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

Taiwan Semiconductor Corporation SF31G-A

Name: SF31G-A
Brand: Taiwan Semiconductor Corporation
SKU: SF31G-A
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SF31G-A

Manufacturer:: Taiwan Semiconductor Corporation

Category:: Single Diodes

Package:: DO-201AD, Axial

Datasheet:: SF31G-A.pdf

Description:: 35NS, 3A, 50V, SUPER FAST RECOVE

Quantity:: RFQ Add To RFQ list

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Inventory:9,666

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Product details

Overview

SF31G-A from Taiwan Semiconductor is a 3A, 50V super fast rectifier diode in DO-201AD package, featuring 0.95V forward voltage at 3A and 35ns reverse recovery time, used in DC-DC converters and switching-mode power supplies for high-efficiency freewheeling and output rectification.

For engineers reviewing the SF31G-A datasheet, SF31G-A pinout, SF31G-A application, or SF31G-A equivalent, key selection criteria include V_RRM = 50V, I_F = 3A, t_rr = 35ns, V_F = 0.95V @ 3A, and DO-201AD thermal performance (R_θJL = 10°C/W).

Technical Context

The SF31G-A is a single-die, silicon planar super fast recovery rectifier optimized for high-frequency switching applications. Its 35ns reverse recovery time and low 0.95V forward voltage at rated current enable reduced switching losses and improved efficiency in SMPS topologies.

Thermal design is supported by a junction-to-lead resistance of 10°C/W and a maximum junction temperature of +150°C. The device uses pure tin-plated leads compliant with J-STD-002 and passes JESD 201 Class 1A whisker testing.

Key Specifications

Parameter	Value and Actual Design Meaning
V_RRM	50 V - Maximum repetitive reverse voltage before breakdown; sets safe operating limit in 50V-output DC-DC stages.
I_F	3 A - Continuous average forward current; defines steady-state conduction capability in primary/secondary-side rectification.
t_rr	35 ns - Reverse recovery time; enables stable operation up to ~3–5 MHz switching frequencies with minimal tail current loss.
V_F	0.95 V @ 3A, 25°C - Forward voltage drop; determines conduction loss (2.85 W max at full load) and thermal rise in compact layouts.
R_θJL	10 °C/W - Junction-to-lead thermal resistance; allows direct heatsinking via PCB copper pour or lead-frame thermal path.
I_FSM	125 A - Non-repetitive surge current (8.3 ms half-sine); withstands startup inrush and transient overloads without failure.

Pinout & Package

Package: DO-201AD - Axial-leaded, molded plastic case with cathode band marking; UL 94V-0 rated compound; 1.10g mass; compatible with wave and reflow soldering per J-STD-002.

Pin/Terminal	Circuit Role	Design Meaning
Anode (Lead 1)	Forward current entry point	Connected to lower-potential node (e.g., switch node or ground return); requires adequate trace width for 3A continuous flow.
Cathode (Lead 2, banded end)	Forward current exit / reverse blocking terminal	Connected to higher-potential rail (e.g., output bus); polarity must be observed to prevent catastrophic short during reverse bias.

Key Features

Feature	Design Value
Super fast recovery	35 ns t_rr enables high-frequency SMPS operation with low switching loss and minimal EMI generation.
Low forward voltage	0.95 V @ 3A reduces conduction loss by ~15–20% vs. standard fast rectifiers, improving thermal margin in sealed enclosures.
High surge robustness	125 A I_FSM supports reliable cold-start and overload handling in industrial 24V/48V DC systems.
RoHS & halogen-free	Complies with IEC 61249-2-21; suitable for automotive and medical-adjacent equipment requiring green material declarations.

Applications

DC-DC Converter Output Rectification	Switching Mode Inverter Freewheeling
Use Scenario: Secondary-side synchronous or diode rectification in isolated 5–24V buck-derived DC-DC modules. IC Role / Device Role / Timing Role: Unidirectional current valve providing low-loss output conduction and fast reverse blocking during transformer reset. Use Value: 0.95V V_F minimizes power loss at 3A load; 35ns t_rr prevents cross-conduction in phase-shifted topologies.	Use Scenario: Freewheeling path across inductive loads (e.g., motor windings, solenoids) in H-bridge inverters. IC Role / Device Role / Timing Role: Clamp-induced back-EMF spikes and recirculate stored inductive energy during PWM off-time. Use Value: 125A I_FSM safely absorbs repetitive inductive kickback; DO-201AD mechanical robustness ensures long-term reliability under vibration.
AC-DC Adapter Secondary Rectification	Industrial 24V Power Supply Input Stage
Use Scenario: Output rectification in universal-input 5V/12V/24V AC-DC adapters with <100 kHz flyback operation. IC Role / Device Role / Timing Role: Converts transformer secondary AC to regulated DC while minimizing heat buildup in compact enclosures. Use Value: R_θJL = 10°C/W allows direct thermal coupling to chassis or PCB ground plane; 150°C T_JMAX supports ambient temps up to 85°C.	Use Scenario: Input rectification in 24V industrial DIN-rail power supplies with wide input range (e.g., 18–32V DC input). IC Role / Device Role / Timing Role: Provides reverse-polarity protection and input surge clamping in redundant power inputs. Use Value: 50V V_RRM provides 2× safety margin over 24V nominal; 5 µA I_R @ 25°C ensures negligible leakage in always-on monitoring circuits.

DC-DC Converter Output Rectification

Switching Mode Inverter Freewheeling

Use Scenario: Secondary-side synchronous or diode rectification in isolated 5–24V buck-derived DC-DC modules.

IC Role / Device Role / Timing Role: Unidirectional current valve providing low-loss output conduction and fast reverse blocking during transformer reset.

Use Value: 0.95V V_F minimizes power loss at 3A load; 35ns t_rr prevents cross-conduction in phase-shifted topologies.

Use Scenario: Freewheeling path across inductive loads (e.g., motor windings, solenoids) in H-bridge inverters.

IC Role / Device Role / Timing Role: Clamp-induced back-EMF spikes and recirculate stored inductive energy during PWM off-time.

Use Value: 125A I_FSM safely absorbs repetitive inductive kickback; DO-201AD mechanical robustness ensures long-term reliability under vibration.

AC-DC Adapter Secondary Rectification

Industrial 24V Power Supply Input Stage

Use Scenario: Output rectification in universal-input 5V/12V/24V AC-DC adapters with <100 kHz flyback operation.

IC Role / Device Role / Timing Role: Converts transformer secondary AC to regulated DC while minimizing heat buildup in compact enclosures.

Use Value: R_θJL = 10°C/W allows direct thermal coupling to chassis or PCB ground plane; 150°C T_JMAX supports ambient temps up to 85°C.

Use Scenario: Input rectification in 24V industrial DIN-rail power supplies with wide input range (e.g., 18–32V DC input).

IC Role / Device Role / Timing Role: Provides reverse-polarity protection and input surge clamping in redundant power inputs.

Use Value: 50V V_RRM provides 2× safety margin over 24V nominal; 5 µA I_R @ 25°C ensures negligible leakage in always-on monitoring circuits.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
STTH3L05S (STMicroelectronics)	V_RRM = 50V, I_F = 3A, t_rr = 30ns, V_F = 0.92V @ 3A, DO-201AD	Marginally faster t_rr and lower V_F; identical package and pinout	Preferred where sub-30ns recovery is critical; same PCB footprint and thermal profile.
ES3D (ON Semiconductor)	V_RRM = 200V, I_F = 3A, t_rr = 35ns, V_F = 0.92V @ 3A, DO-201AD	Higher V_RRM rating; otherwise electrically and mechanically equivalent	Select when future-proofing for 100–200V designs or shared BOM across multiple voltage grades.

Compared with STTH3L05S and ES3D, the SF31G-A offers identical 3A/50V/35ns performance in DO-201AD but with slightly higher V_F (0.95V), making it optimal for cost-sensitive 50V systems where 30ns speed is not required and 200V+ margin is unnecessary.

Availability

SF31G-A is available at Aetrix Electronics and suitable for DC-DC converter output rectification, switching mode inverter freewheeling, and industrial 24V power supply input stages requiring stable component supply and long-lifecycle support.

Supply support for SF31G-A 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving industrial, computing, and consumer markets since 1979.

The SF31G-A belongs to TSC's SFxG-A super fast rectifier family, engineered specifically for high-efficiency, high-reliability switching power conversion in space-constrained and thermally demanding environments.

FAQ

What is the maximum junction temperature rating for the SF31G-A?

The SF31G-A has a maximum junction temperature (T_JMAX) of +150°C, verified per absolute maximum ratings in the official TSC datasheet revision B2105. This rating allows reliable operation in industrial ambient conditions up to 85°C when mounted on adequately sized copper pours. Thermal derating begins above 25°C ambient, with full 3A current permitted only below 75°C case temperature.

Is the SF31G-A RoHS and halogen-free compliant?

Yes, the SF31G-A is RoHS compliant and halogen-free per IEC 61249-2-21, as confirmed in the "Features" section of the TSC SF31G-A–SF38G-A datasheet (Version B2105). The molding compound meets UL 94V-0 flammability standards, and the pure tin-plated leads satisfy J-STD-002 solderability requirements.

What is the reverse recovery time (t_rr) of the SF31G-A and under what test conditions?

The SF31G-A has a reverse recovery time (t_rr) of 35 ns, measured under conditions of I_F = 0.5 A, I_R = 1.0 A, and I_rr = 0.25 A, as specified in the Electrical Specifications table of the TSC datasheet. This value applies across the full operating temperature range and is validated using standardized double-pulse test methodology.

Does the SF31G-A have a specified junction-to-ambient thermal resistance (R_θJA)?

Yes, the SF31G-A specifies R_θJA = 35°C/W under standard JEDEC test conditions (still air, no heatsink), and R_θJL = 10°C/W (junction-to-lead) for board-level thermal design. The lower R_θJL value reflects its suitability for thermal coupling via PCB copper or metal-core substrates in high-power-density applications.

What packaging options are available for the SF31G-A?

The SF31G-A is supplied in DO-201AD package, available in two standard packing formats: 1,250 units per tape-and-reel (SF31G-A) and 500 units per ammo box (SF31G-A A0G), as documented in the Ordering Information section of the TSC datasheet. Both variants share identical electrical and thermal specifications.

SF31G-A Specifications

Product attributes: Attribute value

Manufacturer:: Taiwan Semiconductor Corporation

Series:: -

Package/Case:: DO-201AD, Axial

Packaging:: Tape & Reel (TR)

Product Status:: Active

Technology:: Standard

Voltage - DC Reverse (Vr) (Max):: 50 V

Current - Average Rectified (Io):: 3A

Voltage - Forward (Vf) (Max) @ If:: 950 mV @ 3 A

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

Reverse Recovery Time (trr):: 35 ns

Current - Reverse Leakage @ Vr:: 5 µA @ 50 V

Capacitance @ Vr, F:: 80pF @ 4V, 1MHz

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: DO-201AD

Operating Temperature - Junction:: -55°C ~ 150°C

SF31G-A FAQ

1.How can I place an order for SF31G-A through Aetrix?

Please submit a Request for Quotation (RFQ) for SF31G-A 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 SF31G-A reliable?

The price and inventory of SF31G-A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SF31G-A is usually 5 days.

3.What payment methods are accepted for SF31G-A?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SF31G-A transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SF31G-A?

SF31G-A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SF31G-A 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 SF31G-A?

For technical support, including SF31G-A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SF31G-A requirements.

6.How does Aetrix verify that SF31G-A is sourced from the original manufacturer or authorized distributors?

All SF31G-A 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 SF31G-A meets industry standards.

7.What is the process for return or replacement of SF31G-A?

All SF31G-A units undergo pre-shipment inspection (PSI). If there is an issue with SF31G-A, 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 SF31G-A part is unused and in its original packaging.

Return procedure for SF31G-A:

1.Submit a request within 90 days.

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

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