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DO-41 · 1N5819
ActiveSchottky Rectifier (40V/1A)
1N5819
Vishay · DO-41 · Schottky Rectifier (40V/1A)
Price on Request
Get a competitive quote within 24 hours. Volume discounts available. Shenzhen stock ships in 1-2 business days.
Overview
The 1N5819 is the 40 V member of Vishay's 1N5817 to 1N5819 Schottky barrier rectifier family, built on a metal-semiconductor junction rather than a PN junction. Because conduction is by majority carriers there is no stored minority charge and therefore no reverse-recovery current — the device simply stops conducting when the voltage reverses, which is why it is the default axial diode for high-frequency rectification, freewheeling and polarity protection below 40 V. An integrated guard ring provides overvoltage protection, and the package is the familiar DO-41 (DO-204AL) axial with a 0.332 g body on 13 inch reels of 5,500 pcs.
The numbers that matter in a design review: VRRM and VDC are 40 V with 28 Vrms and a 48 V non-repetitive reverse surge rating; average forward current is 1.0 A at 9.5 mm lead length and TL = 90 °C; maximum instantaneous forward voltage is 0.600 V at 1.0 A and 0.900 V at 3.1 A on a 300 µs pulse test; peak forward surge is 25 A for an 8.3 ms half sine; dV/dt is 10,000 V/µs; thermal resistance is 50 °C/W junction-to-ambient and 15 °C/W junction-to-lead; and the junction range is -65 °C to +125 °C. Typical junction capacitance is 110 pF at 4 V and 1 MHz.
Reverse leakage is the price you pay for the low forward drop. Vishay guarantees a maximum average reverse current of 1.0 mA at rated DC blocking voltage and 25 °C, rising to 10 mA at 100 °C. At 40 V that hot leakage alone is 0.4 W of dissipation, and Schottky leakage roughly doubles every 10 °C, which can set up a thermal runaway loop in a warm, poorly ventilated enclosure. Keep a healthy voltage margin (do not run a 40 V part on a 36 V rail), give the leads copper, and derate the current at temperature rather than relying on the 1.0 A headline.
Sourcing is easy and that is precisely why the 1N5819 is one of the most remarked discrete parts in the market. The classic fraud is a 1N5817 (20 V) or 1N5818 (30 V) with the marking altered, or a small-die clone that passes a room-temperature forward-drop check and then leaks heavily when hot. Screen lots by measuring VF at 1 A (must stay below 0.600 V), then reverse-biasing at 40 V and measuring leakage cold and at 85 °C to 100 °C, checking body dimensions and weight, and wiping the marking with solvent. Authorized Vishay 1N5819-E3/54 stock in Shenzhen ships in 1 to 2 days; second sources from Diodes Incorporated, MCC, Rectron, MDD and other Asian fabs are pin- and spec-compatible.
Key Features
- 40 V VRRM / 28 Vrms with a 48 V non-repetitive reverse surge rating
- 0.600 V maximum forward drop at 1.0 A — roughly half of a 1N4007
- Schottky majority-carrier device: no reverse-recovery charge, 10,000 V/µs dV/dt
- Guard-ring protected, 25 A 8.3 ms surge, 125 °C junction, DO-41 axial
- Leakage is the limit: 1.0 mA max at 25 °C and 10 mA at 100 °C
Typical Applications
- Output rectification in low-voltage switch-mode and DC-DC converters
- Freewheeling across relays, DC motors, solenoids and buck inductors
- Reverse-polarity and OR-ing protection on 12 V to 24 V rails
- Solar panel bypass and battery-charger blocking duty
- Higher-current RF detection, clamping and logic steering
Specifications
- Repetitive Peak Reverse Voltage (VRRM)
- 40 V
- Average Forward Rectified Current (IF(AV), 9.5 mm Lead Length, TL = 90 °C)
- 1.0 A
- Peak Forward Surge Current (IFSM, 8.3 ms Half Sine)
- 25 A
- Maximum Instantaneous Forward Voltage (VF at 1.0 A)
- 0.600 V
- Maximum Average Reverse Current (IR at Rated VDC, 25 °C)
- 1.0 mA
- Maximum Average Reverse Current (IR at Rated VDC, 100 °C)
- 10 mA
- Reverse Recovery Time
- None (Schottky, Majority Carrier)
- Operating Junction Temperature
- -65 to +125 °C
- Pins
- 2
- RoHS
- Compliant
Procurement Tips
Require hot reverse-leakage test data (IR at 40 V, 100 °C) on any 1N5819 lot bought through a broker — remarked 1N5817 and 1N5818 parts look identical, pass a cold check, and only fail once the enclosure is warm.
Frequently Asked Questions
1N5819 versus 1N4007 — which do I use?
They solve different problems. The 1N5819 is a 40 V Schottky with a 0.6 V drop and no recovery charge, ideal for high-frequency, low-voltage rectification. The 1N4007 is a 1000 V silicon rectifier with a 1.1 V drop and ~30 µs recovery, meant for line-frequency work. Never put a 1N5819 on a mains bridge, and never put a 1N4007 on a fast switching node.
Why does my 1N5819 get warm with almost no load current?
Reverse leakage. It is specified at up to 1.0 mA at 25 °C and 10 mA at 100 °C across 40 V, which is up to 0.4 W of dissipation in a hot enclosure. If a device runs hot at low load, suspect excessive reverse voltage, high ambient, or a remarked 1N5817/1N5818 with worse hot leakage.
Can I replace the 1N5819 with an SS14 or SS34?
An SS14 (40 V, 1 A, SMA) is the surface-mount equivalent and drops in electrically; an SS34 (40 V, 3 A) is a comfortable uprate if the pad layout can handle the larger package. Check VF and hot IR per vendor datasheet, since Schottky characteristics vary more between fabs than silicon rectifier characteristics do.
How fast can the 1N5819 switch?
There is no stored charge, so the limit is junction capacitance (110 pF typical at 4 V) and package inductance. It rectifies cleanly from tens of kilohertz up into the low megahertz range, far beyond a standard-recovery silicon rectifier.
Is the 1N5819 suitable for a 48 V rail?
No. At 40 V VRRM there is no margin for transients on a 48 V bus. Move to a higher-voltage Schottky such as the SR560 or SS56 (both 60 V, 5 A), or a 100 V device such as the MBR10100 for higher-voltage buses.
How do I detect a remarked 1N5819?
Measure VF at 1.0 A (genuine parts stay below 0.600 V), then reverse-bias at 40 V and record leakage at 25 °C and again at 85 °C to 100 °C — remarked 1N5817 and 1N5818 devices often pass cold and fail hot. Also verify the DO-41 body length, the 0.332 g weight, matte-tin leads and marking that survives a solvent wipe.
What are the MOQ and lead times?
MOQ is one reel of 5,500 pcs for 1N5819-E3/54, or 100 pcs loose for prototyping. Shenzhen stock ships in 1 to 2 days; the authorized Vishay channel takes 4 to 8 weeks, and second sources from Diodes Inc, MCC, Rectron and MDD are usually available sooner.
Alternatives & Equivalents
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