Several parameters must be considered when selecting Schottky diode — SUNMATE
Several parameters must be considered when selecting Schottky diode
We often use Schottky diodes in switching power supplies, but the performance varies greatly due to different manufacturers and other reasons. When selecting Schottky diodes, we must consider the following parameters:
1. Conduction voltage drop VF
VF is the voltage drop at both ends of the diode when the schottky diode is in the forward direction. The greater the current through the diode, the greater the VF; The higher the diode temperature, the smaller the VF.
Several parameters must be considered when selecting Schottky diode
2. Reverse saturated leakage current IR
IR refers to the current flowing through the Schottky diode when the reverse voltage is applied at both ends of the Schottky diode. The Schottky diode has a large reverse leakage current. The Schottky diode with a smaller IR is selected as far as possible.
3. Rated current IF
It refers to the average current value converted according to the allowable temperature rise during long-term operation of Schottky diode.
4. Greater surge current IFSM
Excessive forward current allowed to flow. It is not a normal current, but an instantaneous current, which is quite large.
Several parameters must be considered when selecting Schottky diode
5. Larger reverse peak voltage VRM
Even if there is no reverse current, as long as the reverse voltage is continuously increased, the Schottky diode will be damaged sooner or later. The reverse voltage that can be applied is not an instantaneous voltage, but a repeatedly applied forward and reverse voltage. Since AC voltage is applied to the rectifier, its greater value is the specified important factor. The larger reverse peak voltage VRM refers to the larger reverse voltage that can be applied to avoid breakdown. Currently, Schottky's higher VRM value is 150V.
6. Larger DC reverse voltage VR
The larger reverse peak voltage mentioned above is the peak voltage repeatedly applied, while VR is the value obtained by continuously applying DC voltage. For DC circuits, a larger DC reverse voltage is crucial for determining the allowable and upper limits.