Practical skills of selecting transient suppression diodes — SUNMATE
Practical skills of selecting transient suppression diodes
Transient voltage suppressor (TVS transient voltage suppressor for short) is a high-efficiency protection device in the form of diode. When the two poles of TVS diode are impacted by reverse transient high energy, it can change the high impedance between the two poles into low impedance at a speed of 10 negative 12th power second, absorb surge power up to several kilowatts, clamp the voltage between the two poles at a predetermined value, and effectively protect the precision components in the electronic circuit from various surge pulses. Many friends know little about transient suppression diodes, and even don't know how to choose them. Today I'll share with you the practical skills of choosing transient suppression diodes!
Selection skills of transient suppression diode:
1. Determine the maximum DC or continuous operating voltage of the protected circuit, the rated standard voltage of the circuit and the "high end" tolerance.
2. The rated reverse shutdown VWM of TVs shall be greater than or equal to the maximum working voltage of the protected circuit. If the selected VWM is too low, the device may enter an avalanche or the normal operation of the circuit may be affected by too large reverse leakage current. Serial connection is divided into voltage and parallel connection is divided into current.
3. The voltage of the TVS protection circuit should be smaller than the maximum voltage of the TVs.
4. Within the specified pulse duration, the maximum peak pulse power consumption PM of TVs must be greater than the possible peak pulse power in the protected circuit. After determining the maximum clamping voltage, the peak pulse current shall be greater than the transient surge current.
5. For the protection of data interface circuit, we must also pay attention to the selection of TVs devices with appropriate capacitance C.
6. The polarity and packaging structure of TVs are selected according to the purpose. It is reasonable to select bipolar TVs for AC circuit; TVS Array is more favorable for multi line protection.
7. Temperature considerations. The transient voltage suppressor can work between - 55 ~ + 150 ℃. If TVs is required to work at a changing temperature, because its reverse leakage current ID increases with the increase; The power consumption decreases with the increase of TVs junction temperature, which decreases linearly by about 50% from + 25 ℃ to + 175 ℃. The rain breakdown voltage VBR increases by a certain coefficient with the increase of temperature. Therefore, it is necessary to consult relevant product data and consider the influence of temperature change on its characteristics.