Many parameters of SMD capacitors are closely related to temperature. When using, pay attention to whether the temperature affects the capacitor, etc.

The effect of temperature on the life of capacitors usually shortens as the temperature increases, so the effect of temperature on the life of capacitors is very large. When using chip capacitors, the effect of temperature on capacitors should be fully considered, and the capacitors should be operated at around 20°C as much as possible to avoid the effect of temperature on capacitor parameters.

Whether it is a high-temperature ceramic capacitor, a high-temperature aluminum electrolytic capacitor or a high-temperature tantalum electrolytic capacitor, its capacity, accuracy and withstand voltage are inversely proportional, that is, the larger the capacity, the smaller the withstand voltage and the worse the accuracy. At the same time, the larger the capacity, the larger the volume of the capacitor. The price of high-temperature capacitors is closely related to their temperature range and capacity.

1. Poor heat dissipation

2. Placing the product in the heat radiation area of the heat source.

3. Self-heating and overload use; The following are the explanations.
(1) When AC is loaded, the capacitor itself will generate heat due to the existence of equivalent series resistance;
(2) Because the rapid charging and discharging causes the equivalent series resistance of the capacitor to heat up, special attention should be paid to leaving enough margin in high-frequency circuits;
(3) Using the capacitor when applying over voltage beyond the rated operating range;
Note: Keep the surface temperature below the upper limit operating temperature to make the surface temperature of the capacitor (including part of the heat generated by itself).

4. The heat generated by the capacitor itself causes the following three problems, and the explanations are as follows.
(1) When AC is applied, the capacitor itself generates heat due to the equivalent series resistance, especially in high-frequency circuit applications.
(2) Sudden charging and discharging causes heat to be generated at the equivalent series resistance of the capacitor;
(3) When using the capacitor, such as over voltage, it exceeds the rated operating range;
If used for coils that generate heat, please confirm whether the increase in the surface temperature of the capacitor is less than 20°C and keep its surface temperature below the upper limit of the operating temperature.
Note: The surface temperature of the capacitor, including part of the heat generated by itself, must be lower than the upper limit of the operating temperature.

5. Effect of temperature on capacitor performance;
(1) At high temperatures: 
The electrostatic capacitance decreases. The equivalent series resistance increases, and the loss increases. 
The insulation resistance decreases, and the product life is reduced.
(2) At low temperatures: 
The electrostatic capacitance decreases. The equivalent series resistance increases.
If the operating temperature range of Class II MLCC chip capacitors is wide, the electrostatic capacitance may change greatly. 

To ensure the electrostatic capacitance, the following methods are recommended:
(1) Control the operating temperature range to reduce the change in electrostatic capacitance caused by temperature;
(2) Select capacitors made of suitable materials;

Note: The DC voltage characteristics and the placement characteristics of the electrostatic capacitance must be considered before selecting the capacitor.