Schottky diode is a semiconductor device, which has three characteristics: low power consumption, high current and ultra-high speed. It is made by using the principle of metal-semiconductor junction formed by the contact between metals and semiconductors. Medium and small power Schottky diodes are generally packaged.
The advantages of Schottky diode are as follows:
1. Because the height of Schottky barrier is lower than that of PN junction barrier, the forward conduction and forward voltage drop of Schottky diode are lower than that of PN junction diode (about 0.2V lower).
2. Because SBD is a majority carrier conducting device, there are no minority carrier lifetime and reverse recovery problems. The reverse recovery time of SBD is only the charge-discharge time of Schottky barrier capacitor, which is completely different from that of PN junction diode. Because the reverse recovery charge of 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.
Shortcomings of Schottky diode:
The disadvantages of Schottky diode are low reverse bias voltage and large reverse leakage current. For example, the rated withstand voltage of the reverse bias voltage of Schottky diode made of silicon and metal is only up to 50V, while the value of the reverse leakage current is a positive temperature characteristic, which is easy to increase rapidly with the rise of temperature. In actual design, attention should be paid to the hidden danger of thermal runaway. In order to avoid the above problems, the reverse bias voltage of Schottky diode in practical use is far less than its rated value. Of course, with the progress of technology and Schottky diode technology, its reverse bias voltage rating will also increase.
Packaging form of Schottky diode:
Schottky diodes can be packaged in two forms: lead and surface mounting. Schottky diodes with lead packaging are usually used as high-frequency high-current rectifier diodes, free-wheeling diodes or protective diodes. Schottky pairs have three ways to lead out pins: common cathode (the negative pole of the two tubes is connected), common anode (the positive pole of the two tubes is connected) and series (the positive pole of one diode is connected to the negative pole of the other diode). It has two packaging forms: single-tube type and double-tube (double-diode) type. The Schottky diodes with surface packaging have various packaging forms, such as single-tube type, double-tube type and three-tube type, and there are A~19 pin extraction methods.