Mary -
There are a number of Pros and Cons with each lead type. Basically, today's
J-Lead PLCC devices are physically larger and thicker than their gull-wing
Quad Flat Pack (QFP) equivalents. The J-Leads are more rugged and less
susceptible to damage than gull-wing leads, and thus can be more easily and
less expensively socketed. J-Leads are typically on a 50-mil pitch and it is
hard to visually inspect the solder joints for proper wetting, especially on
the inside (back) of the Lead. Gull-wing leaded equivalent packages have a
finer lead pitch, either 31.5, 25 or 20-mil pitch. For the inexperienced
user, the finer the pitch, the more difficulty they may have in assembly
because of their limited experience. Gull-wing leads are much easier to
inspect but, as alluded to earlier, they are more easily damaged, usually by
bending, if not handled properly.
Both types of components are generally available packaged in either waffle
trays or tape and reel. Very large QFP's are normally only available in
Waffle Trays.
I hope this limited response has helped to answer your question. If you need
any additional information, please feel free to contact me. Have a great
day!
Ed Valentine
Electronics Manufacturing Solutions
8612 Mourning Dove Road, Raleigh, NC 27615
Phone: (919) 270-5145, Fax: (919) 847-9971
Email: [log in to unmask]
Website: http://www.ems-consulting.com
----- Original Message -----
From: "Mary Knouse" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, June 21, 2001 5:22 PM
Subject: [DC] J-Legs or Gull Wings
> We are just starting to do surface mount, and I would like to know which
> PLCC's are better to use and have less problems for production, J-Legs or
> Gull Wings. Any information on this would be appreciated.
> Thanks,
> Mary
>
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