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Alpha & Omega Semiconductor Inc. SMDJ78CA
- Part No.:
- SMDJ78CA
- Manufacturer:
- Alpha & Omega Semiconductor Inc.
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMDJ78CA.pdf
- Description:
- 1CH 78V BIDIRECTIONAL 3000W SMD
- Quantity:
- Payment:
- Shipping:
Inventory:2,706
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Product details
Overview
SMDJ78CA from Alpha & Omega Semiconductor is a bi-directional transient voltage suppressor (TVS) diode in DO-214AB (SMC J-Bend) package, designed for high-energy surge protection in DC power lines and data interfaces. It features 78 V reverse standoff voltage (VRWM), 86.7–95.8 V breakdown voltage (VBR @ 1 mA), 126 V maximum clamping voltage (VC @ 23.9 A), and 3000 W peak pulse power (10/1000 µs waveform).
For engineers reviewing the SMDJ78CA datasheet, pinout, applications, or equivalent options, key selection criteria include bidirectional clamping capability, low clamping ratio (VC/VRWM ≈ 1.61), JEDEC-compliant DO-214AB thermal performance (RθJA = 75 °C/W), and suitability for industrial power supply input stages, automotive body electronics, and PoE-powered equipment.
Technical Context
The SMDJ78CA operates as a bi-directional avalanche diode, providing symmetrical clamping in both polarities without external polarity constraints. Its glass-passivated junction ensures stable VBR tolerance (±5% typical), while the low-profile DO-214AB package enables surface-mount integration with built-in strain relief and matte tin lead-free plating compliant with RoHS and J-STD-020 MSL Level 1.
It delivers fast response (<1.0 ps from 0 V to VBR) and handles non-repetitive 8.3 ms half-sine surges up to 300 A (IFSM). Thermal design is supported by RθJL = 15 °C/W (junction-to-lead) and operation across –55 °C to +150 °C junction temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 78.0 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR @ IT=1 mA | 86.7–95.8 V - Confirmed breakdown threshold defining TVS turn-on precision |
| VC @ IPPM=23.9 A | 126.0 V - Clamped voltage during 3000 W surge, limiting downstream stress |
| PPPM (10/1000 µs) | 3000 W - Peak surge energy handling capacity under standard lightning waveform |
| TJ max | +150 °C - Maximum junction temperature enabling use in high-ambient industrial environments |
| Polarity | Bi-directional - Symmetric clamping for AC-coupled or floating signal/power lines |
| Package | DO-214AB (SMC J-Bend) - Standardized surface-mount outline with 8.0 mm × 8.0 mm copper pad thermal requirement |
Pinout & Package
DO-214AB (SMC J-Bend) package: molded plastic case with J-bend leads; cathode band denotes polarity for unidirectional variants, but SMDJ78CA is bi-directional and has no functional polarity marking-both terminals are electrically symmetric.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (bi-directional) | Surge current path | Both terminals serve identical clamping roles; no fixed anode/cathode designation-connected across protected line and return |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures long-term VBR stability and low leakage (<2 µA at VRWM) over temperature and lifetime |
| Fast response time <1.0 ps | Enables effective suppression of ESD and fast-rising transients before sensitive ICs are damaged |
| MSL Level 1 rating | Supports lead-free reflow up to 260 °C peak without moisture-induced failure |
| UL 94V-0 flammability | Meets safety standards for enclosure-integrated surge protection in certified end equipment |
| Built-in strain relief | Reduces mechanical stress on solder joints during board flex or thermal cycling |
Applications
| Industrial Power Input Protection | Automotive Body Control Module |
|---|---|
Use Scenario: 24 V DC power rail in programmable logic controllers exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary surge clamp placed upstream of DC-DC converters and microcontrollers. Use Value: Limits transient voltage to ≤126 V during 3000 W surges, preventing damage to 36 V-rated input stages. | Use Scenario: CAN bus power and I/O lines in door module ECUs subjected to battery reversal and jump-start transients. IC Role / Device Role / Timing Role: Bi-directional TVS protecting dual-rail (VCC and GND-referenced) signal paths. Use Value: Symmetric clamping maintains signal integrity during ±126 V transients without polarity dependency. |
| PoE-Powered Equipment | Telecom Line Interface |
Use Scenario: 48 V power pair in IEEE 802.3af/at PD devices encountering Ethernet cable surge events. IC Role / Device Role / Timing Role: Secondary surge protection stage after primary gas discharge tube (GDT). Use Value: Low clamping ratio (1.61×VRWM) ensures compliance with PoE Class 4–5 voltage limits during surge decay. | Use Scenario: T1/E1 interface cards in central office equipment facing lightning-induced common-mode surges. IC Role / Device Role / Timing Role: Differential-mode clamp across transformer secondary windings. Use Value: 3000 W rating sustains multiple 10/1000 µs surges per IEC 61000-4-5 Level 4 testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC78CA (Littelfuse) | Same VRWM (78 V), slightly higher VC (128 V), lower PPPM (2500 W) | Marginally reduced surge energy handling; suitable where 500 W headroom is acceptable | Select when sourcing diversification is required and 2500 W peak power meets system test margin |
| SMCJ78CA (ON Semiconductor) | Identical VRWM (78 V), same DO-214AB package, VC = 126 V, PPPM = 3000 W | Pin-to-pin compatible with identical thermal and electrical specs per datasheet Rev. 10 | Drop-in replacement with validated second-source availability and identical layout requirements |
Compared with SAC78CA and SMCJ78CA, the SMDJ78CA offers identical clamping performance and surge rating to SMCJ78CA-enabling seamless PCB reuse-while delivering 20% higher peak power than SAC78CA for systems requiring stricter IEC 61000-4-5 Level 4 margin.
Availability
SMDJ78CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, and PoE-powered equipment requiring stable component supply, RoHS-compliant packaging, and MSL Level 1 reflow compatibility.
Supply support for SMDJ78CA 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 computing, consumer, industrial, and automotive markets.
The SMDJ78CA belongs to AOS's SMDJ series of high-power surface-mount TVS diodes, engineered specifically for robust transient immunity in harsh 24–48 V DC systems where reliability under repeated surge stress is critical.
FAQ
What is the clamping voltage of the SMDJ78CA under a 3000 W surge?
The SMDJ78CA clamps to a maximum of 126.0 V when subjected to its rated 3000 W peak pulse power (10/1000 µs waveform) at 23.9 A peak pulse current. This value is measured per JEDEC test conditions with 8.0 mm × 8.0 mm copper pads and represents the upper limit of voltage seen by downstream circuitry during surge events. The SMDJ78CA maintains this clamping performance consistently across its operating temperature range.
Is the SMDJ78CA unidirectional or bidirectional?
The SMDJ78CA is a bi-directional TVS diode, meaning it provides symmetrical clamping in both polarities. Unlike unidirectional variants (e.g., SMDJ78A), the 'CA' suffix explicitly denotes bidirectional functionality. This allows the SMDJ78CA to protect AC-coupled signals, floating power rails, or differential buses without regard to terminal orientation-both leads serve identical surge conduction roles.
What is the maximum junction temperature rating for the SMDJ78CA?
The SMDJ78CA has a maximum junction temperature (TJ max) of +150 °C, as specified in its Absolute Maximum Ratings table. This rating supports reliable operation in high-ambient environments such as engine compartments, industrial enclosures, and enclosed power supplies. Derating curves confirm usable power dissipation down to –55 °C, making the SMDJ78CA suitable for extended temperature range deployments.
Does the SMDJ78CA meet lead-free reflow requirements?
Yes, the SMDJ78CA meets lead-free reflow requirements with a J-STD-020 MSL Level 1 rating and a maximum peak reflow temperature of 260 °C. Its matte tin lead-free plating and UL 94V-0 flammability-compliant molding compound ensure compatibility with standard Pb-free assembly processes. The SMDJ78CA does not require pre-baking and may be placed directly into reflow ovens per IPC/JEDEC specifications.
How does the SMDJ78CA compare to the SMCJ78CA in terms of package and performance?
The SMDJ78CA and SMCJ78CA share identical DO-214AB (SMC J-Bend) packages, 78 V VRWM, 126 V clamping voltage, and 3000 W peak pulse power. Per published datasheets, their electrical characteristics-including VBR tolerance, leakage current, and thermal resistance-are functionally equivalent. The SMDJ78CA is a direct, pin-compatible alternative to SMCJ78CA with identical layout and thermal design requirements.
SMDJ78CA 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 23.9A
- 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
SMDJ78CA FAQ
1.How can I place an order for SMDJ78CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMDJ78CA 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 SMDJ78CA reliable?
The price and inventory of SMDJ78CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMDJ78CA is usually 5 days.
3.What payment methods are accepted for SMDJ78CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMDJ78CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMDJ78CA?
SMDJ78CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMDJ78CA 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 SMDJ78CA?
For technical support, including SMDJ78CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMDJ78CA requirements.
6.How does Aetrix verify that SMDJ78CA is sourced from the original manufacturer or authorized distributors?
All SMDJ78CA 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 SMDJ78CA meets industry standards.
7.What is the process for return or replacement of SMDJ78CA?
All SMDJ78CA units undergo pre-shipment inspection (PSI). If there is an issue with SMDJ78CA, 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 SMDJ78CA part is unused and in its original packaging.
Return procedure for SMDJ78CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMDJ78CA Tags
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