John
Sorry for the misleading info..The parts are all SMT...The spacing between
the inner edges of the pads are 0.1"
_____________________________
Andre Leclair
Process Engineer
Ansen Corporation
315-393-3325 ext 293
315-393-7638 FAX
-----Original Message-----
From: John Burke [mailto:[log in to unmask]]
Sent: Wednesday, April 05, 2006 3:46 PM
To: Andre LeClair; TechNet E-Mail Forum
Subject: RE: [TN] Arching or Current Leakage
OK but from what you say this is a 0.1 pitch device which means it is
through hole?
If it is through hole what is the hole to copper clearance on the inner
layers around the holes for the leads to the nearest signal or plane in
mils?
John
John Burke
Senior Manager - Operations , Optichron
[log in to unmask]
W: 510 249 5233
M: 408 515 4992
http://www.optichron.com
Profile: https://www.linkedin.com/e/fps/2665502/
-----Original Message-----
From: Andre LeClair [mailto:[log in to unmask]]
Sent: Wednesday, April 05, 2006 12:42 PM
To: John Burke; TechNet E-Mail Forum
Subject: RE: [TN] Arching or Current Leakage
John
The customer has routed the lines on the outer layer. The closest
spacing
for pads and leads for this section of the circuit is 0.1.
_____________________________
Andre Leclair
Process Engineer
Ansen Corporation
315-393-3325 ext 293
315-393-7638 FAX
-----Original Message-----
From: John Burke [mailto:[log in to unmask]]
Sent: Wednesday, April 05, 2006 3:35 PM
To: TechNet E-Mail Forum; Andre LeClair
Subject: RE: [TN] Arching or Current Leakage
How are you routing that 500 volt line? Outer layer only (I hope) and
what is the spacing between conductors?
John
John Burke
Senior Manager - Operations , Optichron
[log in to unmask]
W: 510 249 5233
M: 408 515 4992
http://www.optichron.com
Profile: https://www.linkedin.com/e/fps/2665502/
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Andre LeClair
Sent: Wednesday, April 05, 2006 12:16 PM
To: [log in to unmask]
Subject: Re: [TN] Arching or Current Leakage
Jim
The circuit actually is from ERG incorporated into our customer's
design.
The failure is usually the transformer burning up (over heating) or if a
winding goes open the input transistors blow (smoke fire ect.). Our Test
Eng. is thinking there may be some small leakage across the cap (or
PCB).
The backlight is 6mA typical and the driver is also 6mA, so his thinking
that any increase in the load current and the transformer fails. Then
the
question was raised about n0-clean potentially contributing to this.
We have only seen a couple boards that had any sign of possible arching
at
the cap. The cap is an 18pf 4000v 5% COG from NovaCap.
I did manage to get a hold of a PCB layout recommendation for the
circuit
which suggests a slot between the cap pads and to conformal coat. (The
customer did not do this)
_____________________________
Andre Leclair
Process Engineer
Ansen Corporation
315-393-3325 ext 293
315-393-7638 FAX
-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Wednesday, April 05, 2006 2:28 PM
To: [log in to unmask]; [log in to unmask]
Cc: [log in to unmask]
Subject: Re: [TN] Arching or Current Leakage
Andre,
What is the failure mode of the circuitry - leaky capacitors on the
output
of the backlight driver? What type and voltage rating are the
capacitors?
Are there any external signs of the failure mode, ie burn marks,
electro-migration paths, etc?
Jim Carlson
Sr Quality Assurance/Reliability Engineer
Rockwell Collins EW-SIGINT
Phone 443-489-9121
Fax 443-489-9290
Andre Leclair <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
04/05/2006 02:11 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Andre Leclair <[log in to unmask]>
To
[log in to unmask]
cc
Subject
[TN] Arching or Current Leakage
We have a customer that has a portion of a circuit which randomly fails.
The circuit is a backlight driver (500volt 6mA). The output caps are
0.100
spacing of the terminals. The process used is No-clean. Can the
No-clean
contribute to failures of the circuit (ie promote arching or current
leakage across the body of the output caps). ???
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text
in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask]
or
847-615-7100 ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text
in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at:
http://listserv.ipc.org/archives
Please visit IPC web site
http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100
ext.2815
-----------------------------------------------------
---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
-----------------------------------------------------
|
