Surface Mount Resistors
Safety Precautions (Common precautions for Surface Mount Resistors)
The following are precautions for individual products. Please also refer to the common precautions for Fixed
Resistors in this catalog.
1. Take measures against mechanical stress during and after mounting of Surface Mount Resistors
(hereafter called the resistors) so as not to damage their electrodes and protective coatings.
Be careful not to misplace the resistors on the land patterns. Otherwise, solder bridging may occur.
2. Keep the rated power and ambient temperature within the specified derating curve.
Some circuit boards, wiring patterns, temperatures of heat generated by adjacent components, or
ambient temper a tures can become factors in the rise of the temperature of the resistors, regardless of
the level of power applied. Therefore, check the conditions before use and op timize them so as not to
damage the boards and peripheral components.
Make sure to contact us before using the resistors under special conditions.
3. If a transient load (heavy load in a short time) like a pulse is expected to be applied, check and evaluate
the operations of the resistors when installed in your products before use. Never exceed the rated power.
Otherwise, the performance and/or reliability of the resistors may be impaired.
4. Transient voltage
If there is a possibility that the transient phenomenon (significantly high voltage applied in a short time)
may occur or that a high voltage pulse may be applied, make sure to evaluate and check the
characteristics of resistors mounted on your product rather than only depending on the calculated power
limit or steady-state conditions.
5. If the resistors are to be used in high frequency circuits, carefully check the operation before use.
Such circuits change the electrical characteristics of the resistors.
Before using halogen-based or other high-activity flux, check the possible effects of the flux residues on the
6.
performance and reliability of the resistors.
7. When soldering with a soldering iron, never touch the resistors'bodies with the tip of the soldering iron.
When using a soldering iron with a high temperature tip, finish soldering as quickly as possible
(within three seconds at 350 °C max.).
8. Mounting of the resistors with excessive or insufficient wetting amount of solder may affect the
connection reliability or the performance of the resistors. Carefully check the effects and apply a proper
amount of solder for use.
9. When the resistors' protective coatings are chipped, flawed, or removed, the characteristics of the
resistors may be impaired. Take special care not to apply mechanical shock during automatic mounting
or cause damage during handling of the boards with the resistors mounted.
10. Do not apply shock to the resistors or pinch them with a hard tool (e.g. pliers and tweezers). Otherwise,
the resistors' protective coatings and bodies may be chipped, affecting their performance.
11. Avoid excessive bending of printed circuit boards in order to protect the resistors from abnormal stress.
12. Do not immerse the resistors in solvent for a long time.
Before using solvent, carefully check the effects of immersion.
13. Do not apply excessive tension to the terminals.
01-Oct-19