Schottky diodes and TVS tubes should pay attention to these matters in use.

Schottky diodes and TVS tubes should pay attention to these matters in use.

Diodes occasionally have some minor faults in use. In fact, some minor problems can be prevented and can be effectively avoided. Next, we will introduce some things you should pay attention to when using Schottky diodes and TVS tubes.

Schottky diodes should be noted in the following applications:

1. The actual operating current of the application circuit should be less than the forward rated current If of the Schottky diode, generally not more than 60% of the rated If.

2. The peak operating voltage of the application circuit should be less than the highest reverse breakdown voltage Vrrm of the Schottky diode, typically no more than 80% of the rated voltage Vrrm.

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

4. For more demanding environments, in order to ensure reliability, Schottky diodes should be derated, especially considering the selection of forward rated current.

5. For applications with large surge voltages or surge currents, suppression and absorption circuits should be added.

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