What Is a DFN Schottky Rectifier?

A DFN Schottky rectifier trades leakage for a 410 mV forward drop in a 0.37 mm package. What the package, the leakage and the copper under it decide.

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A DFN Schottky rectifier is bought for a number in the tens of millivolts and a package measured in tenths of a millimetre — and it is paid for in leakage. Take a real one: Nexperia’s PMEG2005EPK sits in a leadless DFN1608D-2 body 0.37 mm high, drops 410 mV maximum at 500 mA, and specifies 130 µA maximum of reverse leakage at just 10 V. Both halves of that sentence matter, and the leakage half is the one that decides whether the part belongs in your circuit.

Last updated: October 11, 2026

Key Takeaways

DFN stands for a leadless surface-mount package family. The die sits on an exposed pad, so the thermal path runs into the board rather than through leads.
The Schottky junction is a metal-semiconductor contact: low forward drop, fast turn-on, and effectively no minority-carrier recovery to speak of.
The trade is explicit. Lower forward voltage comes with higher reverse leakage, and leakage rises steeply with temperature.
The current rating is board-dependent. Manufacturers state the conditions — a ceramic PCB with a standard footprint, or a specified pad temperature — and less copper means less current.
Flat-lead power packages such as CFP15 exist for the same job at higher current, and some are qualified to AEC-Q101.

What the Package Actually Contributes

The electrical behaviour comes from the junction; the DFN package decides how much power you can put through it before the board gets hot. Those are separable, and it pays to keep them separate when specifying.

A leadless package places a thermal pad directly under the die and solders it to the board, which shortens the heat path and reduces the parasitic inductance that leaded packages introduce. That is why flat and leadless Schottky packages dominate low-voltage, high-frequency conversion stages: the device switches fast because it is a Schottky, and the loop stays quiet because the package does not add much inductance to it.

Package height is the second reason. The PMEG2005EPK is 0.37 mm high in a 1.6 × 0.8 mm outline — the kind of dimension that decides whether a wearable or a slim module can be built at all. For designs that need more current in the same style of package, the flat-lead power outline is the next step up: Nexperia’s PMEG030V030EPD is a 30 V, 3 A part in a CFP15 body only 0.78 mm high, using clip bonding and a heatsink pad, and it is qualified to AEC-Q101.

Three Real Parts, and What They Cost You

Manufacturer datasheets make the trade legible, so read them side by side. The three Nexperia devices below are all low-V_F Schottky rectifiers; the differences are package, current and how much leakage you accept in exchange for the forward drop.

Parameter (datasheet values)	PMEG2005EPK	PMEG4005EJ	PMEG030V030EPD
Package	DFN1608D-2 (SOD1608), leadless, 0.37 mm high	SC-90 (SOD323F) flat-lead, 1.7 × 1.25 × 0.7 mm	CFP15 (SOT1289) flat-lead power, 0.78 mm high
Reverse voltage V_R	20 V	40 V	30 V
Average forward current I_F(AV)	0.5 A (δ = 0.5, 20 kHz, on a ceramic PCB)	0.5 A (at T_sp ≤ 55 °C)	3 A (at T_sp ≤ 170 °C)
Forward voltage V_F (typ / max)	360 / 410 mV at 500 mA	420 / 470 mV at 500 mA	400 / 450 mV at 3 A
Reverse leakage	30 µA typ, 130 µA max at V_R = 10 V	not quoted at 10 V; leakage specified at rated conditions	45 µA typ, 150 µA max at V_R = 30 V
Repetitive peak forward / surge current	0.5 A average; surge rating as specified in the datasheet	7 A repetitive peak (1 ms, δ ≤ 0.25); 10 A non-repetitive (8 ms square)	3 A average with the package thermal path behind it
Reverse recovery	3 ns typical	Schottky behaviour, no minority-carrier recovery	Schottky behaviour with clip bonding for heat
Qualification note	Industrial datasheet	Industrial datasheet	AEC-Q101 qualified

The leakage column is the one that surprises people. A 130 µA maximum at 10 V is a real current in a battery-backed or very high-impedance node, and it is the direct consequence of engineering the barrier for a 360 mV forward drop. If the circuit is a charging path or a blocking diode on a solar input, leakage is a continuous loss; if it is a signal-level clamp, it may be irrelevant. Either way it is a design decision, not a footnote.

Where a DFN Schottky Belongs

The applications follow from low voltage, moderate current and a need for compactness. Switch-mode supply rectification and freewheeling in low-voltage rails, reverse-polarity and reverse-current blocking at an input, battery charging and power-path OR-ing, photovoltaic blocking diodes, and the freewheel path of a boost converter all suit the family.

Two duties it does not suit are worth naming, because both come up. High reverse voltage is the first: Schottky barriers generally do not extend much past the low hundreds of volts, so mains-side rectification belongs to a different device class. Very low leakage at high temperature is the second: where a circuit must hold a node with minimal current, a p-n device or a leakage-screened part is usually the better answer, even at the cost of forward drop.

The Two Numbers That Set the Current

The current rating is meaningless without its thermal condition, and the condition is board-specific.

Look at how the datasheets state it. The PMEG2005EPK quotes 0.5 A average at a 50 % duty cycle with a 20 kHz square wave on a ceramic printed-circuit board with a standard footprint, or at a solder-point temperature of 140 °C — two different ways of saying the same thing, both of which depend on how the part is mounted. The PMEG030V030EPD quotes 3 A at a solder-point temperature of 170 °C, which is only achievable because the flat-lead power package and its heatsink pad move heat into the board efficiently.

A worked estimate makes the sensitivity clear. Suppose the PMEG030V030EPD carries its rated 3 A and drops the specified 450 mV maximum at that current. Conduction loss is 3 A × 0.45 V = 1.35 W. That heat leaves through the solder point, so the interface between the package and the copper is where the design is won or lost: with a well-designed pad the solder point stays near the datasheet condition; with a minimal pad the same 1.35 W pushes the junction well past the temperature the 3 A rating assumes. This is a model with stated assumptions, not a measurement, but the direction is unambiguous — the copper area is part of the electrical specification.

FAQ

What is a DFN Schottky rectifier?

It is a Schottky diode in a leadless surface-mount package. The die sits on an exposed thermal pad instead of on leads, which gives a very low profile, short thermal path and low parasitic inductance, while the Schottky junction provides the low forward drop and fast switching.

Why does a low forward voltage diode leak so much?

Because the barrier height that produces the low forward drop also lets more carriers through in reverse. The two characteristics are linked by design, so a part specified at 410 mV maximum can specify 130 µA maximum of leakage at 10 V. Choose between them by asking which loss matters in your circuit.

Does leakage get worse when the part is hot?

Yes, markedly. Schottky leakage rises steeply with junction temperature, which is why the datasheet quotes it at a stated temperature and why the hot figure is the one to design against in an always-on or battery-backed node.

How do I know how much current a DFN Schottky can carry?

Read the condition attached to the rating. Manufacturers quote average current at a specified PCB, footprint or solder-point temperature, so the usable current depends on your copper area. If your pad is smaller than the condition the datasheet used, expect less current at the same junction temperature.

When should I move to a different package or technology?

Move to a flat-lead power package when the same style of part needs more current in a slightly thicker outline, and to a p-n, ultrafast or SiC device when the reverse voltage or the leakage requirement exceeds what a Schottky barrier can offer.

Official Resources

References

Nexperia, PMEG2005EPK — 20 V, 0.5 A low V_F Schottky barrier rectifier — source of the DFN1608D-2 leadless package, 0.37 mm height, 410 mV maximum forward voltage at 500 mA, 130 µA maximum leakage at 10 V, 3 ns reverse recovery and the ceramic-PCB current condition. assets.nexperia.com — PMEG2005EPK datasheet (PDF)
Nexperia, PMEG030V030EPD — 30 V, 3 A low V_F MEGA Schottky barrier rectifier — source of the CFP15 flat-lead package, 0.78 mm height, clip-bonding heat path, 450 mV maximum forward voltage at 3 A, 150 µA maximum leakage at 30 V and the AEC-Q101 qualification statement. assets.nexperia.com — PMEG030V030EPD datasheet (PDF)
Nexperia, PMEG4005EJ — 40 V, 0.5 A very low V_F MEGA Schottky barrier rectifier — source of the SC-90 (SOD323F) flat-lead package dimensions, 470 mV maximum forward voltage, the 7 A repetitive peak and 10 A non-repetitive current ratings and the power-dissipation figures. assets.nexperia.com — PMEG4005EJ datasheet (PDF)
STMicroelectronics, STPS20H100C — 100 V, 20 A power Schottky rectifier — comparison point for what a heat-sinked Schottky package adds in current capability and thermal resistance. st.com — STPS20H100C datasheet (PDF)

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