
> equipment, flying at 50000'. Small amounts of pressure trapped inside
> the thin case might crack the
> case. High vibration levels might also crack a thin case. The device
> might work fine until the plane
> sits on the ground for a few days in a humid place (like central
> America) and moisture becomes
> trapped in the cracked case.
------

--
President George W. Bush, Vice President Richard B. Cheney, Secretary of
Defense Donald H. Rumsfeld,
and Attorney General John D. Ashcroft have committed violations and
subversions of the Constitution
of the United States of America.  <http://www.VoteToImpeach.org>  They should
be charged with high treason
and as leaders deserve the highest penalty.  If there is no rule of law
there can be no civilization.
_______________________________________________
http://www.piclist.com
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist

2004\10\19@055145 by jsand

flavicon
face
Hello Roland & PIC.ers,

>Does anyone use 'clear laquer'(in a can) as a conformal coating. Basically
>clear automotive paint.
>I have, but it's not the best if you need to do repairs afterwards, but is
>tolerable.
>Very cheap, and seems to work well enough on cars as an anti-moisture:)
>
>
>Regards
>Roland Jollivet

I've been using CRC clear Urethane Seal Coat
'Motor & Generator Winding Coating Insulator'  
Manufacturer's code 2049.

Available from Waco Industries, Johannesburg
tel   011 677 2500
costs about R30 a can in case qtys.

It's acetone soluble, for when you need to do board repairs.
Sprays on THICK, doesn't crack off or cause other unwanted
effects - as the household stuff will do to you.
Superb insulator. Some headers on a pcb here were recently coated
with it (in error) and the pins became completely impervious to 240vac.


           best regards,   John



email from the desk of John Sanderson.
JS Controls, PO Box 1887, Boksburg 1460, Rep. of S. Africa.
Tel/Fax 011 893 4154,
Cell 082 741 6275,
web    http://www.jscontrols.co.za
Manufacturer & purveyor of laboratory force testing apparatus &
related products & services.
email from the desk of John Sanderson.
JS Controls, PO Box 1887, Boksburg 1460, Rep. of S. Africa.
Tel/Fax 011 893 4154,
Cell 082 741 6275,
web    http://www.jscontrols.co.za
Manufacturer & purveyor of laboratory force testing apparatus &
related products & services.

____________________________________________

More... (looser matching)
- Last day of these posts
- In 2004 , 2005 only
- Today
- New search...