1、 Schottky diode characteristics
1. The forward voltage drop of Schottky diode is much lower than that of fast recovery diode, so it has low power consumption and high efficiency. 2. Because the reverse charge recovery time is very short, it is suitable to work at high frequency.
3. It can withstand high surge current.
4. At present, the highest junction temperature of Schottky tubes commonly used in the market can be divided into 100 ℃, 125 ℃, 150 ℃ and 175 ℃ (the higher the junction temperature, the better the high temperature resistance of the product. That is, working below this temperature will not cause failure.
5. It also has some disadvantages: low withstand voltage and slightly large reverse leakage current. Comprehensive consideration shall be given to model selection. Schottky diodes are generally used in the secondary output rectifier of power supply.
2、 Packaging diagram of common Schottky models
Identify footprints by model:
Mbr10100: TO-220AC, single chip, two pins,
Mbr10100ct: TO-220AB, dual chip, three pin, model suffix with CT
Mbrb10100ct: to-263 (D2Pak), patch.
The fourth letter B in front of the model represents to-263, which is an international naming. Dual chip, three pin, model suffix with CT
Mbrd1045ct: TO-252 (DPAK), patch.
Mbrd and mbrb are patches, D: TO-252, B: to-263
Mbr3045pt: to-3p, model suffix "PT" stands for to-3p package,
The original Motorola (now on) was called sot-93
3、 Common models and parameters of Schottky diode
1. Schottky is a low-power, ultra-high-speed semiconductor device, which is widely used in switching power supply, frequency converter, driver and other circuits, as high-frequency, low-voltage, high current rectifier diode, freewheeling diode and protection diode, or as rectifier diode and small signal detection diode in microwave communication and other circuits.
2. Structure of Schottky diode Schottky diode is very different from PN junction diode in structural principle. Its interior is composed of anode metal (barrier layer made of molybdenum or aluminum), silicon dioxide (SiO2) electric field elimination material, n epitaxial layer (arsenic material), n-type silicon substrate, n cathode layer and cathode metal.
A Schottky barrier is formed between the n-type substrate and the anode metal.
When a positive bias voltage is applied at both ends of the Schottky barrier (the anode metal is connected to the positive pole of the power supply, and the n-type substrate is connected to the negative pole of the power supply), the Schottky barrier layer becomes narrower and its internal resistance becomes smaller; On the contrary, if a reverse bias is applied at both ends of the Schottky barrier, the Schottky barrier layer becomes wider and its internal resistance becomes larger.