Design specifications of printed wiring board

Safety Application Guide for Multilayer Ceramic Chip Capacitors

Mounting

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]

(Unit: mm)

Size	Code		Dimension		Recommended land pattern dimensions
Size	JIS	EIA	L	W / T	a	b	c
02	0402	01005	0.4 ± 0.02	0.2 ± 0.02	0.13 ～ 0.20	0.12 ～ 0.18	0.20 ～ 0.23
03	0603	0201	0.6 ± 0.03	0.3 ± 0.03	0.20 ～ 0.25	0.25 ～ 0.35	0.30 ～ 0.40
			0.6 ± 0.05	0.3 ± 0.05	0.20 ～ 0.25	0.25 ～ 0.35	0.30 ～ 0.40
			0.6 ± 0.09	0.3 ± 0.09	0.23 ～ 0.30	0.25 ～ 0.35	0.30 ～ 0.45
05	1005	0402	1.0 ± 0.05	0.5 ± 0.05	0.30 ～ 0.50	0.35 ～ 0.45	0.40 ～ 0.60
			1.0 ± 0.15	0.5 ± 0.15	0.40 ～ 0.60	0.40 ～ 0.50	0.50 ～ 0.75
			1.0 ± 0.20	0.5 ± 0.20	0.40 ～ 0.60	0.40 ～ 0.50	0.50 ～ 0.75
105	1608	0603	1.6 ± 0.10	0.8 ± 0.10	0.70 ～ 1.00	0.80 ～ 1.00	0.60 ～ 0.90
			1.6 ± 0.15	0.8 ± 0.15	0.80 ～ 1.00	0.80 ～ 1.00	0.80 ～ 1.10
			1.6 ± 0.20	0.8 ± 0.20
			1.6 ± 0.25	0.8 ± 0.25
21	2012	0805	2.0 ± 0.10	1.25 ± 0.10	1.00 ～ 1.30	1.00 ～ 1.20	1.00～ 1.45
			2.0 ± 0.15	1.25 ± 0.15	1.00 ～ 1.30	1.00 ～ 1.20	1.25～ 1.55
			2.0 ± 0.20	1.25 ± 0.20	1.00 ～ 1.30	1.00 ～ 1.20	1.25～ 1.55
316	3216	1206	3.2 ± 0.20	1.6 ± 0.15	2.10 ～ 2.50	1.10 ～ 1.30	1.40 ～ 1.90
			3.2 ± 0.20	1.6 ± 0.20	2.10 ～ 2.50	1.10 ～ 1.30	1.60 ～ 2.00
			3.2 ± 0.30	1.6 ± 0.30	2.10 ～ 2.50	1.10 ～ 1.30	1.60 ～ 2.00
32	3225	1210	3.2 ± 0.30	2.5 ± 0.20	2.10 ～ 2.50	1.10 ～ 1.30	1.90 ～ 2.80

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
Mounting on the vicinity of chassis
Wire soldering after mounting
Common solder land with other chip capacitors(2)

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