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Diodes Incorporated SDT3A40SAFS-13
- Part No.:
- SDT3A40SAFS-13
- Manufacturer:
- Diodes Incorporated
- Category:
- Single Diodes
- Package:
- DO-214AC, SMA Flat Leads
- Datasheet:
-
SDT3A40SAFS-13.pdf
- Description:
- DIODE SCHOTTKY 40V 3A SMA-FS
- Quantity:
- Payment:
- Shipping:
Inventory:4,331
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Product details
Overview
SDT3A40SAFS-13 from Diodes Incorporated is a 40 V, 3 A trench Schottky barrier rectifier in SMA-FS package, optimized for high-efficiency SMPS and DC-DC converters with low forward voltage (0.45 V @ 3 A) and low leakage current (300 µA @ 40 V, 25°C). It operates up to +150°C junction temperature and serves as freewheeling or reverse polarity protection diode in compact power supplies.
For engineers reviewing the SDT3A40SAFS-13 datasheet, SDT3A40SAFS-13 pinout, SDT3A40SAFS-13 application, or SDT3A40SAFS-13 equivalent, key selection criteria include forward voltage drop at rated current, thermal resistance (RθJA = 50°C/W), reverse leakage behavior across temperature, and RoHS-compliant lead-free plating compatibility with automated assembly.
Technical Context
This Schottky rectifier uses trench MOS structure to achieve lower VF and higher switching speed than planar Schottky devices, enabling reduced conduction loss in high-frequency switching topologies. Its soft recovery characteristic minimizes EMI generation during reverse recovery transitions.
The SMA-FS package features a cathode band polarity indicator, matte tin-plated terminals solderable per MIL-STD-202 Method 208, and UL 94V-0 molded plastic housing with moisture sensitivity level 1 - suitable for standard reflow profiles without baking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 40 V - Maximum repetitive reverse voltage before breakdown; sets upper limit for blocking capability in DC-DC input stage or output rectification. |
| IO | 3 A - Average forward current rating at 25°C ambient; derates to ~1.5 A at 100°C case temperature per Figure 4. |
| VF(MAX) | 0.45 V @ 3 A, 25°C - Low conduction loss enables >95% efficiency in 12 V–24 V output buck converters at full load. |
| IR(MAX) | 300 µA @ 40 V, 25°C - Low leakage preserves battery life in reverse polarity protection circuits and reduces standby power loss. |
| TJ Range | −65°C to +150°C - Enables operation in under-hood automotive modules or industrial power supplies without thermal derating penalties. |
| RθJA | 50°C/W - Thermal resistance on FR-4 board (1"×1", 2 oz Cu); determines required copper area for thermal management at 3 A continuous. |
Pinout & Package
The SDT3A40SAFS-13 is a two-terminal discrete diode in SMA-FS surface-mount package. Cathode is marked by a visible band on the body; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry point | Connected to higher potential node (e.g., switch node in buck converter, positive rail in reverse polarity protection). |
| Cathode | Forward current exit / reverse blocking terminal | Marked with band; tied to output/ground side; blocks reverse current flow when anode is negative relative to cathode. |
Key Features
| Feature | Design Value |
|---|---|
| Trench Schottky architecture | Reduces forward voltage drop vs. planar Schottky while maintaining fast switching and soft recovery behavior. |
| +150°C maximum junction temperature | Enables use in thermally constrained spaces such as sealed LED drivers or enclosed industrial PSUs without forced air cooling. |
| Lead-free, halogen- and antimony-free "Green" construction | Complies with RoHS 3 (2015/863/EU) and meets automotive PPAP-ready material traceability requirements. |
| SMA-FS mechanical outline | Standardized footprint compatible with existing SMA tooling; 0.033 g mass supports lightweight portable power designs. |
Applications
| SMPS Input Rectification | DC-DC Buck Converter Freewheeling |
|---|---|
Use Scenario: AC-DC adapter front-end rectification feeding a PFC stage or isolated flyback controller. IC Role / Device Role: Unidirectional current path with minimal conduction loss and low EMI during turn-off. Use Value: 0.45 V VF reduces heat generation versus silicon diodes, allowing smaller heatsinks in space-constrained adapters. | Use Scenario: Synchronous buck converter output stage where low VF improves light-load efficiency. IC Role / Device Role: Freewheeling path for inductor current during high-side FET off-time. Use Value: Soft switching limits voltage overshoot and radiated emissions, easing EMC compliance in Class B equipment. |
| Reverse Polarity Protection | Blocking Diode in Battery Backup Systems |
Use Scenario: 12 V automotive accessory module powered from vehicle battery with risk of accidental reverse connection. IC Role / Device Role: Series-blocking element that conducts only when polarity is correct. Use Value: 300 µA max IR at 25°C ensures <3.6 µW standby loss - critical for always-on telematics units. | Use Scenario: Dual-supply system where main DC source and backup Li-ion battery share common load. IC Role / Device Role: Isolates battery from main rail during normal operation; prevents backfeed during charging. Use Value: 40 V VRRM safely handles 36 V nominal battery systems with transient spikes up to ±40 V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Schottky rectifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SS34H (ON Semiconductor) | Same 40 V VRRM, 3 A IO, but VF = 0.52 V @ 3 A; RθJA = 60°C/W. | Higher conduction loss and thermal resistance reduce efficiency in high-density layouts. | Acceptable where cost is prioritized over thermal performance and leakage is not critical. |
| SB340 (Good-Ark) | VF = 0.55 V @ 3 A; IR = 500 µA @ 40 V, 25°C; no AEC-Q200 qualification path stated. | Higher leakage may compromise battery runtime in always-on systems; lacks automotive change control documentation. | Use only in non-automotive commercial-grade power supplies with relaxed reliability requirements. |
Compared with SS34H and SB340, SDT3A40SAFS-13 delivers lower forward voltage and leakage, tighter thermal resistance, and documented RoHS/Green compliance - making it preferred for high-efficiency, thermally constrained, or automotive-adjacent designs requiring traceable sourcing.
Availability
SDT3A40SAFS-13 is available at Aetrix Electronics and suitable for SMPS input rectification, DC-DC buck converter freewheeling, reverse polarity protection, and blocking diode applications requiring stable component supply and RoHS-compliant manufacturing.
Supply support for SDT3A40SAFS-13 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
Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-performance power management, signal integrity, and protection solutions.
The SDT3A40SAFS-13 belongs to Diodes' advanced trench Schottky rectifier product line, engineered specifically for high-frequency, high-efficiency power conversion in space- and thermally-constrained applications.
FAQ
What is the maximum allowable case temperature for continuous operation?
The SDT3A40SAFS-13 has a maximum junction temperature of +150°C. With RθJC = 30°C/W and typical PCB layout, case temperature must remain ≤125°C to maintain safe margin. Derating curves in Figure 4 show 3 A rated at 25°C case, dropping to ~1.8 A at 85°C and ~1.2 A at 125°C.
Is this diode suitable for automotive applications?
The SDT3A40SAFS-13 is not AEC-Q101 qualified out-of-box, but Diodes Incorporated offers automotive-grade variants with PPAP capability and IATF 16949 manufacturing. For automotive use, contact Diodes directly to request qualified versions or change-controlled releases meeting AEC-Q200 stress test requirements.
How does the SMA-FS package differ from standard SMA?
SMA-FS is a flattened, low-profile variant of SMA with reduced height (max 1.20 mm vs. SMA's 2.2 mm) and optimized pad layout (E = 3.30–3.70 mm, HE = 4.40–4.80 mm). It maintains identical electrical specs but improves thermal dissipation and board-level reliability in dense layouts.
Can SDT3A40SAFS-13 replace a 1N5822 in an existing design?
Yes - both are 3 A, 40 V Schottky rectifiers in DO-201AD (1N5822) and SMA-FS packages. However, SDT3A40SAFS-13 offers lower VF (0.45 V vs. 0.55 V), better thermal resistance, and RoHS/Green compliance. PCB footprint and solder profile must be updated to accommodate the smaller SMA-FS package.
SDT3A40SAFS-13 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Series:
- -
- Package/Case:
- DO-214AC, SMA Flat Leads
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Last Time Buy
- Technology:
- Schottky
- Voltage - DC Reverse (Vr) (Max):
- 40 V
- Current - Average Rectified (Io):
- 3A
- Voltage - Forward (Vf) (Max) @ If:
- 450 mV @ 3 A
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- -
- Current - Reverse Leakage @ Vr:
- 300 µA @ 40 V
- Capacitance @ Vr, F:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA-FS
- Operating Temperature - Junction:
- -65°C ~ 150°C
SDT3A40SAFS-13 FAQ
1.How can I place an order for SDT3A40SAFS-13 through Aetrix?
Please submit a Request for Quotation (RFQ) for SDT3A40SAFS-13 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 SDT3A40SAFS-13 reliable?
The price and inventory of SDT3A40SAFS-13 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SDT3A40SAFS-13 is usually 5 days.
3.What payment methods are accepted for SDT3A40SAFS-13?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SDT3A40SAFS-13 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SDT3A40SAFS-13?
SDT3A40SAFS-13 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SDT3A40SAFS-13 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 SDT3A40SAFS-13?
For technical support, including SDT3A40SAFS-13 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SDT3A40SAFS-13 requirements.
6.How does Aetrix verify that SDT3A40SAFS-13 is sourced from the original manufacturer or authorized distributors?
All SDT3A40SAFS-13 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 SDT3A40SAFS-13 meets industry standards.
7.What is the process for return or replacement of SDT3A40SAFS-13?
All SDT3A40SAFS-13 units undergo pre-shipment inspection (PSI). If there is an issue with SDT3A40SAFS-13, 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 SDT3A40SAFS-13 part is unused and in its original packaging.
Return procedure for SDT3A40SAFS-13:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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