Schottky diodes are divided into two types of packages: lead and surface mount (mount). Schottky diodes with leaded packages are usually used as high-frequency high-current rectifier diodes, freewheeling diodes or protection diodes. It offers single tube and dual tube (dual diode) packages. Schottky diodes have three pin extraction modes: common cathode (the cathodes of the two tubes are connected), common anode (the anodes of the two tubes are connected), and series (the anode of one diode is connected to the cathode of the other diode). Surface-mount Schottky diodes include single-tube, double-tube and triple-tube packages, with a to 19 pin lead methods.
The advantages of Schottky diodes are as follows:
1. Because the Schottky barrier height is lower than the PN junction barrier height, the forward conduction and forward voltage drop of the Schottky diode are lower than the PN junction diode (about 0.2V lower).
2. Because SBD is a majority carrier conduction device, there is no minority carrier lifetime and reverse recovery problems. The reverse recovery time of the SBD is only the charge and discharge time of the Schottky barrier capacitor, which is completely different from the reverse recovery time of the PN junction diode. Since the reverse recovery charge of the Schottky diode SBD is very small, the switching speed is very fast, and the switching loss is very small, which is especially suitable for high-frequency applications.
Disadvantages of Schottky diodes:
The disadvantages of Schottky diodes are low reverse bias voltage and large reverse leakage current. For example, a Schottky diode made of silicon and metal has a reverse bias voltage rated withstand voltage of only 50V, while the value of the reverse leakage current is a positive temperature characteristic, which tends to increase rapidly as the temperature rises. . In actual design, attention should be paid to the hidden dangers of thermal runaway. In order to avoid the above-mentioned problems, the reverse bias voltage of the Schottky diode in actual use is much smaller than its rated value. Of course, with the advancement of technology and Schottky diode technology, its reverse bias voltage rating will also increase.
Application of Schottky diode in switching power supply:
The switching power supply is composed of main components such as high frequency transformer, high frequency capacitor, high reverse voltage and high power transistor, power rectifier diode, and control integrated circuit. As a kind of energy-consuming component, the secondary rectifier diode has a large loss (about 30% of the power consumption) and a large amount of heat. The choice is very important to the overall efficiency and reliability of the power supply. Schottky diodes are required to have the characteristics of small forward voltage drop VF, small reverse leakage IR, and short recovery time Trr under high-speed and high-current working conditions.
What I have explained above is the advantages and disadvantages of Schottky diodes and the package style. I hope that after reading it, it will be helpful to you. If you want to know more about Schottky diodes, please contact customer service online or Call the company's service hotline (upper right corner of the website) for consultation, we will be happy to provide you with quality service!