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Taiwan Semiconductor Corporation SRAF840
- Part No.:
- SRAF840
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Diodes
- Package:
- TO-220-2 Full Pack
- Datasheet:
-
SRAF840.pdf
- Description:
- 8A, 40V, PLANAR SCHOTTKY
- Quantity:
- Payment:
- Shipping:
Inventory:6,587
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Product details
Overview
SRAF840 from Taiwan Semiconductor is an AEC-Q101-qualified 8A, 40V Schottky barrier rectifier in ITO-220AC package, featuring low forward voltage (0.55 V at 8A, 25°C), high surge capability (150 A), and junction-to-case thermal resistance of 5°C/W - deployed in automotive-grade DC-DC converters and industrial SMPS.
For engineers reviewing the SRAF840 datasheet, SRAF840 pinout, SRAF840 application, or SRAF840 equivalent, key selection criteria include repetitive peak reverse voltage (40 V), reverse leakage (500 µA at 25°C), operating junction temperature range (–55°C to +125°C), and UL recognition (E-326243).
Technical Context
The SRAF840 uses a single-die Schottky structure optimized for low conduction loss and fast switching, with guard ring protection enabling robust over-voltage tolerance. Its 40 V VRRM and 10,000 V/µs dv/dt rating support stable operation in high-frequency switching topologies.
Thermally, it delivers 5°C/W junction-to-case resistance and supports continuous 8 A forward current up to 125°C junction temperature, with 150 A non-repetitive surge rating per 8.3 ms half-sine wave - critical for transient load handling in power adapters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 40 V - maximum repetitive reverse blocking voltage; defines safe operating limit in DC-DC output rectification |
| IF | 8 A - continuous average forward current; determines heatsink sizing in 25°C ambient designs |
| VF | 0.55 V @ 8 A, 25°C - low conduction loss enables >92% efficiency in 12 V output SMPS |
| IR | 500 µA @ 40 V, 25°C - low leakage preserves standby power in always-on systems |
| IFSM | 150 A @ 8.3 ms - withstands inrush surges during cold-start in automotive infotainment supplies |
| RθJC | 5°C/W - enables direct mounting to chassis for passive thermal management without forced air |
| TJ max | 125°C - rated for under-hood automotive environments per AEC-Q101 stress testing |
Pinout & Package
Package: ITO-220AC - insulated TO-220 variant with isolated tab, UL 94V-0 molding compound, matte tin-plated leads, and 0.56 N·m maximum mounting torque.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input current entry point | Connected to switching node (e.g., MOSFET drain) in synchronous buck rectification |
| Cathode | Output current exit point | Feeds filtered output rail; electrically tied to PCB ground plane via thermal pad |
| Tab (isolated) | Thermal path / mechanical anchor | Electrically isolated but thermally conductive; mounts directly to heatsink without insulator |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive power modules requiring reliability across –40°C to +125°C ambient |
| Guard ring over-voltage protection | Prevents premature avalanche breakdown under line transients up to 10,000 V/µs dv/dt |
| UL Recognized (E-326243) | Meets safety requirements for end-equipment certification in Class 2 power supplies |
| Halogen-free (IEC 61249-2-21) | Complies with RoHS and WEEE; eliminates corrosive halogen emissions during PCB reflow |
| 150 A surge rating | Survives 100+ cold-start cycles in 12 V automotive DC-DC converters without degradation |
Applications
| Automotive Infotainment Power Supply | Industrial AC-DC Adapter |
|---|---|
Use Scenario: 12 V input, 5 V/3 A output DC-DC converter powering head unit MCU and display backlight. IC Role / Device Role / Timing Role: Output rectifier in synchronous buck topology, conducting during low-side switch off-time. Use Value: 0.55 V VF reduces conduction loss by 35% vs. standard PN diodes, lowering thermal load on compact metal-core PCB. | Use Scenario: Universal-input (90–264 VAC) offline adapter delivering 19 V/4.74 A for industrial tablet charging. IC Role / Device Role / Timing Role: Secondary-side freewheeling diode in flyback converter, clamping transformer reset energy. Use Value: 40 V VRRM and 500 µA IR ensure low standby power (<150 mW) and reliable hold-up during brownouts. |
| Telecom Base Station PSU | LED Driver Secondary Rectification |
Use Scenario: 48 V intermediate bus converter supplying 3.3 V/20 A to FPGA and memory subsystems. IC Role / Device Role / Timing Role: Synchronous rectifier replacement in multiphase buck stages, operating at 300 kHz. Use Value: 10,000 V/µs dv/dt rating prevents false turn-on during fast gate-drive edge transitions. | Use Scenario: Constant-current LED driver with 24 V DC input powering 12 V, 2 A string in smart lighting fixture. IC Role / Device Role / Timing Role: Output rectifier in isolated forward converter, handling continuous 8 A peak current. Use Value: 5°C/W RθJC allows direct tab mounting to aluminum housing, eliminating discrete heatsink and saving 12 mm² board area. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Schottky rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Vishay VS-8EWH04FN-M3 | Same ITO-220AC package, 40 V VRRM, but higher VF (0.62 V @ 8 A) and lower IFSM (120 A) | Limited surge margin in automotive cold-crank scenarios | Acceptable where thermal budget permits higher conduction loss |
| ON Semiconductor MUR840EG | Ultrafast PN rectifier (not Schottky), 400 V VRRM, 1.7 V VF, 150 A IFSM | Higher switching loss; used only when reverse voltage margin >100 V required | Select only if system requires >100 V reverse standoff; not drop-in for SRAF840 |
Compared with VS-8EWH04FN-M3 and MUR840EG, the SRAF840 delivers superior efficiency in 12–24 V systems due to its 0.55 V forward drop and AEC-Q101 qualification - making it optimal for automotive and thermally constrained industrial converters where low VF and reliability are prioritized over ultra-high VRRM.
Availability
SRAF840 is available at Aetrix Electronics and suitable for automotive infotainment power supplies, industrial AC-DC adapters, and telecom base station PSUs requiring stable component supply with AEC-Q101 compliance and UL recognition.
Supply support for SRAF840 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 power semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving automotive, industrial, and consumer markets since 1979.
The SRAF8xx series belongs to TSC's AEC-Q101-qualified Schottky rectifier product line, engineered specifically for high-efficiency, high-reliability secondary-side rectification in automotive and industrial power conversion systems.
FAQ
What is the maximum junction temperature rating for the SRAF840?
The SRAF840 has a maximum junction temperature (TJ) rating of +125°C under continuous operation, validated per AEC-Q101 stress testing. This allows deployment in under-hood automotive environments and enclosed industrial enclosures without active cooling. The SRAF840 must be derated above 25°C ambient per the forward current derating curve in the official datasheet.
Is the SRAF840 pin-compatible with other parts in the SRAF8xx family?
Yes - all SRAF8xx devices, including the SRAF840, share identical ITO-220AC packaging, pinout (anode, cathode, isolated tab), and mechanical footprint. Voltage variants (SRAF820 to SRAF8150) differ only in VRRM and associated electrical parameters; no PCB layout change is needed when upgrading within the family.
Does the SRAF840 require a thermal pad or insulator when mounted to a heatsink?
No - the SRAF840 uses an ITO-220AC package with an electrically isolated tab, allowing direct mounting to a grounded heatsink without thermal pads or insulators. Its 5°C/W RθJC is specified under this condition, and mounting torque must not exceed 0.56 N·m to avoid die damage.
What is the reverse leakage current specification for the SRAF840 at elevated temperature?
At 100°C junction temperature and rated 40 V reverse voltage, the SRAF840 exhibits ≤15 mA reverse leakage current. This value is critical for standby power design in always-on systems; at 25°C, leakage is ≤500 µA, ensuring low quiescent loss in battery-backed applications.
How does the guard ring feature improve reliability of the SRAF840 in real-world applications?
The guard ring in the SRAF840 mitigates edge breakdown under high dv/dt transients (up to 10,000 V/µs), preventing localized hot spots and premature failure during switching node ringing. In automotive DC-DC converters, this extends lifetime under repeated load dump and ISO 7637-2 pulse conditions - a key factor in AEC-Q101 qualification.
SRAF840 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Series:
- -
- Package/Case:
- TO-220-2 Full Pack
- Packaging:
- Tube
- Product Status:
- Active
- Technology:
- Schottky
- Voltage - DC Reverse (Vr) (Max):
- 40 V
- Current - Average Rectified (Io):
- 8A
- Voltage - Forward (Vf) (Max) @ If:
- 550 mV @ 8 A
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- -
- Current - Reverse Leakage @ Vr:
- 500 µA @ 40 V
- Capacitance @ Vr, F:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- ITO-220AC
- Operating Temperature - Junction:
- -55°C ~ 125°C
SRAF840 FAQ
1.How can I place an order for SRAF840 through Aetrix?
Please submit a Request for Quotation (RFQ) for SRAF840 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 SRAF840 reliable?
The price and inventory of SRAF840 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SRAF840 is usually 5 days.
3.What payment methods are accepted for SRAF840?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SRAF840 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SRAF840?
SRAF840 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SRAF840 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 SRAF840?
For technical support, including SRAF840 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SRAF840 requirements.
6.How does Aetrix verify that SRAF840 is sourced from the original manufacturer or authorized distributors?
All SRAF840 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 SRAF840 meets industry standards.
7.What is the process for return or replacement of SRAF840?
All SRAF840 units undergo pre-shipment inspection (PSI). If there is an issue with SRAF840, 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 SRAF840 part is unused and in its original packaging.
Return procedure for SRAF840:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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