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2. Land Dimensions
2-1. Chip capacitors can be cracked due to the stress
of PCB bending , etc. if the land area is larger than
needed and has an excess amount of solder.
Please refer to the land dimensions in table 1
for reflow soldering.
Please confirm the suitable land dimension by
evaluating of the actual SET / PCB.
Table 1 Reflow Soldering Method
Series
GJM
GJM
GJM
3. Board Design
When designing the board, keep in mind that the amount of strain which occurs will increase depending on the size
and material of the board.
JEMCGC-2703M
Chip Dimension
Chip(L×W)
(L/W) Code
02
0.4×0.2
03
0.6×0.3
15
1.0×0.5
Relationship with amount of strain to the board thickness, length, width, etc.]
3PL
ε=
Relationship between load and strain
2
2Ewh
L
When the load is constant, the following relationship can be established.
· As the distance between the supporting points (L) increases,the amount of strain also increases.
→Reduce the distance between the supporting points.
· As the elastic modulus (E) decreases, the amount of strain increases.
→Increase the elastic modulus.
· As the board width (w) decreases, the amount of strain increases.
→Increase the width of the board.
· As the board thickness (h) decreases, the amount of strain increases.
→Increase the thickness of the board.
Since the board thickness is squared, the effect on the amount of strain becomes even greater.
a
0.16 to 0.2
0.2 to 0.3
0.3 to 0.5
P
Y
h
w
22
Chip Capacitor
b
a
Solder Resist
b
0.12 to 0.18
0.2 to 0.35
0.35 to 0.45
ε：Strain on center of board (μst)
L：Distance between supporting points (mm)
w ：Board width (mm)
h ：Board thickness (mm)
2
E ：Elastic modulus of board (N/m
=Pa)
Y ：Deflection (mm)
P ：Load (N)
Notice
Land
c
0.2 to 0.23
0.2 to 0.4
0.4 to 0.6
(in mm)
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