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STMicroelectronics STPS340U — Discrete Semiconductors

STPS340U Schottky Diode, 40 V 3 A, SMB, Active

MPNSTPS340U
Active

STMicroelectronics STPS340U Schottky rectifier, 40 V reverse, 3 A forward, fast recovery ≤500 ns, 630 mV Vf at 3 A, SMB surface-mount package, active production.

$0.4200Ref. price · indicative, final on quote
STMicroelectronics STPS340U datasheet (PDF)
PackagingDO-214AA, SMB
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

STPS340U specifications
ParameterValue
Diode typeSchottky
MountingSurface Mount
Voltage - DC reverse (Vr)40 V
Voltage - forward (Vf) (Max) @ if630 mV @ 3 A
Current - reverse leakage @ vr20 µA @ 40 V
Current - average rectified3A
Operating temperature - junction150°C(Max)
SpeedFast Recovery =< 500ns, > 200mA (Io)
PackageTape & Reel (TR); Cut Tape (CT)
CaseDO-214AA, SMB

Product details

The fast recovery characteristic (≤500 ns at >200 mA) means the diode switches off cleanly in a continuous-conduction-mode flyback or forward converter, reducing reverse-recovery losses compared to a standard rectifier. This matters most when the switching frequency is above 50 kHz — the recovery charge is small enough that snubber requirements are minimal.

Current, voltage, and thermal budget

At 3 A continuous, the SMB package dissipates roughly 1.9 W (3 A × 0.63 V). The 20 µA reverse leakage at 40 V is a room-temperature number; at 100 °C junction, expect leakage to dominate the thermal budget if the board is in a confined enclosure. The 40 V reverse rating provides a 16 V margin over a 24 V rail, which is adequate for most industrial and telecom supplies. For a 48 V bus, this part is not suitable — look at the STPS5H100 or similar 100 V Schottky in the same SMB footprint.

No last-time-buy, no PCN for obsolescence.

Frequently asked questions

Can STPS340U replace SS34?

The SS34 is a 40 V, 3 A Schottky in an SMA package. The STPS340U is in an SMB package (DO-214AA), which is slightly larger but pin-compatible with the SMA footprint on most boards. The electrical ratings are equivalent: 40 V reverse, 3 A forward. The STPS340U has a lower typical Vf (630 mV vs 0.5 V for SS34 at 3 A), so conduction losses are slightly higher. The SMB package offers better thermal dissipation than SMA. For a drop-in replacement, check the PCB pad geometry — SMB pads are wider than SMA, so a direct solder-paste stencil match may need verification.