The
Land
Grid Array,
or LGA,
is
a package that uses metal pads for
external electrical connection instead of leads (as in the
pin grid array) or solder balls (as in the
ball grid array). These metal pads, which
are called 'lands', are arranged in a grid or
array at the bottom of the package body, hence the name 'land grid array'.
The grid arrangement of the lands of the LGA package allows it to have a
high land count, making it a popular packaging option for devices with
high I/O requirements.
Typical LGA's have
land counts that range from 8 to 1681. LGA's with the lowest land counts
are basically QFN's, since the lands of these
packages just occupy the periphery of the body.
Land pitch
(distance between
lands) values typically used by the LGA range from 1.0 mm to 1.27
mm.
Table 1.
Properties of Some LGA's
|
No. of
Lands |
Body
Size |
Body
Thickness |
Land Pitch |
|
10 |
5 mm x 3
mm |
1.49 mm |
1.27 mm |
|
21 |
6.25 mm x
6.25
mm |
2.32 mm |
1.27 mm |
|
35 |
11.25 mm x
6.25
mm |
2.82 mm |
1.27 mm |
|
56 |
11.25 mm x
9
mm |
2.82 mm |
1.27 mm |
|
84 |
15 mm x 9
mm |
4.32 mm |
1.27 mm |
|
104 |
15 mm x 15
mm |
2.82 mm |
1.27 mm |
|
144 |
15 mm x 15
mm |
4.32 mm |
1.27 mm |
|
204 |
22 mm x 15
mm |
4.32 mm |
1.27 mm |
