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Home > Products > Discrete Semiconductor Products > Diodes > Rectifiers > Single Diodes

STMicroelectronics STPS340U

Name: STPS340U
Brand: STMicroelectronics
SKU: STPS340U
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STPS340U

Manufacturer:: STMicroelectronics

Category:: Single Diodes

Package:: DO-214AA, SMB

Datasheet:: STPS340U.pdf

Description:: DIODE SCHOTTKY 40V 3A SMB

Quantity:: RFQ Add To RFQ list

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Inventory:34,658

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Product details

Overview

STPS340U from STMicroelectronics is a 40 V, 3 A surface-mount Schottky rectifier in SMB package, featuring low forward voltage drop (0.52 V at 125 °C, 3 A), low thermal resistance (25 °C/W junction-to-lead), and avalanche rating for robustness in high-frequency DC–DC converters and telecom power supplies.

For engineers reviewing the STPS340U datasheet, STPS340U pinout, STPS340U application, or STPS340U equivalent, key selection criteria include forward voltage at elevated temperature, thermal resistance under real PCB copper conditions, avalanche energy handling (90 W, 10 µs), and SMB footprint compatibility with automated assembly.

Technical Context

This Schottky rectifier uses a planar silicon structure optimized for minimal conduction loss and negligible reverse recovery charge, enabling operation up to several MHz without switching loss penalties. Its low VF and fast switching are achieved without a PN junction, eliminating minority-carrier storage delay.

The device is rated for 150 °C maximum junction temperature and supports surge currents up to 75 A (non-repetitive, 10 ms sinusoidal) in SMB package. Thermal performance depends on PCB copper area - R_th(j-a) drops from ~50 °C/W (no copper) to ~25 °C/W with 100 cm² per lead, per Figure 13.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	40 V - Maximum repetitive reverse blocking voltage; defines safe operating range in 36 V nominal bus applications.
I_F(AV)	3 A at T_L = 95 °C - Continuous average forward current limit under SMB package thermal constraints on standard FR4 board.
V_F(typ.)	0.52 V at 125 °C, 3 A - Directly determines conduction loss (P ≈ 0.42×I_F(AV) + 0.050×I_F(RMS)²) in SMPS output stages.
R_th(j-l)	25 °C/W - Junction-to-lead thermal resistance in SMB package; enables accurate thermal modeling when soldered to copper pour.
I_FSM	75 A (10 ms sinusoidal) - Peak non-repetitive surge capability; supports inrush and fault-current tolerance in AC/DC front-ends.
P_ARM	90 W (10 µs pulse, T_j = 125 °C) - Avalanche-rated power handling; ensures survivability during transient overvoltage events.
T_j(max)	150 °C - Maximum junction temperature; sets upper boundary for thermal design margin in sealed or high-ambient environments.

Pinout & Package

SMB package: surface-mount, 2-terminal, cathode-banded case. Dimensions: 3.30–3.95 mm × 5.10–5.60 mm × 1.90–2.45 mm height. UL94 V0 epoxy, lead-free, ECOPACK2 compliant.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Forward current entry point	Connected to lower-potential node (e.g., switch node in synchronous buck); requires low-inductance layout to minimize ringing.
Cathode	Forward current exit / reverse-blocking terminal	Marked by band; ties to output rail or ground return; must maintain clean, low-impedance path to reduce EMI and thermal rise.

Key Features

Feature	Design Value
Low forward voltage drop	0.52 V typ. at 125 °C, 3 A - Reduces conduction loss by >25% vs. comparable 45 V Schottkys, improving efficiency in 5–12 V output rails.
Avalanche energy rating	90 W peak (10 µs, T_j = 125 °C) - Enables reliable operation without external clamping in flyback snubberless designs or input surge scenarios.
Extremely fast switching	No reverse recovery charge (Q_rr ≈ 0) - Eliminates switching loss and associated EMI in >500 kHz DC–DC converters; no need for snubbers.
Low thermal resistance	R_th(j-l) = 25 °C/W (SMB) - Allows direct thermal coupling to PCB copper; achieves 3 A continuous rating with modest heatsinking (≥25 cm² per lead).
ECOPACK2 compliance	Lead-free, RoHS-compliant, halogen-free epoxy - Meets industrial and consumer environmental mandates without derating or process change.

Applications

Telecom Power Supply

Set-Top Box Power Supply

Use Scenario: Secondary-side rectification in 48 V–12 V isolated DC–DC modules powering baseband processors and RF front-ends.

IC Role / Device Role / Timing Role: Output synchronous rectifier replacement; conducts during low-side MOSFET on-time in active-clamp forward topology.

Use Value: 0.52 V V_F at 125 °C reduces output stage loss by 0.39 W vs. legacy 0.65 V diodes, directly improving system efficiency and thermal headroom.

Use Scenario: 5 V/3.3 V standby and main rail rectification in multi-output flyback converters with tight space constraints.

IC Role / Device Role / Timing Role: Low-loss freewheeling diode in discontinuous conduction mode (DCM) operation; handles peak currents up to 75 A during startup surges.

Use Value: Avalanche rating (90 W, 10 µs) prevents failure during cold-swap or capacitor inrush, eliminating need for redundant TVS protection.

TV Power Supply

Battery Charger

Use Scenario: 19 V/24 V auxiliary rail rectification in LED-backlit LCD TV power boards operating at ambient up to 70 °C.

IC Role / Device Role / Timing Role: Polarity protection and freewheeling diode in boost PFC pre-regulator output stage.

Use Value: R_th(j-l) = 25 °C/W enables stable 3 A operation with only 50 cm² of 35 µm copper per lead - compatible with compact double-sided PCB layouts.

Use Scenario: Output rectification in 12 V/2 A wall-adapters for Li-ion battery packs with USB PD negotiation.

IC Role / Device Role / Timing Role: High-frequency rectifier in quasi-resonant flyback secondary; switches at 65–100 kHz with zero-voltage turn-off.

Use Value: Near-zero Q_rr eliminates reverse recovery spikes, reducing EMI filter component count and passing CISPR-32 Class B with margin.

Equivalent & Alternatives

The following parts are listed as comparable options for similar Schottky rectifier applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
ON Semiconductor SB340	V_F = 0.55 V (typ., 125 °C, 3 A); R_th(j-l) = 30 °C/W (SMB); no avalanche rating specified.	Lacks documented avalanche energy handling; unsuitable for unclamped inductive transients or surge-prone inputs.	Prefer STPS340U where transient robustness or thermal margin below 25 °C/W is required.
Vishay VSSAF340-M3/5AT	V_F = 0.54 V (typ., 125 °C, 3 A); R_th(j-l) = 27 °C/W; avalanche rated to 75 W (10 µs).	Lower avalanche energy (75 W vs. 90 W); slightly higher thermal resistance limits max current in thermally constrained layouts.	Acceptable where 15 W lower avalanche margin is acceptable and footprint matches SMB mechanical envelope.

Compared with SB340 and VSSAF340-M3/5AT, STPS340U delivers superior thermal performance (25 °C/W), highest avalanche energy (90 W), and lowest V_F at elevated temperature - making it optimal for high-reliability, high-density, or thermally limited 40 V rectification tasks.

Availability

STPS340U is available at Aetrix Electronics and suitable for telecom power supply, set-top box power supply, and TV power supply requiring stable component supply, consistent SMB footprint compatibility, and long-term industrial lifecycle support.

Supply support for STPS340U includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The STPS series targets high-efficiency, high-reliability power conversion - specifically engineered for Schottky rectification in SMPS, DC–DC converters, and freewheeling applications demanding low V_F, fast switching, and rugged avalanche behavior.

FAQ

What is the maximum continuous forward current for STPS340U at 70 °C ambient?

At 70 °C ambient temperature with standard FR4 PCB (no added heatsink), STPS340U supports approximately 2.6 A continuous forward current in SMB package, based on Figure 2's derating curve (δ = 0.5, SMB). This assumes ≥25 cm² copper per lead and natural convection cooling.

Does STPS340U require a heatsink in typical 3 A applications?

No dedicated heatsink is required. With ≥50 cm² of 35 µm copper per lead on FR4, R_th(j-a) drops to ~30 °C/W, allowing 3 A operation at T_L = 95 °C (per datasheet condition). Layout optimization - not external heatsinks - is the primary thermal strategy.

How does the avalanche rating of STPS340U improve system reliability?

The 90 W avalanche rating (10 µs, T_j = 125 °C) allows STPS340U to absorb transient overvoltages - such as those caused by transformer leakage inductance or sudden load removal - without failure. This eliminates need for parallel TVS diodes in many flyback and forward converter designs.

Can STPS340U replace older STPS340 variants like STPS340AFN?

Yes, but only in SMB footprint designs. STPS340U (SMB) and STPS340AFN (SMA Flat Notch) share identical electrical specs but differ mechanically: SMA has smaller footprint (2.25–2.90 mm × 5.00–5.35 mm) and higher R_th(j-l) (20 °C/W). Pin-to-pin replacement requires PCB redesign.

STPS340U Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: DO-214AA, SMB

Packaging:: Tape & Reel (TR)

Product Status:: Active

Technology:: Schottky

Voltage - DC Reverse (Vr) (Max):: 40 V

Current - Average Rectified (Io):: 3A

Voltage - Forward (Vf) (Max) @ If:: 630 mV @ 3 A

Speed:: Fast Recovery =< 500ns, > 200mA (Io)

Reverse Recovery Time (trr):: -

Current - Reverse Leakage @ Vr:: 20 µA @ 40 V

Capacitance @ Vr, F:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SMB

Operating Temperature - Junction:: 150°C (Max)

STPS340U FAQ

1.How can I place an order for STPS340U through Aetrix?

Please submit a Request for Quotation (RFQ) for STPS340U on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for STPS340U reliable?

The price and inventory of STPS340U are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STPS340U is usually 5 days.

3.What payment methods are accepted for STPS340U?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STPS340U transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STPS340U?

STPS340U orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STPS340U order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for STPS340U?

For technical support, including STPS340U datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STPS340U requirements.

6.How does Aetrix verify that STPS340U is sourced from the original manufacturer or authorized distributors?

All STPS340U products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that STPS340U meets industry standards.

7.What is the process for return or replacement of STPS340U?

All STPS340U units undergo pre-shipment inspection (PSI). If there is an issue with STPS340U, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The STPS340U part is unused and in its original packaging.

Return procedure for STPS340U:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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