Soft Termination Multilayer
Ceramic Chip Capacitors
STSeries
MERITEK
RoHS
APPLICATION NOTES
STORAGE
To prevent the damage of solderability of terminations, the following storage conditions are
recommended:
Indoors under 5 ~ 40℃ and 20% ~ 70% RH.
No harmful gases containing sulfuric acid, ammonia, hydrogen sulfide or chlorine.
Packaging should not be opened until the capacitors are required for use. If opened, the pack should be
re-sealed as soon as is practicable. Taped product should be stored out of direct sunlight, which might
promote deterioration in tape or adhesion performance. The capacitors should be used within 6 months and
checked the solderability before use.
HANDLING
Chip capacitors are dense, hard, brittle, and abrasive materials. They are liable to suffer mechanical
damage, in the form of cracks or chips. Chip Capacitors should be handled with care to avoid contamination
or damage. To use vacuum or plastic tweezers to pick up or plastic tweezers is recommended for manual
placement. Tape and reeled packages are suitable for automatic pick and placement machine.
PREHEAT
In order to minimize the risk of thermal shock during soldering, a carefully controlled preheat is required.
The rate of preheat should not exceed 4℃ per second and the final preheat temperature should be within
100℃ of the soldering temperature for small chips such as 0603, 0805 and 1206, within 50℃ of the
soldering temperature for bigger chips such as 1210, 1808, 1812, 1825, 2220 and 2225, etc.
SOLDERING
Use middy activated rosin RA and RMA fluxes do not use activated flux. The amount of solder in each
solder joint should be controlled to prevent the damage of chip capacitors caused by the stress between
solder, chips, and substrate.
Hand soldering with temperature-controlled iron not exceeding 30 watts and diameter of tip less than 1.2
mm is recommended, tip of iron should not contact the ceramic body directly, and the temperature of iron
should be set to not more than 260℃.
For bigger chips such as 1210, 1808, 1812, 1825, 2220 and 2225, etc. wave soldering and hand
soldering are no recommended.
Recommended soldering profiles as following:
Soldering Solder Temp.(T) Soldering Time (t)
(℃)
soldering
235 – 260 ℃
230 – 260 ℃
Reflow
Wave
< 15 sec.
< 5 sec.
preheat
cooling
200
100
ΔT
ΔT
Chip Size
100 ℃
0603, 0805, 1206
50 ℃
1210, 1808, 1812, 1825, 2220, 2225
t
120 sec.
60 sec.
COOLING
After soldering, cool the chips and the substrate gradually to room temperature. Natural cooling in air is
recommended to minimize stress in the solder joint. A cooling rate not exceeding 4℃ per second should be
used when forced cooling is necessary.
CLEANING
All flux residues must be removed by using suitable electronic-grade vapor-cleaning solvents to
eliminate contamination that could cause electrolytic surface corrosion. Good results can be obtained by
using ultrasonic cleaning of the solvent. The choice of the proper system is depends upon many factors such
as component mix, flux, and solder paste and assembly method. The ability of the cleaning system to remove
flux residues and contamination from under the chips is very important.
Rev.7