500R07S0R2AV4T Datasheet, PDF (3/3 Pages) Johanson Technology Inc. – APPLICATION NOTES FOR CERAMIC CHIP CAPACITORS

APPLICATION NOTES FOR CERAMIC CHIP CAPACITORS
BOARD LAYOUT & PAD DESIGN
Solder pad design, solder application, and component placement are important elements of the soldering process.
Excessive transfer of thermal or mechanical stresses to the MLC can result from oversized solder fillets. Nominal
pad designs for solder reflow process are listed in Table 1. These guidelines represent a starting point in Printed
Circuit Board (PCB) design.
Further information is the Institute for Interconnecting and Packaging Electronic Circuits (www.ipc.org) has developed
and published IPC-SM-782A “Surface Mount Design and Land Pattern Standard”.
(L)
(S)
(W)
CHIP SIZE
LENGTH
SEPARATION
WIDTH
min
max
min
max
min max
0201
IN
0.008 0.014 0.008 0.012 0.008 0.016
0603 mm
0.20 0.35
0.20
0.30
0.20 0.40
0402
IN
0.014 0.018 0.012 0.020 0.016 0.024
W
1005 mm
0.35 0.45
0.30
0.50
0.40 0.60
0603
IN
0.024 0.028 0.024 0.031 0.024 0.031
1608 mm
0.60 0.70
0.60
0.80
0.60 0.80
L
S
L
0805
IN
0.024 0.028 0.039 0.047 0.031 0.043
2012 mm
0.60 0.70
1.00
1.20
0.80 1.10
1210
IN
0.039 0.047 0.079 0.094 0.071 0.091
3225 mm
1.00 1.20
2.00
2.40
1.80 2.30
Table 1 Reflow Pad Dimensions
SOLDER FILLETS
To avoid detrimental effects of thermal and mechanical
stress it is essential that the solder fillet be limited to
2/3rds of the overall height of the MLC termination as
illustrated in the figure below. The solder fillet can be
controlled by solder paste deposition and pad design in
reflow and vapor phase processes and by pad design
and use of hot air knives in the wave process.
TOMB STONING / CHIP MOVEMENT
Tomb-stoning or draw bridging is illustrated in the
figure below. Tomb-stoning or other undesirable chip
movements may result if unequal surface tension forces
exist as the molten solder wets the MLC terminations
and mounting pads. This tendency can be minimized
by insuring that all factors at both solder joints are
equal, namely; pad size, solder mass, termination size,
component position and heating. Tomb-stoning is
easily avoided through proper design, material selection
and proofing of the process.
Solder Fillet
End Terminations
Ceramic Body
Mounting Pads
Printed Circuit Board (PCB)
Solder Fillet
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