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

STMicroelectronics STPS340AFN

Name: STPS340AFN
Brand: STMicroelectronics
SKU: STPS340AFN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STPS340AFN

Manufacturer:: STMicroelectronics

Category:: Single Diodes

Package:: DO-221AC, SMA Flat Leads

Datasheet:: STPS340AFN.pdf

Description:: DIODE SCHOTTKY 40V 3A SMAFLAT

Quantity:: RFQ Add To RFQ list

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Inventory:9,271

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Product details

Overview

STPS340AFN from STMicroelectronics is a 40 V, 3 A surface-mount Schottky rectifier in SMA Flat Notch package, optimized for high-frequency DC-DC converters and switch-mode power supplies with low forward voltage (0.52 V typ. at 125 °C, 3 A) and low thermal resistance (20 °C/W junction-to-lead). It delivers negligible switching losses and avalanche-rated ruggedness for telecom and TV power supply applications.

For engineers reviewing the STPS340AFN datasheet, STPS340AFN pinout, STPS340AFN application, or STPS340AFN equivalent, this device is selected for low-conduction-loss rectification in compact, thermally constrained 40 V input rails where fast recovery, minimal reverse leakage (<2 mA at 125 °C), and ECOPACK2 compliance are critical.

Technical Context

The STPS340AFN employs a monolithic silicon Schottky barrier structure enabling near-zero reverse recovery charge and ultrafast switching-essential for >100 kHz SMPS topologies. Its low VF and low R_th(j-l) (20 °C/W) allow direct PCB copper conduction cooling without heatsinks in moderate-power designs.

Rated for 150 °C maximum junction temperature and avalanche energy of 90 W (10 µs pulse), it supports robust operation under transient overvoltage and surge conditions typical in AC/DC front-end and battery charger freewheeling paths.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	40 V - Maximum repetitive reverse blocking voltage; defines safe operating limit in 36 V nominal input systems.
I_F(AV)	3 A - Average forward current at T_L = 105 °C (SMA Flat Notch); sets continuous output capability in 12–24 V secondary-side rectification.
V_F(typ.)	0.52 V @ 125 °C, 3 A - Low conduction loss enables <1.6 W dissipation at full load, reducing thermal design burden.
R_th(j-l)	20 °C/W - Junction-to-lead thermal resistance; enables direct copper pad heat sinking on FR4 PCBs with ≥3.12 mm × 5.52 mm footprint.
I_FSM	105 A (10 ms sinusoidal) - Non-repetitive surge rating supports inrush and fault-current handling in offline adapters.
T_j(max)	150 °C - Maximum junction temperature; allows operation in sealed enclosures up to +85 °C ambient with proper layout.

Pinout & Package

STPS340AFN is housed in an SMA Flat Notch surface-mount package with cathode indicated by a band. The two-terminal device uses standard anode/cathode polarity and requires no biasing or control signals.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Input current entry point	Connected to switched node (e.g., MOSFET drain in buck sync rectifier or transformer secondary center-tap).
Cathode	Output current exit point	Connected to output capacitor and load; polarity must match circuit ground reference to prevent reverse conduction.

Key Features

Feature	Design Value
Low forward voltage drop	0.52 V typ. at 125 °C, 3 A - Reduces conduction loss by ~35% vs. comparable 40 V Si diodes, improving efficiency in 12–24 V outputs.
Avalanche rated	90 W repetitive peak avalanche power (10 µs, T_j = 125 °C) - Withstands voltage spikes during MOSFET turn-off without clamping diodes.
ECOPACK2 compliant	Lead-free, RoHS-compliant epoxy meeting UL94 V0 - Supports green manufacturing and global regulatory compliance without derating.
Extremely fast switching	Zero reverse recovery charge (Q_rr ≈ 0) - Eliminates switching loss and EMI associated with minority-carrier diode recovery in >200 kHz designs.

Applications

Telecom Power Supply

TV Power Supply

Use Scenario: Secondary-side rectification in 48 V input, 12 V/3 A isolated DC-DC modules for base station RF cards.

IC Role / Device Role / Timing Role: Freewheeling Schottky rectifier replacing synchronous MOSFETs where gate drive complexity is undesirable.

Use Value: Enables >92% efficiency at full load with no gate driver overhead and immunity to shoot-through failure modes.

Use Scenario: Output rectification in 36 V input, 24 V/2.5 A standby and main power rails of smart LED TVs.

IC Role / Device Role / Timing Role: Low-V_F output diode in flyback and LLC resonant converters operating at 65–130 kHz.

Use Value: Maintains <50 mV output ripple under dynamic load steps due to minimal stored charge and fast response.

Battery Charger

Set-Top Box Power Supply

Use Scenario: Polarity protection and OR-ing diode in dual-input (AC adapter + USB PD) Li-ion battery charging circuits.

IC Role / Device Role / Timing Role: Unidirectional current path preventing backfeed while supporting hot-swap insertion.

Use Value: 0.52 V V_F limits voltage drop to <1.6% of 20 V input, preserving charging headroom and minimizing thermal rise on compact PCBs.

Use Scenario: Input rectification in 12 V/1.8 A auxiliary supply for SoC and memory subsystems in cable/satellite receivers.

IC Role / Device Role / Timing Role: High-frequency bridge leg diode in half-wave doubler configuration feeding 3.3 V LDOs.

Use Value: Low R_th(j-l) (20 °C/W) allows direct thermal coupling to 2-layer FR4 copper, eliminating discrete thermal vias.

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 NSS40300PD1T1G	Same 40 V V_RRM, 3 A I_F(AV), but VF = 0.55 V @ 125 °C, 3 A; R_th(j-l) = 25 °C/W (SOD-123FL).	Slightly higher conduction loss and thermal resistance; suitable only where board space permits larger thermal pad or lower ambient.	Select when SOD-123FL footprint is standardized and 0.03 V V_F penalty is acceptable for sourcing continuity.
Vishay VS-3EWH04-M3/5BT	40 V V_RRM, 3 A I_F(AV), VF = 0.54 V @ 125 °C, 3 A; packaged in SMA (not Flat Notch); R_th(j-l) = 22 °C/W.	Standard SMA outline lacks flat notch; requires different stencil and placement alignment; identical electrical performance otherwise.	Choose for legacy SMA-compatible lines where footprint change is not feasible and 2 °C/W thermal penalty is tolerable.

Compared with NSS40300PD1T1G and VS-3EWH04-M3/5BT, STPS340AFN offers the lowest VF (0.52 V) and best thermal resistance (20 °C/W) in its class, making it optimal for space- and thermally constrained 3 A rectification where efficiency above 90% is mandatory.

Availability

STPS340AFN is available at Aetrix Electronics and suitable for telecom power supply, TV power supply, and battery charger designs requiring stable component supply, lead-free compliance, and consistent thermal performance across production batches.

Supply support for STPS340AFN 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, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.

The STPS series targets high-efficiency, high-reliability power conversion with Schottky rectifiers optimized for SMPS, DC-DC, and freewheeling applications where low VF, fast switching, and ruggedness are essential.

FAQ

What is the maximum allowable PCB copper area for thermal optimization of STPS340AFN?

The recommended footprint per Figure 18 is 3.12 mm × 5.52 mm (123 mil × 217 mil), with thermal performance scaling linearly up to ~200 mm² copper area per lead. At 100 mm², R_th(j-a) drops to ~35 °C/W on 35 µm FR4; doubling copper area further reduces thermal resistance by ~15%, per Figure 12.

Does STPS340AFN require a heatsink in standard 2-layer PCB layouts?

No heatsink is required. With its 20 °C/W R_th(j-l) and recommended 3.12 mm × 5.52 mm footprint, STPS340AFN dissipates ≤1.6 W at 3 A/125 °C junction temperature using only internal PCB copper. Thermal vias to inner ground planes further reduce R_th(j-a) but are optional for most 3 A applications.

How does the avalanche rating of STPS340AFN improve system reliability?

The 90 W repetitive avalanche power rating (10 µs, T_j = 125 °C) allows STPS340AFN to absorb transient voltage spikes-such as those from transformer leakage inductance or MOSFET turn-off-without catastrophic failure. This eliminates need for external snubbers in many flyback and forward converter designs.

Can STPS340AFN be used in parallel configurations for higher current?

Parallel operation is not recommended. Schottky diodes exhibit negative temperature coefficient of V_F, causing current imbalance under thermal gradients. For >3 A, ST recommends using STPS540AFN (5 A) or DPAK-packaged STPS340B-TR instead of paralleling SMA devices.

STPS340AFN Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: DO-221AC, SMA Flat Leads

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

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:: SMAflat Notch

Operating Temperature - Junction:: 150°C

STPS340AFN FAQ

1.How can I place an order for STPS340AFN through Aetrix?

Please submit a Request for Quotation (RFQ) for STPS340AFN 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 STPS340AFN reliable?

The price and inventory of STPS340AFN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STPS340AFN is usually 5 days.

3.What payment methods are accepted for STPS340AFN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STPS340AFN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STPS340AFN?

STPS340AFN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STPS340AFN 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 STPS340AFN?

For technical support, including STPS340AFN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STPS340AFN requirements.

6.How does Aetrix verify that STPS340AFN is sourced from the original manufacturer or authorized distributors?

All STPS340AFN 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 STPS340AFN meets industry standards.

7.What is the process for return or replacement of STPS340AFN?

All STPS340AFN units undergo pre-shipment inspection (PSI). If there is an issue with STPS340AFN, 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 STPS340AFN part is unused and in its original packaging.

Return procedure for STPS340AFN:

1.Submit a request within 90 days.

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

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