Don Hyde wrote:
.........
>If you're not familiar with them, a 44-pin QFP is a flatpack a little under
>1/2" square (10mm, actually), with 11 teensy little leads on each side.
>They're not intended to go into a socket, but are soldered directly to rows
>of little pads on the surface of the board.
>
>The PLCC package is somewhat larger, and is almost always put in a socket.
>By the time you have it in the socket, it doesn't save all that much board
>space over a 40-pin DIP -- it probably occupies 1/2 to 3/4 as much board
>space.
>

Here are some measurements:

44-pin PLCC chip - 17mm x 17 mm
44-pin PLCC socket - 23.5mm x 23.5 mm
40-pin DIP chip - 18mm x 52mm

So, PLCC in socket saves about 40% on area. However, it sure
looks a bunch smaller.

Main advantage of PLCC over QFP is any mortal can work with one.

QFP type is "usually" soldered by machine - although there have
been several past threads where dozens of people with tiny itty-bitty
little fingers have come forth saying those miniscule leads are no
problem to work with.

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