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Taiwan Semiconductor Corporation SS34ALH
- Part No.:
- SS34ALH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- Single Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SS34ALH.pdf
- Description:
- 3A, 40V, SCHOTTKY RECTIFIER
- Quantity:
- Payment:
- Shipping:
Inventory:2,057
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Product details
Overview
SS34ALH from Taiwan Semiconductor is a 3A, 40V Schottky barrier surface-mount rectifier in Thin SMA package, featuring low forward voltage (0.47 V at 3A/25°C), high surge capability (70 A IFSM), AEC-Q101 qualification, and 150°C maximum junction temperature. It serves as a primary output rectifier in compact DC/DC converters for automotive infotainment power supplies.
For engineers reviewing the SS34ALH datasheet, SS34ALH pinout, SS34ALH application, or SS34ALH equivalent, key selection criteria include forward voltage at rated current, thermal resistance (RθJL = 19°C/W), reverse leakage at 125°C (80 mA), and AEC-Q101 compliance for automotive-grade reliability validation.
Technical Context
The SS34ALH implements a single-die Schottky junction optimized for low conduction loss in high-frequency switching topologies. Its 40V VRRM, 3A continuous forward current rating, and 19°C/W junction-to-lead thermal resistance enable efficient operation in space-constrained, thermally demanding environments such as on-board DC/DC modules.
Designed for automated SMT placement, the device uses matte tin-plated leads compliant with J-STD-002 and meets JESD 201 Class 2 whisker resistance. Polarity is marked by a cathode band, and moisture sensitivity is rated Level 1 per J-STD-020 - eliminating bake requirements prior to reflow.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRRM | 40 V - Maximum repetitive reverse voltage before breakdown; sets safe operating limit in 12–24 V input DC/DC designs |
| IF | 3 A - Continuous forward current at TA = 25°C; defines steady-state power delivery capacity |
| IFSM | 70 A - Peak non-repetitive surge current (8.3 ms half-sine); supports cold-start and load-dump transient handling |
| VF | 0.47 V max at 3 A / 25°C - Low conduction loss directly reduces power dissipation and improves efficiency above 90% |
| RθJL | 19 °C/W - Junction-to-lead thermal resistance; enables direct heat transfer to PCB copper pad without heatsink |
| TJ max | 150 °C - Maximum junction temperature; allows operation in under-hood automotive environments |
| IR | 80 mA max at 40 V / 125°C - Reverse leakage determines standby power loss in always-on systems |
Pinout & Package
Package: Thin SMA - Surface-mount package with gull-wing leads, 0.028 g mass, UL 94V-0 molding compound, and cathode polarity indicated by band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point into Schottky junction | Connected to lower-potential node (e.g., switch node or ground return) in buck converter output stage |
| Cathode | Current exit point; marked by band | Connected to output rail; polarity marking ensures correct orientation during automated placement and visual inspection |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including temperature cycling, HTRB, and ESD testing - eliminates need for additional qualification effort |
| Low VF at high current | 0.47 V @ 3 A / 25°C reduces conduction loss by >30% vs. comparable 40 V silicon diodes, improving system efficiency |
| High IFSM | 70 A surge rating supports robustness against inrush and fault currents without derating in 12 V bus applications |
| Level 1 MSL | No floor life limitation or pre-reflow baking required - simplifies manufacturing logistics and reduces process cost |
| Thin SMA footprint | Compact 2.7 mm × 4.7 mm outline fits dense PCB layouts; compatible with standard SMA reflow profiles |
Applications
| Automotive Infotainment Power Supply | Industrial LED Driver Secondary Rectification |
|---|---|
Use Scenario: On-board 12 V to 5 V/3.3 V DC/DC converter supplying head unit MCU, display, and audio codecs. IC Role / Device Role / Timing Role: Output synchronous rectifier replacing MOSFET gate drive complexity with passive simplicity. Use Value: 0.47 V VF minimizes dropout and thermal rise in sealed enclosures, enabling 100% duty-cycle operation at full load. | Use Scenario: Secondary-side rectification in constant-current LED drivers for street lighting with 24 V input. IC Role / Device Role / Timing Role: Unidirectional current path converting transformer AC output to regulated DC for LED string bias. Use Value: 70 A IFSM withstands lamp strike transients; 150°C TJ rating sustains reliability in outdoor ambient up to 85°C. |
| USB-C PD Adapter Output Stage | Telecom PoE Midspan DC/DC Isolation |
Use Scenario: Final-stage rectification in 20–60 W USB-C power adapters with GaN-based primary-side switching. IC Role / Device Role / Timing Role: High-frequency freewheeling diode in active-clamp flyback or LLC secondary side. Use Value: 172 pF junction capacitance limits switching loss at 300–500 kHz; low VF maintains tight output regulation under dynamic load. | Use Scenario: Isolated 48 V to 12 V DC/DC conversion in PoE midspan injectors powering remote access points. IC Role / Device Role / Timing Role: Output rectifier in forward or push-pull topology delivering isolated low-voltage bias rails. Use Value: AEC-Q101 qualification provides extended lifetime assurance beyond typical telecom reliability requirements; RθJL = 19°C/W enables thermal coupling to internal chassis ground plane. |
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-3EYH04-M3/54 | Same 40 V VRRM, 3 A IF, but higher VF (0.55 V typ @ 3 A) and no AEC-Q101 qualification | Suitable for industrial/commercial SMPS where automotive qualification is not required | Select SS34ALH when AEC-Q101 compliance or lower conduction loss is mandatory |
| ON Semiconductor SB340-T | Identical 40 V/3 A rating and Thin SMA package, but VF = 0.52 V max @ 3 A and IFSM = 50 A (vs. 70 A) | Acceptable for general-purpose adapters but less robust in surge-prone automotive environments | Choose SS34ALH for higher surge margin and tighter VF control in thermally constrained designs |
Compared with VS-3EYH04-M3/54 and SB340-T, the SS34ALH delivers superior thermal performance (RθJL = 19°C/W), higher surge immunity (70 A), and automotive-grade qualification - making it the preferred choice for mission-critical 12 V rail rectification where efficiency, reliability, and qualification alignment are jointly prioritized.
Availability
SS34ALH is available at Aetrix Electronics and suitable for automotive infotainment power supplies, industrial LED drivers, and USB-C PD adapter designs requiring stable component supply, AEC-Q101 compliance, and consistent thermal performance across production batches.
Supply support for SS34ALH 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 semiconductor manufacturer specializing in discrete power devices, including Schottky rectifiers, TVS diodes, and MOSFETs, with global distribution and AEC-Q101-qualified product lines.
The SS34ALH belongs to TSC's ALH-series Schottky rectifier family, engineered specifically for high-efficiency, high-reliability DC/DC conversion in automotive and industrial applications where low forward voltage and robust surge handling are critical.
FAQ
What is the maximum junction temperature rating for the SS34ALH?
The SS34ALH has a maximum junction temperature (TJ) rating of +150°C, verified per absolute maximum ratings in the official Taiwan Semiconductor datasheet (Version B2103). This rating allows reliable operation in under-hood automotive environments and enclosed industrial enclosures. Derating curves confirm usable current capacity down to 1.5 A at 125°C ambient when mounted on a 5 mm × 5 mm Cu pad, ensuring design margin for SS34ALH in thermally aggressive applications.
Is the SS34ALH RoHS and halogen-free compliant?
Yes, the SS34ALH is RoHS compliant and halogen-free according to IEC 61249-2-21, as explicitly stated in the "Features" section of the Taiwan Semiconductor datasheet (Version B2103). The device uses matte tin-plated leads and UL 94V-0 molding compound, meeting both environmental and flammability requirements for modern electronics manufacturing and end-product certifications.
Does the SS34ALH have AEC-Q101 qualification?
Yes, the SS34ALH is explicitly AEC-Q101 qualified, as confirmed in the "FEATURES" section of the official Taiwan Semiconductor datasheet (Version B2103). This qualification covers stress tests including temperature cycling, high-temperature reverse bias (HTRB), and electrostatic discharge (ESD), validating its suitability for automotive power electronics without requiring additional customer-level qualification.
What is the forward voltage of the SS34ALH at 3 A and 125°C?
The SS34ALH exhibits a forward voltage of 0.41 V (typical) and 0.53 V (maximum) at 3 A and 125°C junction temperature, per the "ELECTRICAL SPECIFICATIONS" table in the Taiwan Semiconductor datasheet (Version B2103). This low, temperature-stable VF ensures minimal conduction loss and predictable thermal behavior in high-ambient automotive or industrial applications using SS34ALH.
What packaging format is available for the SS34ALH?
The SS34ALH is supplied in Tape & Reel packaging, with 14,000 units per reel, as specified in the "ORDERING INFORMATION" section of the Taiwan Semiconductor datasheet (Version B2103). The Thin SMA package is compatible with standard SMT pick-and-place equipment and reflow profiles, supporting high-yield automated assembly for SS34ALH in volume production.
SS34ALH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Series:
- -
- Package/Case:
- DO-221AC, SMA Flat Leads
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Technology:
- Schottky
- Voltage - DC Reverse (Vr) (Max):
- 40 V
- Current - Average Rectified (Io):
- 3A
- Voltage - Forward (Vf) (Max) @ If:
- 590 mV @ 3 A
- Speed:
- Fast Recovery =< 500ns, > 200mA (Io)
- Reverse Recovery Time (trr):
- -
- Current - Reverse Leakage @ Vr:
- 200 µA @ 40 V
- Capacitance @ Vr, F:
- 54pF @ 4V, 1MHz
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- Thin SMA
- Operating Temperature - Junction:
- -55°C ~ 150°C
SS34ALH FAQ
1.How can I place an order for SS34ALH through Aetrix?
Please submit a Request for Quotation (RFQ) for SS34ALH 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 SS34ALH reliable?
The price and inventory of SS34ALH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SS34ALH is usually 5 days.
3.What payment methods are accepted for SS34ALH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SS34ALH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SS34ALH?
SS34ALH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SS34ALH 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 SS34ALH?
For technical support, including SS34ALH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SS34ALH requirements.
6.How does Aetrix verify that SS34ALH is sourced from the original manufacturer or authorized distributors?
All SS34ALH 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 SS34ALH meets industry standards.
7.What is the process for return or replacement of SS34ALH?
All SS34ALH units undergo pre-shipment inspection (PSI). If there is an issue with SS34ALH, 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 SS34ALH part is unused and in its original packaging.
Return procedure for SS34ALH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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