1N5822 Schottky Diode: Pinout, Datasheet, and Applications

Quick answer

The 1N5822 is an axial Schottky barrier rectifier commonly specified for 3 A average forward current and 40 V repetitive peak reverse voltage in a DO-201AD package. Its banded end is the cathode. Typical uses include low-voltage converter outputs, freewheeling paths, and reverse-polarity protection.

Those headline values are not unconditional. The 3 A rating depends on the manufacturer's thermal test setup, and the 40 V value is a maximum repetitive reverse-voltage rating rather than a recommended operating target. The base number also does not make every manufacturer's version interchangeable. Design and source against the exact manufacturer, ordering suffix, datasheet revision, and circuit conditions.

What is a 1N5822?

The 1N5822 belongs to the 1N5820/1N5821/1N5822 axial Schottky family. In Vishay's family datasheet, the three devices share a 3 A current class and DO-201AD package, while their repetitive peak reverse-voltage ratings increase from 20 V to 30 V and 40 V. The 1N5822 is the 40 V member of that specific family.

Schottky rectifiers are useful in low-voltage power paths because their relatively low forward drop can reduce conduction loss and their reverse recovery is fast. The tradeoff is that reverse leakage rises with temperature. A real design must therefore consider forward voltage, reverse leakage, duty cycle, temperature, and switching stress together.

1N5822 pinout and polarity

An axial 1N5822 has two terminals. The unbanded lead is the anode (A), and the banded lead is the cathode (K).

For normal forward conduction, the anode is at a higher potential than the cathode. In reverse-blocking service, the cathode is at the higher potential. Do not infer polarity from the orientation of a product photograph; verify the physical band and the exact part marking.

1N5822 specifications with test conditions

The table keeps Vishay's current family datasheet separate from ST's legacy axial 1N5822 datasheet. These values are manufacturer-specific and should not be blended into a universal specification.

Why the forward-voltage value is often quoted incorrectly

The family tables contain several forward-voltage values. In both cited datasheets, 0.525 V is the maximum 1N5822 value at 3 A under the stated room-temperature pulse test. The lower 0.475 V value belongs to the 1N5820 column, not the 1N5822 column. A circuit's actual forward drop changes with current, junction temperature, waveform, and manufacturer.

What 3 A and 40 V really mean

The 3 A value is thermally conditioned. Vishay specifies it at a 95 deg C lead temperature with a defined lead length; legacy ST uses a 100 deg C lead temperature and a 0.5 duty cycle. Different lead length, copper area, airflow, ambient temperature, or waveform can produce a different junction temperature. Use the selected datasheet's derating curve and thermal model.

The 40 V VRRM value is a maximum repetitive peak reverse-voltage rating. It is not an instruction to operate continuously at 40 V. Check input tolerance, inductive ringing, switching overshoot, startup, and fault transients, then choose adequate voltage margin for the actual circuit.

Package and mechanical dimensions

Vishay's DO-201AD drawing specifies a body length of 7.2 mm to 9.5 mm, body diameter of 4.8 mm to 5.3 mm, lead diameter of 1.22 mm to 1.32 mm, and minimum straight lead length of 25.4 mm on each side. Lead forming, board spacing, and heat flow can all affect the installed result.

Lifecycle and manufacturer differences

ST marks its axial 1N5822 product page Obsolete - Out of Production. That status applies to ST's axial product, not automatically to every supplier using the 1N5822 base designation. Vishay maintains an official product page and family datasheet for its 1N5820/1N5821/1N5822 devices.

For maintenance work, record the manufacturer, complete ordering code, package, qualification level, and lifecycle status. For a new design, confirm current availability through an authorized supply channel and retain the chosen datasheet revision with the bill of materials.

Typical applications and selection checks

Manufacturer documentation identifies common uses such as low-voltage high-frequency inverter rectification, freewheeling paths, DC/DC converter outputs, reverse-polarity protection, switch-mode power-supply outputs, and low-voltage battery-charger power paths.

These are application categories, not ready-made circuits. For each design:

1. Identify the exact device. Record the manufacturer and full ordering suffix.

2. Measure reverse stress. Include tolerance, ringing, startup, load dump, and other transients.

3. Model the current waveform. Separate average, RMS, peak, and surge current.

4. Estimate forward loss. Use the datasheet curve at the expected current and junction temperature.

5. Estimate reverse loss. Use leakage data at the expected reverse voltage and temperature.

6. Close the thermal loop. Check lead temperature, mounting geometry, ambient temperature, and transient thermal impedance.

7. Check mechanics and polarity. Verify body dimensions, lead forming, clearances, and the cathode band.

8. Validate the circuit. Test worst-case line, load, temperature, startup, shutdown, and fault conditions.

How to compare possible 1N5822 replacements

A proposed device is not a drop-in replacement merely because it shares the 1N5822 name or appears in a distributor cross-reference. Compare the exact datasheets and verify VRRM, DC blocking voltage, average/RMS/peak current, surge waveform, forward-voltage curves, reverse leakage over temperature, junction limit, package dimensions, polarity, qualification, lifecycle, and supply source.

Within Vishay's axial family, 1N5820 and 1N5821 are rated for 20 V and 30 V VRRM. They cannot satisfy a design that genuinely requires the 1N5822's 40 V rating. A same-number device from another manufacturer may be a candidate for validation, but the 125 deg C versus 150 deg C junction-limit difference shows why the complete specifications must be compared.

Is LEO1N5822 the same as the axial 1N5822?

No. ST's LEO1N5822 is a rad-hard 3 A, 40 V Schottky rectifier in a SOD128Flat surface-mount package for low-earth-orbit and high-reliability systems. It is not the same mechanical product as ST's obsolete axial DO-201AD 1N5822. Package, qualification, radiation data, thermal behavior, and ordering information all differ.

FAQ

What is the 1N5822 pinout?

It is a two-terminal axial diode. The unbanded lead is the anode, and the banded lead is the cathode.

What are the main 1N5822 ratings?

For the cited Vishay device, the headline ratings are 40 V VRRM and 3 A IF(AV) in DO-201AD. The 3 A value is tied to a 95 deg C lead-temperature condition and a specified lead length.

What is the forward voltage of a 1N5822?

Vishay specifies a maximum instantaneous forward voltage of 0.525 V at 3 A and 25 deg C using a 300 us pulse at 1% duty cycle. Use the datasheet curve for other currents and temperatures.

Can a 1N5822 handle 3 A continuously?

Only when the selected manufacturer's mounting and thermal conditions keep the junction within its limit. The current rating cannot be separated from lead temperature, mounting, ambient conditions, and waveform.

What can replace a 1N5822?

No universal replacement is guaranteed. A candidate must meet the circuit's voltage, current, surge, loss, temperature, package, qualification, lifecycle, and sourcing requirements, then be validated in the actual application.

Is the ST 1N5822 still active?

ST marks its axial 1N5822 obsolete and out of production. Check other manufacturers separately; one supplier's lifecycle status does not define every device sold under the base number.

Is 1N5822 suitable for RF signal detection?

The cited 1N5822 documentation describes a power rectifier for power-conversion applications. RF detector circuits normally use small-signal devices selected for capacitance, impedance, frequency, and signal level. Do not infer RF suitability from the word Schottky alone.

Official sources

1. Vishay 1N5820, 1N5821, 1N5822 datasheet

2. Vishay 1N582x official product page

3. ST 1N5822 legacy datasheet

4. ST 1N5822 official product page

5. Vishay Design Guidelines for Schottky Rectifiers

6. ST LEO1N5822 official product page

7. ST LEO1N5822 datasheet