1N5822 Introduction
The 1N5822 is a Schottky diode, also known as a hot-carrier diode, which denotes that it has a very low forward voltage (0.525V drop) and an extremely fast switching time. The geometry is cutting-edge, with a chrome barrier metal, epitaxial construction with oxide passivation, and metal overlap contact. The 1N5822 is ideal for use as rectifiers in low-voltage, high-frequency inverters, as well as free-wheeling diodes and polarity protection diodes and performs better system efficiency compared to silicon p-n diodes.
1N5822 Schottky Pinout with Symbol
1N5822 Diode Specs & Features
Forward current: 3A
Speed: Fast Recovery: <=500ns, >200mA
Reverse Leakage Current: 2mA @ 40V
Low forward voltage drop
Very fast switching speed
Low power loss
Low stored charge
High forward surge capability
High frequency
Low forward resistance
1N5822 Diode Applications
RF mixer circuits
Power rectifier
Polarity protection devices
Clamping diodes
Free-wheeling
Detector diode
Power circuits
Overvoltage protection
DC/DC converters
1N5822 Schottky Diode Structure and Operation
The 1N5822 Schottky diode is made by combining semiconductor material with metal to form a barrier. There is no depletion region between them in this combination. This Schottky diode may be made of gold, silver, platinum, or tungsten, among other metals. In addition, gallium arsenide is the most commonly used semiconductor material other than silicon.
When no voltage is applied or the circuit is unbiased, electrons in the N-type material have a lower energy level than electrons in a metal. When the diode is forward biased, the electrons in the N-type gain energy and move with greater velocity. As a result, these electrons are referred to as Hot Carriers.
1N5822 Application Circuits
(step-down switching voltage regulator)
The above schematic is simple, easy to wire, and inexpensive, producing 5V from a 7V-40V unregulated supply with a maximum output current of 3A. The input voltage can be as high as 70V when using the LM2576HVT-5V version. Because of the inductor, the voltage at the switch node drops to several volts below ground during the reverse recovery time. The switch node’s steep negative voltage peaks cause interference, which can be capacitively coupled to other circuit segments. This interference can be reduced by inserting an additional Schottky diode.
(a step-down conversion with N-Channel MOSFETs and a Schottky diode)
Note: When using a Schottky diode with MOSFETs, to minimize parasitic inductance between the two, place the 1N5822 diode as close as possible to the MOSFET. Because parasitic inductance is harmful, MOSFETs with integrated Schottky diodes are available. Finally, while the conventional buck converter topology was used as an example in this article, these concepts apply to other switching converter types as well.
1N5822 Equivalents and Alternatives
BAT54C, SB340, 1N5820, 1N5821, SS34-3A
1N5822 Model Dimensions
Download 1N5822 Datasheet PDF
IN5822 Schottky Diode FAQ
1. Can I use MOSFET to replace 1N5822?
For fast switching circuits, use Schottky diodes for low voltage applications, and ultra-fast diodes for higher voltages. Because prices depend greatly on volumes, it might be cheaper to use the internal diode found in most power MOSFETS i.e. the IRF series of MOSFETS are quite cheap in India because of their widespread use. You can get one for less than half the price of a comparable diode.
2. What is a Schottky diode used for?
Schottky diodes are used at higher frequencies because of their low turn-on voltage, quick recovery time, and low energy loss. Schottky diodes are capable of rectifying a current due to their fast transition from conducting to blocking states.
3. What is the difference between 1N5822 and 1N5819?
They have very similar forward voltage and thermal resistance at the same conditions. However, the 1N5822 has higher leakage current level, which might cause problems to the power-OR of circuits containing a backup battery. Besides, for proper mounting and soldering work, the 1N5822 requires bigger holes.
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