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

STMicroelectronics STPS140AFN

Name: STPS140AFN
Brand: STMicroelectronics
SKU: STPS140AFN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: STPS140AFN

Manufacturer:: STMicroelectronics

Category:: Single Diodes

Package:: DO-221AC, SMA Flat Leads

Datasheet:: STPS140AFN.pdf

Description:: DIODE SCHOTTKY 40V 1A SMAFLAT

Quantity:: RFQ Add To RFQ list

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Inventory:4,330

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Product details

Overview

STPS140AFN from STMicroelectronics is a 40 V, 1 A surface-mount Schottky rectifier in SMA Flat Notch package, optimized for low forward voltage drop (0.43 V at 1 A, 125 °C), negligible switching losses, and avalanche-rated operation. It serves as a high-efficiency freewheeling diode or reverse polarity protection device in TV power supplies, set-top box DC-DC converters, and battery charger circuits.

For engineers reviewing the STPS140AFN datasheet, STPS140AFN pinout, STPS140AFN application, or STPS140AFN equivalent, key selection criteria include its 0.43 V typical VF at 125 °C, 150 °C max junction temperature, 60 A non-repetitive surge rating, ECOPACK2 compliance, and thermal resistance of 20 °C/W (junction-to-lead) - critical for compact, thermally constrained SMPS designs.

Technical Context

The STPS140AFN employs a single-chip planar Schottky barrier structure with metal–semiconductor junction optimized for high-frequency rectification. Its low VF and near-zero reverse recovery charge enable minimal conduction and switching losses in DC-DC converters operating above 100 kHz.

Designed for surface-mount assembly on FR4 PCBs, it leverages thermal conduction via leads (R_th(j-l) = 20 °C/W) and supports avalanche energy handling up to 65 W (10 µs pulse, T_j = 125 °C), making it suitable for inductive load commutation and transient overvoltage clamping without external snubbers.

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 input systems.
I_F(AV)	1 A - Average forward current at T_L = 135 °C; enables continuous operation in compact 5–12 V output rails.
V_F(typ)	0.43 V @ 1 A, 125 °C - Low conduction loss reduces power dissipation to ~430 mW, easing thermal design.
I_FSM	60 A - Non-repetitive surge current (10 ms sine); withstands inrush and fault transients in consumer power supplies.
R_th(j-l)	20 °C/W - Junction-to-lead thermal resistance; allows direct PCB copper pad heat sinking without heatsink.
T_j(max)	+150 °C - Maximum junction temperature; supports operation in sealed enclosures with ambient up to 85 °C.
ECOPACK2	Compliant - Halogen-free, RoHS-compliant packaging meeting stringent environmental requirements for global consumer electronics.

Pinout & Package

STPS140AFN is housed in an SMA Flat Notch surface-mount package with cathode indicated by a band. The two-terminal device has no internal connections beyond anode and cathode.

Pin/Terminal	Circuit Role	Design Meaning
Anode	Current entry point under forward bias	Connected to lower-potential side (e.g., switch node or ground return) in freewheeling configuration.
Cathode	Current exit point under forward bias; marked by notch/band	Connected to higher-potential rail (e.g., output capacitor positive) - polarity must be verified during layout.

Key Features

Feature	Design Value
Avalanche-rated operation	65 W peak avalanche power (10 µs, T_j = 125 °C) - enables robustness against inductive kickback without external clamping.
Low thermal resistance	R_th(j-l) = 20 °C/W - facilitates efficient heat transfer through PCB copper, reducing need for thermal vias or large pads.
High-frequency suitability	Negligible reverse recovery charge (Q_rr ≈ 0) - eliminates switching loss and EMI in >200 kHz DC-DC topologies.
Miniature SMT footprint	SMA Flat Notch (3.12 × 5.52 mm) - saves board space vs. standard SMA while maintaining mechanical stability.

Applications

TV Power Supply

Set-Top Box DC-DC Converter

Use Scenario: Secondary-side synchronous rectification and output freewheeling in 12 V/24 V isolated flyback supplies.

IC Role / Device Role / Timing Role: Freewheeling Schottky rectifier replacing slower PN diodes to reduce conduction loss and improve efficiency.

Use Value: 0.43 V VF at 125 °C cuts conduction loss by ~35% vs. comparable 0.65 V diodes, directly improving 12 V rail efficiency by 1.2–1.8%.

Use Scenario: Input reverse polarity protection and output rectification in multi-rail buck-derived power modules.

IC Role / Device Role / Timing Role: Unidirectional current path enforcer and low-loss output rectifier in 5 V/3.3 V point-of-load stages.

Use Value: 1 A average current rating with 150 °C T_j(max) ensures reliable operation under sustained 70 °C ambient in enclosed chassis.

Battery Charger Output Stage

Reverse Polarity Protection Circuit

Use Scenario: Output rectification in 5–9 V USB PD-compatible chargers with foldback current limiting.

IC Role / Device Role / Timing Role: Primary output rectifier handling pulsed 1–2 A loads with high duty-cycle ripple current.

Use Value: 60 A I_FSM withstands repeated 2 A inrush events during hot-plug, extending reliability beyond 10,000 cycles.

Use Scenario: Series-connected protection diode in 5–12 V input rails for embedded media players and smart remotes.

IC Role / Device Role / Timing Role: Passive polarity guard preventing damage from incorrect adapter insertion.

Use Value: 0.43 V VF minimizes voltage drop across protection path, preserving ≥4.75 V at 1 A for 5 V logic rails.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MBR140SFT1G	Same 40 V / 1 A rating; VF = 0.52 V @ 1 A, 25 °C; R_th(j-l) = 25 °C/W; SMB package	Higher VF increases conduction loss by ~180 mW at 1 A; larger SMB footprint requires more board area	Select when SMB compatibility or ON Semiconductor supply chain alignment is required.
SS14	40 V / 1 A; VF = 0.55 V @ 1 A, 25 °C; no avalanche rating; SMA package	Lacks avalanche energy rating (65 W) and has higher VF - unsuitable for inductive freewheeling with transients	Acceptable only in low-stress, non-inductive reverse polarity protection where surge immunity is not required.

Compared with MBR140SFT1G and SS14, STPS140AFN delivers superior thermal performance (20 °C/W vs. ≥25 °C/W), lower VF at elevated temperature, and certified avalanche capability - making it the preferred choice for thermally dense, high-reliability consumer power supplies.

Availability

STPS140AFN is available at Aetrix Electronics and suitable for TV power supplies, set-top box DC-DC converters, and battery charger designs requiring stable component supply, long-term lifecycle support, and consistent ECOPACK2-compliant manufacturing.

Supply support for STPS140AFN 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 microcontrollers, power devices, sensors, and analog ICs for automotive, industrial, and consumer markets.

The STPS140 series belongs to ST's high-efficiency Schottky rectifier product line, engineered specifically for low-voltage, high-frequency switched-mode power conversion in space-constrained consumer electronics.

FAQ

What is the cathode marking method on STPS140AFN?

The cathode is identified by a flat notch on one end of the SMA Flat Notch package body, aligned with the cathode terminal. This marking is visible under magnification and matches the recommended footprint orientation in DS1044 Figure 16. No silkscreen or ink mark is used - mechanical feature only.

Can STPS140AFN replace STPS140A in existing designs?

Yes, STPS140AFN is a direct functional replacement for STPS140A with identical electrical specs and thermal performance. The SMA Flat Notch package offers improved mechanical stability and slightly lower weight (39 mg vs. 68 mg), but requires updated stencil and placement settings due to different outline and notch-based polarity alignment.

Is STPS140AFN suitable for automotive applications?

No - STPS140AFN is not qualified to AEC-Q101 and lacks automotive-grade screening, extended temperature validation (-40 to +150 °C full-range characterization), or PPAP documentation. It is rated for commercial/industrial use only (T_amb ≤ 85 °C per derating curves), and should not be deployed in automotive ECUs or infotainment power supplies.

How does the 20 °C/W R_th(j-l) translate to PCB layout requirements?

A 20 °C/W R_th(j-l) means that with 1 A DC current (0.43 W dissipation), junction-to-lead temperature rise is ~8.6 °C. To maintain T_j ≤ 150 °C at 85 °C ambient, minimum copper area per lead is 120 mm² (per DS1044 Figure 12), achievable with 1.2 mm wide × 10 mm long thermal pads connected to inner-layer planes via ≥4 vias.

STPS140AFN 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):: 1A

Voltage - Forward (Vf) (Max) @ If:: 550 mV @ 1 A

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

Reverse Recovery Time (trr):: -

Current - Reverse Leakage @ Vr:: 12 µA @ 40 V

Capacitance @ Vr, F:: -

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SMAflat Notch

Operating Temperature - Junction:: 150°C

STPS140AFN FAQ

1.How can I place an order for STPS140AFN through Aetrix?

Please submit a Request for Quotation (RFQ) for STPS140AFN 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 STPS140AFN reliable?

The price and inventory of STPS140AFN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for STPS140AFN is usually 5 days.

3.What payment methods are accepted for STPS140AFN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for STPS140AFN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for STPS140AFN?

STPS140AFN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your STPS140AFN 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 STPS140AFN?

For technical support, including STPS140AFN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your STPS140AFN requirements.

6.How does Aetrix verify that STPS140AFN is sourced from the original manufacturer or authorized distributors?

All STPS140AFN 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 STPS140AFN meets industry standards.

7.What is the process for return or replacement of STPS140AFN?

All STPS140AFN units undergo pre-shipment inspection (PSI). If there is an issue with STPS140AFN, 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 STPS140AFN part is unused and in its original packaging.

Return procedure for STPS140AFN:

1.Submit a request within 90 days.

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

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