1. Determine the maximum DC or continuous operating voltage of the protected circuit, the rated standard voltage of the circuit and the "high side" tolerance.
2. The rated reverse turn off VWM of TVs shall be greater than or equal to the maximum operating voltage of the protected circuit. If the selected VWM is too low, the device may enter avalanche or the normal operation of the circuit may be affected due to too large reverse leakage current. Connect the divided voltage in series and the divided current in parallel.
3. The maximum clamping voltage VC of TVs shall be less than the damage voltage of the protected circuit.
4. Within the specified pulse duration, the maximum peak pulse power consumption PM of TVs must be greater than the peak pulse power that may occur 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, attention must also be paid to selecting TVs devices with appropriate capacitance C.
6. The polarity and packaging structure of TVs are selected according to the application. It is reasonable to select bipolar TVs for AC circuit; It is more advantageous to select TVS Array for multi line protection.
7. Temperature considerations. The transient voltage suppressor can work between - 55 ~ + 150 ℃. If the TVS is required to work at a changing temperature, the reverse leakage current ID increases with the increase; The power consumption decreases with the increase of TVs junction temperature. From + 25 ℃ to + 175 ℃, it decreases linearly by about 50%. 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.
