-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Becerra Alejandro
Sent: Tuesday, December 03, 2002 9:10 AM
To: [log in to unmask]
Subject: Re: [TN] Tombstoning Film Chip Capacitor

Russell,

 

We're using the (B) version, reviewing this information in the web I found that the (X) version is recommended for reflow only and (B) for Wave and Reflow.

Do you know what is the difference in construction between (B) and (X) versions?

I would suggest change the version and footprint.

 

Regards

 

Alejandro Becerra

 

 

-----Original Message-----
From: Nowland, Russell Howard (Russell) [mailto:[log in to unmask]]
Sent: Tuesday, December 03, 2002 7:04 AM
To: 'TechNet E-Mail Forum.'; Becerra Alejandro
Subject: RE: [TN] Tombstoning Film Chip Capacitor

Alejando,

 

I had the same problem with the Panasonic ECHU family of thin film capacitors.  I had 142 on my board so you can imagine my frustration.  The problem is the polymer doesn't conduct heat therefore the part doesn't heat evenly.  The part body also does not stand up to heat very well.  During hand soldering you cannot apply much heat to the endcap or the body will melt.  Also, if you are repairing an adjacent component you must be very careful because the body will easily melt.  I don't like the parts but the circuit designers praise their functionality.  I worked with Panasonic and found that a standard discrete footprint did not work with the part.    I even ran a test vehicle that Panasonic provided to prove that the footprint is the biggest contributor to the phenomena.  They also came out with an improved endcap on the part but they gave it a new suffix.  The original version was the (C) and the new version has a (X) i.e. ECHU1H152JX5.  Using the (X) version improved the solderability marginally.  We then changed to their recommended footprint, which is in there datasheet, and the problem went away.  There footprint is not much bigger than the endcap on the part.  It is not what I would design but it works.  We did not play with the solderpaste composition by adding 2% silver so, I do not know how much that will help.  Here is the link to the Panasonic (X) version part.

 

http://www.panasonic.com/industrial/components/pdf/ef029_echu_x_dne.pdf

 

Good luck,

Russell Nowland
Lucent Technologies
Oklahoma City Works
Phone: (405) 782-7765
Fax: (405) 782-7905
email: [log in to unmask]

-----Original Message-----
From: Becerra Alejandro [mailto:[log in to unmask]]
Sent: Monday, December 02, 2002 7:24 PM
To: [log in to unmask]
Subject: [TN] Tombstoning Film Chip Capacitor

Hello to All,

We have had tombstoning in a Film Chip Capacitor (Size 1206).
It is being soldered in a normal reflow process, and this is the only component that it is showing tombstoning.
Reviewing the specs. of the component in the web I found that this capacitor is recommended for Wave Soldering.
Does anyone know the difference in construction between the Capacitors for Reflow and Wave Soldering?
Is it possible that this be cause for the tombstoning?
I am also sending pictures for cross section for the capacitors that we are using (Recommended for Wave Soldering).
They could be seen at Steve's site.

Regards

Alejandro Becerra

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