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Alpha & Omega Semiconductor Inc. SMDJ51A
- Part No.:
- SMDJ51A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ51A.pdf
- Description:
- 1CH 51V UNIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:4,974
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Product details
Overview
SMDJ51A from Alpha & Omega Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power lines and signal interfaces. It features a 51.0 V reverse stand-off voltage, 56.7–62.7 V breakdown voltage at 1 mA, 82.4 V maximum clamping voltage at 36.5 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives to safeguard IGBT gate drivers against inductive switching transients.
For engineers reviewing the SMDJ51A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC VDS rating, thermal resistance (RθJL = 15 °C/W), unidirectional polarity confirmation via cathode band marking, and DO-214AB package compatibility with 8.0 mm × 8.0 mm copper pad layouts.
Technical Context
The SMDJ51A operates as a silicon avalanche diode with glass-passivated junction, delivering sub-1 ps response time from 0 V to breakdown. Its unidirectional polarity requires cathode connection toward the protected circuit's positive rail, enabling precise overvoltage clamping without reverse conduction during normal operation.
Designed for non-repetitive surge events at ≤0.01% duty cycle, it sustains 300 A peak forward surge current (8.3 ms half-sine) and maintains stable breakdown voltage with ±0.1% / °C temperature coefficient. Thermal performance is validated under JEDEC DO-214AB mounting conditions: 8.0 mm × 8.0 mm copper pads per terminal.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 51.0 V - Maximum continuous reverse operating voltage before clamping begins; sets minimum system DC bus margin. |
| VBR @ IT=1 mA | 56.7–62.7 V - Verified avalanche onset range; ensures predictable turn-on within 11% tolerance. |
| Vc @ IPPM | 82.4 V - Clamped voltage at 36.5 A peak pulse; defines worst-case stress on downstream MOSFETs or controllers. |
| PPPM (10/1000 µs) | 3000 W - Peak surge energy handling capacity; supports IEC 61000-4-5 Level 4 (4 kV) compliance with proper layout. |
| RθJL | 15 °C/W - Junction-to-lead thermal resistance; enables direct solder-pad thermal path for sustained pulse recovery. |
| TJ max | +150 °C - Maximum junction temperature; allows operation in enclosed industrial enclosures up to 85 °C ambient with derating. |
| IR @ VRWM | 2.0 µA - Reverse leakage at rated stand-off; negligible power loss in 24/48 V DC systems. |
Pinout & Package
DO-214AB (SMC J-Bend) package: molded plastic case with matte tin lead-free plating, JEDEC-compliant outline, cathode indicated by color band on unidirectional variants. Mounting requires 8.0 mm × 8.0 mm copper pads per terminal per datasheet thermal test condition.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Ground-reference terminal | Connected to system ground or low-side return; completes clamping path during transient. |
| Cathode | Protected-rail terminal | Marked with color band; ties to +51 V DC line or IGBT gate driver supply rail to clamp overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures long-term reliability and stable VBR across temperature and humidity stress. |
| Low-profile DO-214AB package | Enables compact placement near ESD-prone connectors or power stage MOSFETs without height interference. |
| Built-in strain relief | Reduces mechanical stress on solder joints during board flex or thermal cycling in motor control modules. |
| MSL1 moisture sensitivity | Allows reflow at 260 °C peak without preconditioning; eliminates bake step in high-volume manufacturing. |
| UL 94V-0 flammability rating | Meets safety standards for enclosed industrial equipment where flame propagation must be suppressed. |
Applications
| Industrial Motor Drives | DC Power Supply Inputs |
|---|---|
Use Scenario: Protecting IGBT gate driver ICs from Miller-induced voltage spikes during high-dI/dt switching in 48 V servo inverters. IC Role / Device Role / Timing Role: Unidirectional TVS clamping device placed between gate driver output and IGBT gate, activated within <1 ps of overvoltage event. Use Value: Limits gate-source voltage to ≤82.4 V, preventing gate oxide rupture while maintaining driver timing integrity. | Use Scenario: Suppressing load-dump transients on 24 V automotive-grade DC-DC converter inputs in factory automation PLCs. IC Role / Device Role / Timing Role: Primary surge suppression element located at input connector, clamping 3000 W pulses per ISO 7637-2 Pulse 5a. Use Value: Absorbs 36.5 A peak current without degradation, preserving upstream fuse coordination and downstream regulator stability. |
| Telecom Power Feeds | Renewable Energy Controllers |
Use Scenario: Safeguarding PoE+ (IEEE 802.3at) powered device front-end rectifiers against lightning-induced surges on outdoor Ethernet runs. IC Role / Device Role / Timing Role: Secondary-level TVS on DC input rail after primary gas discharge tube, responding after nanosecond-scale front-end filtering. Use Value: Clamps residual transients to 82.4 V with 2.0 µA leakage, ensuring no standby power penalty on always-on network interfaces. | Use Scenario: Protecting MPPT controller MOSFETs from grid-switching transients in solar string combiner boxes exposed to rapid AC line reconnection. IC Role / Device Role / Timing Role: High-energy clamping device mounted directly at DC bus terminals, absorbing repetitive 10/1000 µs surges up to 0.01% duty cycle. Use Value: Maintains 150 °C max junction temperature under repeated 3000 W pulses, avoiding thermal runaway in unventilated enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC51A (Littelfuse) | Same DO-214AB package, identical 51 V VRWM and 82.4 V Vc, but higher IR (5 µA vs. 2 µA) and lower PPPM (2500 W). | Less suitable for ultra-low-leakage 24 V sensor power rails; acceptable for general-purpose 48 V power inputs. | Select SAC51A only if legacy Littelfuse sourcing is required and 500 W lower surge rating is acceptable. |
| 1.5KE51A (ON Semiconductor) | Through-hole DO-201 package, same electrical specs but RθJA = 100 °C/W (vs. 75 °C/W for SMDJ51A), requiring larger PCB area for thermal management. | Not viable for space-constrained SMT-only designs; limited to mixed-technology boards with through-hole capability. | Choose 1.5KE51A only when existing through-hole infrastructure prohibits SMT adoption or when higher mechanical robustness is prioritized over board density. |
Compared with SAC51A and 1.5KE51A, the SMDJ51A delivers superior thermal performance in surface-mount layouts (RθJL = 15 °C/W), tighter leakage (2 µA), and full 3000 W surge capacity - making it optimal for high-density industrial power electronics where footprint, thermal efficiency, and precision clamping are jointly critical.
Availability
SMDJ51A is available at Aetrix Electronics and suitable for industrial motor drives, DC power supply inputs, and renewable energy controllers requiring stable component supply with RoHS, halogen-free, and MSL1-compliant sourcing.
Supply support for SMDJ51A 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
Alpha & Omega Semiconductor (AOS) is a fabless power semiconductor company specializing in high-efficiency MOSFETs, TVS diodes, and power ICs for industrial, computing, and consumer markets.
The SMDJxxxA series was engineered specifically for high-power surface-mount surge protection in harsh environments - emphasizing low clamping voltage, repeatable avalanche behavior, and JEDEC-qualified thermal reliability in DO-214AB packaging.
FAQ
What is the maximum clamping voltage of the SMDJ51A under standard test conditions?
The SMDJ51A exhibits a maximum clamping voltage (VC) of 82.4 V when subjected to its rated peak pulse current of 36.5 A on a 10/1000 µs waveform. This value is measured at TA = 25 °C with 8.0 mm × 8.0 mm copper pads per terminal, and defines the upper voltage limit imposed on protected circuits during surge events. The SMDJ51A maintains this clamping performance consistently due to its glass-passivated avalanche junction.
Does the SMDJ51A support bidirectional transient suppression?
No, the SMDJ51A is a unidirectional TVS diode, indicated by the "A" suffix and cathode band marking. For bidirectional operation, the SMDJ51CA variant must be used - it provides symmetrical clamping in both polarities. The SMDJ51A conducts only during reverse-biased overvoltage events and blocks forward current beyond its 300 A surge rating, making it unsuitable for AC-coupled or dual-polarity signal lines without external circuitry.
What is the thermal resistance from junction to ambient for the SMDJ51A?
The SMDJ51A has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on 8.0 mm × 8.0 mm copper pads per terminal, per JEDEC DO-214AB standard test conditions. This value assumes no additional heatsinking and is used to calculate steady-state temperature rise under continuous power dissipation - though the device is intended for transient, not continuous, operation. Its lower RθJL of 15 °C/W highlights the importance of direct pad conduction for pulse recovery.
How does the SMDJ51A achieve its fast response time?
The SMDJ51A achieves a typical response time of less than 1.0 ps from 0 V to breakdown voltage due to its optimized silicon avalanche structure and minimal parasitic capacitance (<100 pF at 1 MHz). This speed is intrinsic to the diode's junction physics and requires no external triggering - enabling protection of sensitive gate drivers and communication interfaces before damaging voltage levels are reached. The SMDJ51A's sub-picosecond response is verified under standardized 10/1000 µs waveform testing.
Is the SMDJ51A compliant with lead-free and environmental regulations?
Yes, the SMDJ51A is a certified AOS Green Product: fully RoHS-compliant, halogen-free, and lead-free with matte tin plating. It meets UL 94V-0 flammability requirements and is rated MSL1 per J-STD-020, allowing peak reflow temperatures up to 260 °C without baking. These qualifications make the SMDJ51A suitable for global industrial and telecom deployments where regulatory compliance and long-term material sustainability are mandatory.
SMDJ51A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 36.5A
- Power - Peak Pulse:
- 3000W (3kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AB
SMDJ51A FAQ
1.How can I place an order for SMDJ51A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ51A 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 SMDJ51A reliable?
The price and inventory of SMDJ51A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ51A is usually 5 days.
3.What payment methods are accepted for SMDJ51A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ51A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ51A?
SMDJ51A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ51A 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 SMDJ51A?
For technical support, including SMDJ51A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ51A requirements.
6.How does Aetrix verify that SMDJ51A is sourced from the original manufacturer or authorized distributors?
All SMDJ51A 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 SMDJ51A meets industry standards.
7.What is the process for return or replacement of SMDJ51A?
All SMDJ51A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ51A, 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 SMDJ51A part is unused and in its original packaging.
Return procedure for SMDJ51A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ51A Tags
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