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Alpha & Omega Semiconductor Inc. SMDJ40A
- Part No.:
- SMDJ40A
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ40A.pdf
- Description:
- 1CH 40V UNIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:9,519
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Product details
Overview
SMDJ40A 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 40 V reverse stand-off voltage (VRWM), 44.4–49.1 V breakdown voltage (VBR) at 1 mA, 64.5 V maximum clamping voltage (VC) at 46.6 A peak pulse current, and 3000 W peak pulse power dissipation on a 10/1000 µs waveform - deployed in industrial motor drives to protect IGBT gate drivers from inductive switching transients.
For engineers reviewing the SMDJ40A datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 µs surges, thermal resistance (RθJL = 15 °C/W), unidirectional polarity with cathode band marking, DO-214AB package compatibility, and compliance with J-STD-020 MSL Level 1 reflow requirements.
Technical Context
The SMDJ40A operates as a silicon avalanche diode optimized for fast transient suppression, with sub-1 ps response time from 0 V to breakdown. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low temperature coefficient (0.1% × VBR per °C ΔT), enabling predictable clamping across -55°C to +150°C operating range.
Mounted on 8.0 mm × 8.0 mm copper pads per terminal, it delivers 3000 W peak pulse power with 0.01% duty cycle limitation and supports 300 A non-repetitive forward surge (8.3 ms half-sine). Its unidirectional configuration uses a cathode band for polarity identification and excludes bidirectional operation unless specified with 'CA' suffix.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 40.0 V - Maximum continuous reverse voltage before significant leakage; defines safe operating DC bias level. |
| VBR @ IT=1 mA | 44.4–49.1 V - Avalanche breakdown threshold; ensures reliable turn-on during overvoltage events. |
| VC @ IPPM | 64.5 V - Clamped voltage at 46.6 A peak pulse; limits downstream component stress during surge. |
| PPPM (10/1000 µs) | 3000 W - Peak surge energy handling capacity; enables robust protection against lightning-induced transients. |
| TJ max | +150 °C - Maximum junction temperature; supports operation in high-ambient industrial environments. |
| RθJL | 15 °C/W - Junction-to-lead thermal resistance; critical for PCB copper pad layout and thermal derating. |
| Polarity | Unidirectional - Cathode-band marked; prevents reverse-bias conduction except during controlled clamping. |
Pinout & Package
DO-214AB (SMC J-Bend) surface-mount package with molded plastic case, matte tin lead-free plating, and JEDEC-compliant mechanical dimensions. Cathode identified by color band on body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry during forward conduction | Connected to protected line side; carries surge current into device during clamping. |
| Cathode | Current exit during forward conduction; marked with band | Connected to ground or reference rail; establishes unidirectional clamping direction and polarity alignment. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps from 0 V to VBR - Enables suppression of nanosecond-scale ESD and switching transients before system damage occurs. |
| Glass passivated junction | Stable VBR tolerance (±5%) and low IR drift - Ensures long-term reliability and consistent clamping across temperature and lifetime. |
| Low profile DO-214AB package | Height ≤ 2.6 mm - Supports high-density PCB layouts in space-constrained industrial and automotive ECUs. |
| MSL Level 1 rating | Peak reflow temperature 260 °C - Allows single-pass lead-free assembly without moisture-related popcorning or delamination. |
| UL 94V-0 flammability | Self-extinguishing plastic housing - Meets safety standards for enclosed power electronics and industrial enclosures. |
Applications
| Industrial Motor Drives | Automotive Power Modules |
|---|---|
Use Scenario: Protection of IGBT gate driver circuits against inductive kickback during PWM switching in 400 V DC bus inverters. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between gate and emitter to limit voltage overshoot to ≤64.5 V during dV/dt transients. Use Value: Prevents gate oxide rupture in SiC/IGBT drivers by clamping within 1 ps, maintaining <10 ns total protection latency. | Use Scenario: Surge suppression on 12 V battery-fed control inputs in engine control units exposed to load dump (ISO 7637-2 Pulse 5a). IC Role / Device Role / Timing Role: Primary front-end protector on LIN/CAN power rails, absorbing up to 3000 W for 10/1000 µs pulses. Use Value: Withstands 300 A surge current (8.3 ms) and maintains VRWM stability across -40°C to +125°C ambient. |
| Telecom Power Feeds | Renewable Energy Inverters |
Use Scenario: DC input protection for PoE-powered remote radio units subjected to induced lightning surges on outdoor cabling. IC Role / Device Role / Timing Role: Standoff-rated TVS on 48 V DC feed line, coordinated with upstream GDT and downstream ceramic capacitors. Use Value: 40 V VRWM allows clean operation under nominal PoE voltage while clamping at 64.5 V to preserve 5 V logic supply integrity. | Use Scenario: DC-link overvoltage protection in solar string inverters where PV array transients exceed 1 kV. IC Role / Device Role / Timing Role: Secondary clamping device parallel to bulk MOVs, providing precise low-clamp-voltage backup for fast-rising transients. Use Value: 15 °C/W RθJL enables direct thermal coupling to heatsinked busbars, sustaining repeated 3000 W pulses without thermal runaway. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC40A (Littelfuse) | Same DO-214AB package, 40 V VRWM, but lower PPPM (1500 W) and higher VC (70 V @ 21.4 A) | Lower energy handling limits use to lower-tier surge immunity (IEC 61000-4-5 Level 3 vs. Level 4) | Select SMDJ40A when 3000 W pulse capability and 64.5 V clamping are required for industrial-grade surge compliance. |
| 1.5KE40A (ON Semiconductor) | Through-hole DO-201 package, identical electrical specs but incompatible mounting and thermal path (RθJA = 100 °C/W vs. 75 °C/W) | Requires PCB redesign; unsuitable for automated SMT lines or high-power density layouts | Choose SMDJ40A for surface-mount production, thermal efficiency, and space-constrained designs where DO-214AB footprint is mandated. |
Compared with SAC40A and 1.5KE40A, the SMDJ40A uniquely combines 3000 W surge rating, 64.5 V clamping, DO-214AB SMT compatibility, and 15 °C/W junction-to-lead thermal resistance - making it optimal for high-reliability, high-power-density industrial and automotive transient suppression where board space and thermal management are critical.
Availability
SMDJ40A is available at Aetrix Electronics and suitable for industrial motor drives, automotive power modules, and telecom power feeds requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMDJ40A 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 automotive markets.
The SMDJ series is engineered for high-energy transient suppression in surface-mount power systems, targeting applications demanding >1 kW surge capability, low clamping voltage, and MSL Level 1 manufacturability.
FAQ
What is the maximum clamping voltage of the SMDJ40A under standard test conditions?
The SMDJ40A has a maximum clamping voltage (VC) of 64.5 V when subjected to its rated peak pulse current of 46.6 A on a 10/1000 µs waveform. This value is measured at TJ = 25°C with the device mounted on 8.0 mm × 8.0 mm copper pads per terminal, and represents the upper limit of voltage seen by downstream circuitry during surge events - critical for ensuring logic-level components remain within safe operating voltage margins.
Does the SMDJ40A support bidirectional transient suppression?
No, the SMDJ40A is a unidirectional TVS diode, indicated by the 'A' suffix and cathode band marking. For bidirectional operation, the SMDJ40CA variant must be used. The SMDJ40A conducts only during reverse-biased overvoltage events and blocks forward current above ~1 V, making it suitable for DC line protection where polarity is fixed and reverse transients dominate.
What is the thermal resistance from junction to lead (RθJL) for the SMDJ40A, and why does it matter?
The SMDJ40A has a typical junction-to-lead thermal resistance (RθJL) of 15 °C/W. This parameter directly impacts how effectively heat generated during surge events transfers from the silicon die to the PCB copper pads. A low RθJL enables higher sustained pulse repetition rates and improves reliability in thermally demanding applications such as motor drive gate protection, where repeated switching transients occur.
Can the SMDJ40A be used in lead-free reflow processes?
Yes, the SMDJ40A meets J-STD-020 MSL Level 1 specifications and is qualified for lead-free reflow with a maximum peak temperature of 260 °C. Its matte tin lead-free plating and UL 94V-0 compliant molding compound ensure robust performance through standard SMT assembly, eliminating moisture sensitivity concerns and supporting single-pass reflow without popcorn cracking or interfacial delamination.
How does the SMDJ40A's breakdown voltage tolerance compare to similar TVS diodes?
The SMDJ40A exhibits a breakdown voltage (VBR) range of 44.4 V to 49.1 V at 1 mA test current - a ±5% tolerance around the nominal 46.75 V midpoint. This tight tolerance, enabled by glass passivation and process control, exceeds industry-standard ±10% for many competing TVS diodes and ensures predictable, repeatable clamping behavior across production lots and temperature ranges.
SMDJ40A 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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 46.6A
- 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
SMDJ40A FAQ
1.How can I place an order for SMDJ40A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ40A 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 SMDJ40A reliable?
The price and inventory of SMDJ40A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ40A is usually 5 days.
3.What payment methods are accepted for SMDJ40A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ40A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ40A?
SMDJ40A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ40A 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 SMDJ40A?
For technical support, including SMDJ40A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ40A requirements.
6.How does Aetrix verify that SMDJ40A is sourced from the original manufacturer or authorized distributors?
All SMDJ40A 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 SMDJ40A meets industry standards.
7.What is the process for return or replacement of SMDJ40A?
All SMDJ40A units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ40A, 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 SMDJ40A part is unused and in its original packaging.
Return procedure for SMDJ40A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ40A Tags
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