Quickly understand the advantages and disadvantages of Schottky diodes

Quickly understand the advantages and disadvantages of Schottky diodes.

Schottky diodes are common in electronic applications, so what are the advantages and disadvantages of Schottky diodes?

Advantages of Schottky diodes:

Schottky diodes have the advantages of high switching frequency and low forward voltage, but their reverse breakdown voltage is relatively low, mostly no more than 60V, and the highest is only about 100V, which limits its application range. For example, the continuous current diodes of power switching devices in switching power supply (SMPS) and power factor correction (PFC) circuits, high frequency rectifier diodes over 100V for transformer secondary use, high speed diodes for 600V~1.2kV in RCD buffer circuits and 600V diodes for PFC boost, etc., only fast recovery epitaxial diodes (FRED) and ultra fast recovery diodes (UFRD) are used. The reverse recovery time of UFRD is also higher than 20ns, which can not meet the SMPS needs of 1MHz~3MHz in fields such as space station. Even if the hard switch is 100kHz SMPS, because the conduction loss and switching loss of UFRD are large, and the shell temperature is very high, a larger radiator is needed, so that the volume and weight of SMPS are increased, which does not accord with the development trend of miniaturization and thinning. Therefore, the development of high-voltage SBD above 100V has always been a research topic and the focus of attention. In recent years, SBD has made a breakthrough. 150V and 200V high voltage SBD have been put on the market, and SBD made of new materials that surpass 1kV has also been successfully developed, thus injecting new vigor and vitality into its application.

Disadvantages of Schottky diodes:

The biggest disadvantage of Schottky diodes is its low reverse bias voltage and large reverse leakage current, such as Schottky diodes made of silicon and metal, the rated voltage of Schottky diodes is only 50V, while the reverse leakage current is positive temperature characteristics. it is easy to increase rapidly with the increase of temperature, so the hidden worry of thermal runaway should be paid attention to in practical design. In order to avoid the above problems, the reverse bias of Schottky diodes is much smaller than its rating. However, the technology of Schottky diodes has also improved, and its reverse bias can be rated up to 200V.