Explanation of the difference between fast recovery diodes and Schottky diodes

Explanation of the difference between fast recovery diodes and Schottky diodes

There are many types of diodes, which have different effects on the circuit and the entire electrical appliance. So what is the difference between fast recovery diodes and Schottky diodes? Today, the editor will explain to you the difference between fast recovery diodes and Schottky diodes:

Fast recovery diodes refer to diodes with a very short reverse recovery time (less than 5us). Gold doping measures are often used in the process. Some of the structures use PN junction structures, and some use improved PIN structures. Its forward voltage drop is higher than ordinary diodes (1-2V), and its reverse withstand voltage is mostly below 1200V. In terms of performance, it can be divided into two grades:  fast recovery and ultra-fast recovery. The reverse recovery time of the former is hundreds of nanoseconds or longer, while that of the latter is below 100 nanoseconds.

Schottky diodes are diodes based on barriers formed by metal and semiconductor contacts, referred to as Schottky Barrier Diodes, which have a forward voltage drop (0.4--0.5V) and a short reverse recovery time ( 10-40 nanoseconds), and the reverse leakage current is large, the withstand voltage is low, generally lower than 150V, and it is mostly used in low voltage occasions.

These two tubes are usually used in switching power supplies.

The difference between Schottky diodesand  fast recovery diodes: the recovery time of the former is about a hundred times shorter than that of the latter, and the reverse recovery time of the former is about a few nanoseconds~!

The advantages of the former are low power consumption, high current, and ultra-high speed~! The electrical characteristics are of course diodes~!

The  fast recovery diode adopts gold-doped, simple diffusion and other processes in the manufacturing process, which can obtain high switching speed and high withstand voltage at the same time. At present, fast recovery diodes are mainly used as rectifying elements in inverter power supplies.

Schottky diode: low reverse withstand voltage value of 40V-50V, on-state voltage drop of 0.3-0.6V, and reverse recovery time of less than 10nS. It is a "metal-semiconductor junction" diode with Schottky characteristics. Its forward starting voltage is low. In addition to materials, the metal layer can also use gold, molybdenum, nickel, titanium and other materials. Its semiconductor material is silicon or gallium arsenide, mostly N-type semiconductors. This device is conducted by majority carriers, so its reverse saturation current is much larger than that of PN junctions conducted by minority carriers. Since the storage effect of minority carriers in the Schottky diode is very small, its frequency response is only limited by the RC time constant, so it is an ideal device for high frequency and fast switching. Its operating frequency can reach 100GHz. Also, MIS (Metal-Insulator-Semiconductor) Schottky diodes can be used to make solar cells or light-emitting diodes.

 fast recovery diode: It has a forward conduction voltage drop of 0.8-1.1V, a reverse recovery time of 35-85nS, and can quickly switch between on and off, which increases the frequency of use of the device and improves the waveform. The fast recovery diode adopts gold-doped, simple diffusion and other processes in the manufacturing process, which can obtain a higher switching speed and a higher withstand voltage at the same time. At present, fast recovery diodes are mainly used as rectifying elements in inverter power supplies.

Usually, fast recovery diodes of 5~20A are packaged in TO-220FP plastic package, high-power  fast recoverydiodes above 20A are packaged in TO-3P plastic package with metal heat sink on the top, fast recovery diodes below 5A are packaged in DO-41, DO -15, or D0-27 and other plastic packages.

Although fast recoverydiodes and Schottky diodes are both diodes, they bring different performances to electrical appliances. If you want to know more about fast recovery diodes, please call the editor.