Thursday 24 May 2012

Schottky diode

Consider, a case where you want to isolate a battery supply with mains supply or incase you want to isolate two supplies, schottky diode is suitable for this application.

Schottky diode or surface barrier diode or hot carrier diode is a majority carrier, metal-semiconductor junction diode with very less reverse recovery time. The reverse recovery time is in picosec as compared to normal diodes that have reverse recovery in nanosec. Schottky conduts when forward biased. In many applications, we see schottky diode used in series with supply. Another advantage of schottky is less EMI noise. For normal diodes due to some reverse current flowing, in high-power applications EMI noise is a problem.

Advantages:
1. Less reverse recovery time and hence fast switching
2. Low EMI noise and hence preferred for high frequency applications
3. Smaller device area
4. Low forward drop (0.15 to 0.45V)
5. Low junction capacitance
6. High current density
7. Less power dissipation and hence small size heat sinks in high power applications

Disadvantages:
1. Low reverse voltage rating
2. Reverse current variation with temperature

Applications:
1. RF detector
2. Switching regulators
3. Diode mixer
4. Solar cell

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