These matters should be paid attention to in the use of Schottky diodes and TVS tubes.

These matters should be paid attention to in the use of Schottky diodes and TVS tubes.

There will be some minor failures occasionally in the use of diodes, in fact, some minor problems can be prevented and can be effectively avoided. Next, we will introduce some matters that should be paid attention to in the use of Schottky diodes and TVS diodes.

Schottky diodes should pay attention to the following points in application:

1. The actual working current of the application circuit should be less than the forward rated current If of the Schottky diode, generally no more than 60% of the rated If.

two。. The peak operating voltage of the application circuit should be less than the maximum reverse breakdown voltage Vrrm of the Schottky diode, generally no more than 80% of the rated voltage Vrrm.

3. The actual temperature rise of Schottky diodes in the application circuit should be less than the maximum junction temperature Tjmax of Schottky diodes.

4. For the more demanding environment, in order to ensure reliability, Schottky diodes should be reduced, especially considering the selection of forward current rating.

5. Suppression and absorption circuits should be added to the application circuits with large surge voltage or surge current.

6. The replacement of Schottky diodes should try to choose the original model, because different types of Schottky forward voltage drop Vf and reverse breakdown voltage Vr, reverse leakage current Ir are different. For example, SR5100 is used to replace SR540. Although the reverse breakdown voltage of SR5100 is higher than that of SR540, it seems to be no problem. However, the forward voltage drop of SR5100 is higher than that of SR540. If it is used in the power supply circuit of set-top box, the + 5V and + 12V voltages will deviate from the normal value too much, and the power consumption will increase.