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Taiwan Semiconductor Corporation SF31G
- Part No.:
- SF31G
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Diodes
- Package:
- DO-201AD, Axial
- Datasheet:
-
SF31G.pdf
- Description:
- DIODE GEN PURP 50V 3A DO201AD
- Quantity:
- Payment:
- Shipping:
Inventory:4,504
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Product details
Overview
SF31G from Taiwan Semiconductor is a 3A, 50V super fast recovery rectifier diode in DO-201AD package, featuring 35ns reverse recovery time, 0.95V forward voltage at 3A/25°C, and 125A surge capability-designed for high-efficiency DC-DC converters and freewheeling paths in automotive-grade power supplies.
For engineers reviewing the SF31G datasheet, SF31G pinout, SF31G application, or SF31G equivalent, key selection criteria include VRRM = 50V, IF = 3A, trr = 35ns, RθJL = 10°C/W, and AEC-Q101 qualification status (SF31GH variant only).
Technical Context
The SF31G employs a single-die silicon PN junction optimized for fast switching with low conduction loss. Its 35ns reverse recovery time enables operation in high-frequency SMPS topologies up to several hundred kHz without excessive switching loss or EMI generation.
Thermally, it delivers RθJL = 10°C/W and RθJC = 9°C/W in DO-201AD, supporting continuous 3A conduction at TJ ≤ 150°C when mounted on ≥1 cm² copper area-critical for compact industrial and automotive power modules.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 50 V - Maximum repetitive reverse blocking voltage; sets minimum input/output isolation margin in 24V–48V bus applications |
| IF | 3 A - Continuous average forward current; supports 36W output at 12V with <1.0V drop in buck converter freewheel path |
| trr | 35 ns - Measured at IF=0.5A, IR=1.0A, Irr=0.25A; enables >300kHz switching without tail current losses |
| VF | 0.95 V @ 3A, 25°C - Low conduction loss reduces thermal stress in high-duty-cycle DC-DC stages |
| IFSM | 125 A - Non-repetitive surge rating for 8.3ms half-sine; withstands inrush and fault transients in 48V systems |
| RθJL | 10 °C/W - Junction-to-lead thermal resistance; allows direct PCB trace heat sinking without heatsink in ≤2W dissipation designs |
| CJ | 80 pF @ 1MHz, 4V - Low junction capacitance minimizes capacitive coupling noise in high-dv/dt gate drive circuits |
Pinout & Package
DO-201AD axial-leaded package with cathode band marking; leads are pure tin plated, solderable per J-STD-002, and meet JESD 201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Forward current entry point | Connected to switch node or transformer secondary in flyback/freewheel configurations |
| Cathode (banded end) | Forward current exit / reverse blocking terminal | Connected to output rail or ground return; polarity must match layout to prevent catastrophic failure |
Key Features
| Feature | Design Value |
|---|---|
| Super fast recovery (trr = 35ns) | Reduces switching loss and EMI in >200kHz SMPS, enabling smaller output filters and higher power density |
| Low VF (0.95V @ 3A) | Lowers conduction loss by ~15% vs. standard FR diodes, improving efficiency in 12–48V intermediate bus converters |
| High IFSM (125A) | Survives cold-start surges and short-circuit events in automotive 12V/24V systems without derating |
| AEC-Q101 qualified option (SF31GH) | Validated for automotive under-hood temperature cycling, vibration, and humidity exposure per stress test requirements |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally regulated industrial and transport electronics |
Applications
| DC-DC Converter Output Stage | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Secondary-side rectification in isolated 12V-to-5V/3.3V buck-derived converters powering microcontrollers and sensors. IC Role / Device Role / Timing Role: Freewheeling diode providing low-loss current path during high-side MOSFET off-time. Use Value: 0.95V VF and 35ns trr reduce total loss by ≥0.4W vs. standard FR107, lowering thermal load on compact PCBs. | Use Scenario: Reverse-polarity protection and load dump clamping in 12V BCM power inputs exposed to ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Clamp diode absorbing transient energy during battery disconnect or alternator load dump. Use Value: 125A IFSM and 50V VRRM safely clamp 100A/50V spikes without degradation over 100k cycles. |
| Industrial Motor Drive Snubber | LED Driver Freewheel Path |
Use Scenario: Snubber network in 24V/48V BLDC motor gate driver ICs to suppress inductive kickback from H-bridge shoot-through faults. IC Role / Device Role / Timing Role: Fast-clamping diode limiting voltage overshoot across MOSFETs during rapid current interruption. Use Value: 35ns trr ensures clamping activation within 50ns of dv/dt onset, preventing MOSFET avalanche breakdown. | Use Scenario: Freewheel path in constant-current LED drivers using buck topology with 36V input and 24V LED string output. IC Role / Device Role / Timing Role: Sustains LED current during PWM off-phase while minimizing forward conduction loss. Use Value: 0.95V VF limits power loss to 2.85W at 3A, reducing thermal stress on thermally constrained LED module PCBs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar super fast rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STTH3L06S | VRRM = 60V, trr = 30ns, VF = 0.92V @ 3A - slightly faster but higher cost | Same DO-201AD footprint; preferred where <30ns trr required for >500kHz operation | Select STTH3L06S if system operates above 400kHz or requires tighter trr tolerance |
| ON Semi MUR305 | VRRM = 50V, trr = 50ns, VF = 0.97V @ 3A - slower recovery, lower cost | Compatible pinout; used where EMI constraints allow longer trr and cost sensitivity dominates | Choose MUR305 for cost-sensitive 100–200kHz industrial supplies with relaxed EMI targets |
Compared with STTH3L06S and MUR305, the SF31G delivers optimal balance of 35ns trr, 0.95V VF, and AEC-Q101 availability (as SF31GH), making it ideal for mid-frequency automotive and industrial SMPS where reliability and efficiency are jointly prioritized.
Availability
SF31G is available at Aetrix Electronics and suitable for DC-DC converters, automotive body control modules, and industrial motor drive snubbers requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SF31G 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, specializing in power devices, rectifiers, and protection components since 1979.
The SF31G belongs to TSC's SF-series super fast rectifier family, engineered specifically for high-frequency switching power supplies in automotive, industrial, and telecom infrastructure where low VF, fast trr, and robust surge handling are mandatory.
FAQ
What is the maximum junction temperature rating for SF31G?
The SF31G has a maximum junction temperature (TJ) rating of +150°C, verified per absolute maximum ratings table in the official TSC datasheet revision H2105. This allows continuous operation at full 3A current in ambient temperatures up to +85°C when mounted on ≥1 cm² copper area, provided RθJA remains ≤35°C/W. The SF31G must not exceed this limit to maintain reliability and avoid parametric shift.
Is SF31G AEC-Q101 qualified?
The base SF31G part is not AEC-Q101 qualified; however, the SF31GH variant-identical in electrical and thermal specs-is fully AEC-Q101 qualified per version H2105 documentation. Customers requiring automotive qualification must specify SF31GH, which carries the same DO-201AD package and marking code plus "H" suffix denoting qualification status.
What is the reverse recovery time (trr) test condition for SF31G?
The SF31G reverse recovery time of 35ns is measured under standardized conditions: IF = 0.5A, IR = 1.0A, Irr = 0.25A, with specified pulse waveform per JEDEC JESD24-10. This value is guaranteed maximum and applies across the full operating temperature range of –55°C to +150°C, as confirmed in the Electrical Specifications section of the SF31G datasheet.
Can SF31G replace SF32G in a 100V circuit?
No-SF31G has VRRM = 50V and is not rated for 100V circuits. Using SF31G in place of SF32G (100V) risks catastrophic reverse breakdown during voltage transients or ripple peaks. The "x" digit in SF3xG explicitly defines VRRM: SF31G = 50V, SF32G = 100V. Substitution requires matching VRRM rating with ≥20% safety margin for reliable operation.
What is the lead finish and solderability specification for SF31G?
SF31G features pure tin-plated leads compliant with J-STD-002 for solderability, and passes JESD 201 Class 2 whisker testing. The device is compatible with standard reflow profiles (peak ≤260°C) and wave soldering. Lead finish meets RoHS and halogen-free requirements per IEC 61249-2-21, ensuring long-term intermetallic stability and corrosion resistance in humid environments.
SF31G 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 FAQ
1.How can I place an order for SF31G through Aetrix?
Please submit a Request for Quotation (RFQ) for SF31G 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 reliable?
The price and inventory of SF31G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SF31G is usually 5 days.
3.What payment methods are accepted for SF31G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SF31G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SF31G?
SF31G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SF31G 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?
For technical support, including SF31G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SF31G requirements.
6.How does Aetrix verify that SF31G is sourced from the original manufacturer or authorized distributors?
All SF31G 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 meets industry standards.
7.What is the process for return or replacement of SF31G?
All SF31G units undergo pre-shipment inspection (PSI). If there is an issue with SF31G, 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 part is unused and in its original packaging.
Return procedure for SF31G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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