When mentioning low-power, high-current, and ultra-high-speed semiconductor devices, many engineers will surely first think of the Schottky Barrier Diode (SBD). But do you really know how to use them? Compared to other diodes, what makes the Schottky diode so special? Let's highlight the key points below.

Key Parameters of Schottky Diodes

Schottky diodes are widely used in circuits such as switching power supplies, frequency converters, and drivers. Different factors need to be considered in various applications, and the performance of different devices varies. Therefore, when selecting a Schottky diode, the following key parameters must be considered comprehensively. 1. Forward Voltage Drop (): is the voltage drop across the diode when it is conducting in the forward direction. The larger the current passing through the diode, the larger the ; as the diode temperature increases, the decreases. 2. Reverse Saturation Leakage Current (): refers to the current flowing through the diode when a reverse voltage is applied across it. Schottky diodes have a relatively large reverse leakage current; when selecting one, try to choose a diode with a smaller .
3. Rated Current (): Refers to the average current value calculated based on the allowable temperature rise during long-term operation of the diode.

4. Maximum Surge Current (): The excess forward current allowed to flow. It is not a normal current but an instantaneous current, and this value is quite large.

5. Maximum Peak Reverse Voltage (): Even if there is no reverse current, as long as the reverse voltage is continuously increased, the diode will eventually be damaged. This applicable reverse voltage is not an instantaneous voltage, but the repeatedly applied forward and reverse voltages. Since AC voltage is applied to the rectifier, its maximum value is a critical specified factor. Maximum Peak Reverse Voltage () refers to the maximum reverse voltage that can be applied to avoid breakdown. Currently, the highest value for Schottky diodes is 150V.

6. Maximum DC Reverse Voltage (): While the aforementioned maximum peak reverse voltage is for repeatedly applied peak voltages, is the value for continuously applied DC voltage. For DC circuits, the maximum DC reverse voltage is very important for determining the allowable and upper limit values. 7. Maximum Operating Frequency (): Due to the junction capacitance of the PN junction, when the operating frequency exceeds a certain value, its unidirectional conductivity will deteriorate. Schottky diodes have a higher value, which can reach up to 100GHz. 8. Reverse Recovery Time (): When the operating voltage changes from forward to reverse, the ideal situation is for the current to be cut off instantaneously. In reality, there is usually a slight delay. The quantity determining this delay is the reverse recovery time. Although it directly affects the switching speed of the diode, it does not necessarily mean that a smaller value is always better. Specifically, it is the time required for the reverse current to decay from a large value to close to when the diode suddenly reverses from conduction. This metric is vital when high-power switching transistors operate in high-frequency switching states.
9. Maximum Power Dissipation (): When current flows through the diode, it absorbs heat, causing its own temperature to rise. In practice, external heat dissipation conditions have a significant impact on . Specifically, it is the voltage across the diode multiplied by the flowing current plus the reverse recovery loss.