Application and Selection of Tantalum Capacitors in Power Supply Circuits
Time:2023-08-02
Views:789
1. The superior characteristics of tantalum capacitors may keep you in love
Tantalum capacitors have a wide operating temperature range, stable temperature characteristics, large specific capacity, and unique self-healing characteristics, which can meet the stability of long-term operation.
2. The inherent fatal weakness of tantalum capacitors makes you hate iron for not becoming steel
The key component of ordinary tantalum capacitors is Ta2O5, which causes unstable stress when heated. The reliable voltage for use is low, and the ability to withstand surge voltage and current is poor. The failure mode is short circuit, which can easily cause high temperature, fire, and other injuries.
Figure 1 Schematic diagram of tantalum capacitor failure
3. The Key to Reliable Application of Tantalum Capacitors
(1) As shown in Figure 1, the working voltage of the tantalum Manganese dioxide capacitor described above will decrease with the increase of temperature. When the temperature is higher than 85 ℃, the recommended voltage is 33% of the rated voltage, and the failure risk can be greatly reduced.
Figure 2 Temperature and Voltage Derating Curve of Tantalum Capacitor
(2) Control the temperature of tantalum capacitors, reduce ripple current, and stay away from heat sources.
(3) Try not to place tantalum capacitors on the input side of the power supply for filtering. When the power is turned on, large impulse currents can easily cause tantalum capacitors to fail.
(4) Change to tantalum polymer capacitor: the tantalum Manganese dioxide capacitor introduced above has many fatal weaknesses, so it is forbidden in some occasions. While tantalum polymer capacitors retain many advantages of tantalum Manganese dioxide capacitors, their failure risks are greatly reduced. Figure 3 shows the recommended use voltage of tantalum polymer capacitor, which is significantly improved in voltage tolerance compared with tantalum Manganese dioxide capacitor.
Figure 3 Appearance of tantalum Manganese dioxide and tantalum polymer capacitor
Figure 4 Temperature Voltage Derating Characteristics of Typical Tantalum Polymer Capacitors
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