Surface Mount Components and ICs

[Barry A. Watzman]

IC sockets might be a solution in some cases.  But the following issues exist:

1. Some very fast circuits won't work with sockets [due to added capacitance]
2. It requires a chip made for the sockets.  Many of the QFP chips are not made in a "socketable" package.
3. It raises cost, sometimes dramatically [the socket can cost more than the chip, sometimes a LOT more].
4. Soldering the socket to the board may be as difficult as soldering the chip to the board

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From:  Harvey A. Kader [SMTP:optom at IBM.NET]
Sent:  Friday, April 23, 1999 8:46 PM
To:  HEATH at LISTSERV.TEMPE.GOV
Subject:  Surface Mount Components and ICs

Another possibility is to have all the ICs mounted into IC holders on
the board. This accomplishes two things -1) it allows for easy removal
of ICs without risking damage to the board or IC by
desoldering/resoldering, and 2) during kit building, if an error is
made, all one has to do is remove the IC holder, and not the chip
itself(less risk for damage).

Obviously, this way would raise the cost of the kit, but it is one way
to do it. In the early days of solid state in the early 60's, some
boards hade removable transistors. All the discrete components, in this
case transistors, were mounted in transistor holders. It was a relic of
the not too distance tube past where of course all tubes were mounted in
tube sockets for easy removal.

I remember some kits in the past having IC holders on the boards(I can't
remember whose kits they were).

Harvey A. Kader - http://www.angelfire.com/on/vacuumtubes

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