Electronic Components & Devices

Mounting

Design specifications of printed wiring board

Designs of land pattern

Since the amount of solder (fillet size) for mounting a capacitor on a printed circuit board influences the capacitor directly, sufficient consideration is necessary.
Confirm the suitable land pattern size in order to decide the suitable amount of solder.

When the amount of solder is too much, stress on a capacitor increases. It may cause a crack in the capacitor. When a land design of a printed wiring board is considered, it is necessary to set up the form and size of the land pattern so that the amount of solder is suitable.
When the amount of solder is too little, the adhesion (shear) strength of the terminal electrode may be insufficient, and the capacitor may drop off from the printed wiring board. The reliability of the circuit may also be affected.

Recommendation for land pattern size to which the amount of solder does not excessively increase.

[Recommended land pattern size of each case size]

 [Recommended land pattern size of each case size]

(Unit: mm)

SIZE Code a b c
JIS EIA
02 0402 01005 0.13 ~ 0.20 0.12 ~ 0.18 0.20 ~ 0.23
03 0603 0201 0.20 ~ 0.30 0.25 ~ 0.35 0.30 ~ 0.40
05 1005 0402 0.30 ~ 0.50 0.35 ~ 0.45 0.40 ~ 0.60
105 1608 0603 0.70 ~ 1.00 0.80 ~ 1.00 0.60 ~ 0.80
21 2012 0805 1.00 ~ 1.30 1.00 ~ 1.20 0.80 ~ 1.10
316 3216 1206 2.10 ~ 2.50 1.10 ~ 1.30 1.00 ~ 1.30
32 3225 1210 2.10 ~ 2.50 1.10 ~ 1.30 1.90 ~ 2.30
42 4520 1808 2.50 ~ 3.20(1) 1.80 ~ 2.30 1.50 ~ 1.80
43 4532 1812 2.50 ~ 3.20(1) 1.80 ~ 2.30 2.60 ~ 3.00
55 5750 2220 4.20 ~ 4.70 2.00 ~ 2.50 4.20 ~ 4.70

NOTE(1) The creepage distance of basic insulation may be required to be 2.5 mm or more. (See JIS C 6950-1) Therefore, the dimension of "a" for safety standard certified capacitors is recommended to be 3.0 mm to 3.5 mm.
When using a safety standard certified capacitor, consider a slit between lands or cleaning,
etc. to prevent electrical discharge from creepage.

When mounting two or more capacitors are mounted on the common land, it is necessary to separate the land with the solder resist strike so that it may become the exclusive land of each capacitor.
Unrecommended and recommended examples shown as following.

Recommended and unrecommended examples of soldering

Mounting
characteristic
Unrecommended Recommended
Mounting with
leaded component
Unrecommended Recommended
Mounting on the
vicinity of chassis.
Unrecommended Recommended
Wire soldering
after mounting
Unrecommended Recommended
Common solder
land with other
chip capacitors(2)
Unrecommended Recommended

NOTE(2) When a capacitor is mounted on a common solder land with another SMD, design the solder resist pattern so that the effective land pattern for the capacitor is exclusive and does not have excess solder.

Safety Application Guide for Multilayer Ceramic Chip Capacitors All Lists

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