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Taiwan Semiconductor Corporation SF21G-T
- Part No.:
- SF21G-T
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Diodes
- Package:
- DO-204AC, DO-15, Axial
- Datasheet:
-
SF21G-T.pdf
- Description:
- 35NS, 2A, 50V, SUPER FAST RECOVE
- Quantity:
- Payment:
- Shipping:
Inventory:6,409
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Product details
Overview
SF21G-T from Taiwan Semiconductor is a 2 A, 50 V super fast rectifier diode in DO-204AC (DO-15) package, featuring 0.95 V forward voltage at 2 A and 35 ns reverse recovery time, used for freewheeling and DC-DC converter output rectification.
For engineers reviewing the SF21G-T datasheet, SF21G-T pinout, SF21G-T application, or SF21G-T equivalent, key selection criteria include repetitive peak reverse voltage (50 V), surge current rating (50 A), thermal resistance (65 °C/W), and RoHS/halogen-free compliance for industrial power conversion designs.
Technical Context
This single-die silicon rectifier uses glass passivated junction technology to achieve low forward voltage drop and high efficiency. Its 35 ns trr enables operation in high-frequency switching topologies up to several hundred kHz.
The device supports continuous forward current of 2 A with derating above 25 °C ambient, and withstands non-repetitive surge currents up to 50 A (8.3 ms half-sine). Junction temperature range is –55 °C to +150 °C, with thermal resistance from junction-to-ambient at 65 °C/W.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 50 V - Maximum repetitive reverse blocking voltage; defines minimum input/output isolation margin in 24–48 V DC-DC stages |
| IF | 2 A - Continuous average forward current; sets maximum steady-state power delivery capability |
| IFSM | 50 A - Non-repetitive surge current; enables robustness against inrush and fault transients |
| VF @ 2 A | 0.95 V - Forward voltage drop at rated current; directly determines conduction loss (1.9 W at 2 A) |
| trr | 35 ns - Reverse recovery time; limits switching frequency ceiling and reduces switching loss in hard-switched converters |
| RθJA | 65 °C/W - Junction-to-ambient thermal resistance; dictates heatsinking requirement for 2 A operation at elevated ambient |
| CJ @ 4 V | 40 pF - Junction capacitance at 4 V reverse bias; influences EMI generation and snubber design in high-dV/dt circuits |
Pinout & Package
Package: DO-204AC (DO-15), axial leaded, glass-passivated, cathode indicated by band. Weight: 0.400 g. Leads are pure tin plated, solderable per J-STD-002, and meet JESD 201 Class 1A whisker test.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry point | Connected to lower-potential node (e.g., switch node in buck sync rectifier or transformer secondary center-tap) |
| Cathode | Forward current exit / reverse blocking terminal | Connected to output rail; polarity band identifies this terminal for correct PCB orientation and circuit protection |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Enables stable long-term reliability under humidity and thermal cycling without hermetic sealing |
| Low VF (0.95 V @ 2 A) | Reduces conduction loss by ~15% vs. standard fast rectifiers, improving efficiency in 12–48 V output stages |
| 35 ns trr | Supports switching frequencies >200 kHz with minimal reverse recovery loss, suitable for compact SMPS designs |
| RoHS & halogen-free | Meets IEC 61249-2-21; eliminates brominated flame retardants for safer end-of-life processing |
Applications
| DC-DC Converter Output Rectification | Switching Mode Inverter Freewheeling |
|---|---|
Use Scenario: Secondary-side rectification in isolated flyback or forward converters delivering 5–24 V at up to 2 A. IC Role / Device Role / Timing Role: Unidirectional current path enabling energy transfer from transformer to output capacitor; replaces slower diodes to reduce losses. Use Value: 0.95 V VF and 35 ns trr cut total rectifier loss by ≥25% vs. standard FR107, improving full-load efficiency by 0.8–1.2%. | Use Scenario: Freewheeling path across inductive loads (e.g., motor windings or relay coils) in H-bridge inverters. IC Role / Device Role / Timing Role: Provides low-loss return path during switch off-time, clamping inductive kickback and preventing voltage overshoot. Use Value: 50 A IFSM withstands repeated motor stall surges; 65 °C/W RθJA allows direct PCB mounting without heatsink in ≤10 W systems. |
| Industrial AC-DC Adapter Input Stage | LED Driver Constant-Current Loop Protection |
Use Scenario: Bridge rectifier input stage in universal-input (90–264 VAC) offline adapters rated ≤30 W. IC Role / Device Role / Timing Role: Converts AC line to pulsating DC; operates in discontinuous conduction mode with low duty cycle stress. Use Value: 50 V VRRM exceeds peak line voltage (375 V) only when used in voltage-doubler configurations; standard use requires ≥600 V parts - SF21G-T is not rated for this role. | Use Scenario: Reverse-polarity protection and overvoltage clamp in constant-current LED driver feedback loops. IC Role / Device Role / Timing Role: Blocks reverse current during LED string open-circuit faults and shunts transient overvoltage spikes. Use Value: 5 µA IR at 25 °C ensures negligible leakage in precision current sensing; 150 °C TJ max supports sealed fixture environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar super fast rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STTH2R06 | VRRM = 600 V, VF = 1.15 V @ 2 A, trr = 30 ns, DO-204AL (DO-41) package | Higher voltage rating suits universal-input AC-DC; slightly higher VF increases conduction loss | Select when >100 V reverse blocking is required; not drop-in due to different package outline and lead spacing |
| ON Semi MUR220 | VRRM = 200 V, VF = 0.93 V @ 2 A, trr = 35 ns, DO-204AC (DO-15) package | Same footprint and pinout; higher VRRM provides safety margin for 48 V bus transients | Direct physical replacement with identical mounting; verify system reverse voltage does not exceed 50 V before substituting SF21G-T |
Compared with STTH2R06 and MUR220, the SF21G-T offers lowest VF among 50 V-rated super fast rectifiers in DO-15, but requires strict adherence to its 50 V VRRM limit-making it optimal for fixed 24/36 V DC-DC outputs where size and conduction loss dominate.
Availability
SF21G-T is available at Aetrix Electronics and suitable for DC-DC converters, switching mode inverters, and freewheeling applications requiring stable component supply, consistent parametric performance, and RoHS-compliant manufacturing.
Supply support for SF21G-T 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 rectifiers, TVS diodes, and MOSFETs for industrial and computing markets.
The SF21G-T belongs to TSC's SF2xG-T super fast rectifier family, designed specifically for high-efficiency, high-frequency power conversion in space-constrained industrial and telecom power supplies.
FAQ
What is the maximum repetitive peak reverse voltage rating for SF21G-T?
The SF21G-T has a maximum repetitive peak reverse voltage (VRRM) rating of 50 V. This value is fixed and specific to the SF21G-T variant; other members of the SF2xG-T family have higher ratings (e.g., SF22G-T = 100 V). Exceeding 50 V in continuous reverse bias risks catastrophic failure. The SF21G-T must not be substituted in circuits where reverse voltage may exceed this limit, even momentarily.
What is the forward voltage drop of SF21G-T at its rated current?
The SF21G-T exhibits a typical forward voltage (VF) of 0.95 V at 2 A and 25 °C junction temperature. This value is measured under pulsed conditions (PW = 0.3 ms) and represents the dominant conduction loss contributor. At elevated temperatures or higher currents, VF decreases slightly due to negative temperature coefficient, but system-level thermal design must ensure junction temperature remains within –55 °C to +150 °C limits.
Does SF21G-T have a defined reverse recovery time, and how is it measured?
Yes, the SF21G-T has a maximum reverse recovery time (trr) of 35 ns. It is measured under standardized conditions: IF = 0.5 A, IR = 1.0 A, and Irr = 0.25 A, using the test circuit shown in Figure 6 of the official datasheet. This parameter confirms suitability for high-frequency switching applications up to ~300 kHz, where fast turn-off minimizes switching loss and EMI generation.
Is SF21G-T compliant with environmental regulations such as RoHS and halogen-free standards?
Yes, the SF21G-T is RoHS compliant and halogen-free per IEC 61249-2-21. The molding compound meets UL 94V-0 flammability rating, and the pure tin-plated leads satisfy J-STD-002 solderability requirements. These certifications are verified per TSC's C2105 revision documentation and apply specifically to the SF21G-T production lot configuration.
What is the thermal resistance from junction to ambient for SF21G-T, and how does it affect layout?
The SF21G-T has a junction-to-ambient thermal resistance (RθJA) of 65 °C/W under standard JEDEC test conditions (single device on 1-inch² FR-4 board, 2 oz copper). This means that at 2 A continuous current and 0.95 V VF, the resulting 1.9 W dissipation raises junction temperature by ~124 °C above ambient. To maintain TJ ≤ 150 °C, ambient must stay below 26 °C unless additional copper area or airflow is provided - guiding PCB copper pour and placement decisions.
SF21G-T Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Series:
- -
- Package/Case:
- DO-204AC, DO-15, Axial
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Standard
- Voltage - DC Reverse (Vr) (Max):
- 50 V
- Current - Average Rectified (Io):
- 2A
- Voltage - Forward (Vf) (Max) @ If:
- 950 mV @ 2 A
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- 35 ns
- Current - Reverse Leakage @ Vr:
- 5 µA @ 50 V
- Capacitance @ Vr, F:
- 40pF @ 4V, 1MHz
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- DO-204AC (DO-15)
- Operating Temperature - Junction:
- -55°C ~ 150°C
SF21G-T FAQ
1.How can I place an order for SF21G-T through Aetrix?
Please submit a Request for Quotation (RFQ) for SF21G-T 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 SF21G-T reliable?
The price and inventory of SF21G-T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SF21G-T is usually 5 days.
3.What payment methods are accepted for SF21G-T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SF21G-T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SF21G-T?
SF21G-T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SF21G-T 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 SF21G-T?
For technical support, including SF21G-T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SF21G-T requirements.
6.How does Aetrix verify that SF21G-T is sourced from the original manufacturer or authorized distributors?
All SF21G-T 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 SF21G-T meets industry standards.
7.What is the process for return or replacement of SF21G-T?
All SF21G-T units undergo pre-shipment inspection (PSI). If there is an issue with SF21G-T, 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 SF21G-T part is unused and in its original packaging.
Return procedure for SF21G-T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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