Schottky diode, it is a low-power, ultra-high-speed semiconductor device. The most notable feature is the extremely short reverse recovery time. It is mostly used as high-frequency, low-voltage, high-current rectifier diode, freewheeling diode, protection diode, and also used as rectifier diode and small-signal detection diode in microwave communication and other circuits. It is more common in communication power supply and inverter. The biggest feature of Schottky diodes is that the forward voltage drop VF is relatively small. In the case of the same current, its forward voltage drop is much smaller. It is widely used in switching power supplies, frequency converters, drivers and other circuits, used as high frequency, low voltage, high current rectifier diodes, freewheeling diodes, protection diodes, or used as rectifier diodes, small signal detection diodes in microwave communication and other circuits.

1. Features of Schottky diodes:

    a. The forward voltage drop of Schottky diodes is much lower than that of fast recovery diodes, so its own power consumption is small and its efficiency is high.

    b. Since the reverse charge recovery time is extremely short, it is suitable to work in high frequency state.

    c. Can withstand high surge current.

    d. The reverse voltage resistance is high, and the market application prospect is very broad.

2. Schottky diode parameters

 a、Forward voltage VF

    VF is the voltage drop across the diode when the diode is conducting forward. The greater the current through the diode, the greater the VF; when the diode temperature is higher, the VF is smaller.

  b、Reverse current IR

    IR refers to the current flowing through the diode when a reverse voltage is added across the diode. The reverse current of the Schottky diode is larger. Choosing the Schottky diode is to choose the diode with the smaller IR as much as possible.

  c、Rated current IF

    Refers to the average current value converted according to the allowable temperature rise when the diode operates for a long time.

  d. Maximum inrush current IFSM

    Excessive forward current is allowed to flow. It is not a normal current, but an instantaneous current. This value is quite large.

  e. Maximum reverse peak voltage VRM

    Even if there is no reverse current, as long as the reverse voltage is continuously increased, sooner or later it will damage the diode. This reverse voltage that can be applied is not an instantaneous voltage, but a forward and reverse voltage that is repeatedly applied. Because the AC voltage is applied to the rectifier, its maximum value is an important factor specified. The maximum reverse peak voltage VRM refers to the maximum reverse voltage that can be applied to avoid breakdown. The highest VRM value of Schottky is currently 150V.

  f. Maximum DC reverse voltage VR

    The above-mentioned maximum reverse peak voltage is the peak voltage repeatedly applied, and VR is the value when the DC voltage is continuously applied. For DC circuits, the maximum DC reverse voltage is very important to determine the allowable value and upper limit.

  g. Maximum working frequency fM

    Because of the junction capacitance of the PN junction, when the operating frequency exceeds a certain value, its unidirectional conductivity will become worse. Schottky diodes have higher fM values, up to 100GHz.

  h. Reverse recovery time Trr

    When the operating voltage changes from a forward voltage to a reverse voltage, the ideal condition for diode operation is that the current can be cut off instantaneously. In fact, there is usually a delay. The amount that determines the current cutoff delay is the reverse recovery time. Although it directly affects the switching speed of the diode, it is not necessarily said that this value is small. That is, when the diode suddenly reverses from conduction, the reverse current decays greatly to the time required to approach IR. This indicator is very important when the high-power switch is working in the high-frequency switching state.

  i. Maximum power dissipation P

    When a current flows through the diode, it absorbs heat and raises its temperature. In practice, the external heat dissipation condition also has a great influence on P. Specifically, the voltage applied across the diode multiplied by the current flowing plus the reverse recovery loss