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Diodes Incorporated SMAJ78AQ-13-F
- Part No.:
- SMAJ78AQ-13-F
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78AQ-13-F.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR SMA
- Quantity:
- Payment:
- Shipping:
Inventory:5,813
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Product details
Overview
SMAJ78AQ-13-F from Diodes Incorporated is a unidirectional 400W automotive transient voltage suppressor (TVS) diode with 78V reverse standoff voltage, 126V max clamping voltage at 3.2A peak pulse current, and AEC-Q101 qualification for under-hood electronics protection against ISO7637-2 Pulse 1/2a/3a/3b and ISO10605 ESD events.
For engineers reviewing the SMAJ78AQ-13-F datasheet, SMAJ78AQ-13-F pinout, SMAJ78AQ-13-F application, or SMAJ78AQ-13-F equivalent, this device serves as a primary surge protection component in 12V/24V automotive power rails, battery management interfaces, and LIN/CAN transceiver I/O lines where precise clamping, low leakage (<0.5µA @ 78V), and high surge robustness are required.
Technical Context
This unidirectional TVS diode operates as a voltage-clamped shunt protector: it remains high-impedance below 78V VRWM, breaks down sharply between 86.7V–95.8V at 1mA IT, and clamps transients to ≤126V at 3.2A IPP under 10×1000μs waveform. Its glass-passivated die ensures stable breakdown characteristics across -55°C to +175°C junction temperature.
Designed for automotive-grade reliability, it delivers 400W non-repetitive peak pulse power per IEC 61000-4-5, supports 40A IFSM surge current (8.3ms half-sine), and maintains <0.5µA IR at VRWM - critical for low-power always-on circuits like body control modules and telematics wake-up inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 78V - Maximum continuous reverse operating voltage before clamping begins; sets minimum system overvoltage threshold. |
| VBR (min/max) | 86.7V / 95.8V @ 1mA - Confirmed breakdown range ensures predictable turn-on without premature conduction. |
| VC @ IPP | 126V @ 3.2A - Clamping voltage under standardized 10×1000μs surge; defines worst-case voltage seen by protected ICs. |
| PPK | 400W - Peak pulse power handling per single transient; enables compliance with ISO7637-2 Pulse 1 (-100V) and Pulse 3a (-150V). |
| IR @ VRWM | <0.5µA - Ultra-low reverse leakage preserves battery life in always-on vehicle networks (e.g., CAN FD sleep mode). |
| IFSM | 40A - Surge current rating for 8.3ms half-sine wave; validates robustness against alternator load dump events. |
| TJ Range | -55°C to +175°C - Full automotive temperature range support for engine bay and transmission control unit placement. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, molded plastic UL 94V-0 housing; cathode band indicates polarity on unidirectional variant; moisture sensitivity level 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-impedance return path; completes clamping loop during positive transients. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 12V rail); conducts surge current to ground when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 400W peak pulse power | Validated for ISO7637-2 Pulse 1 (-100V), Pulse 2a (+50V), and Pulse 3a (-150V) without degradation. |
| AEC-Q101 qualified | Qualified for automotive use with PPAP capability and manufacturing in IATF 16949 certified facilities. |
| Glass passivated die | Ensures stable VBR and low leakage across thermal cycling and humidity exposure in under-hood environments. |
| Lead-free & halogen-free | RoHS 3 compliant (2015/863/EU); Br+Cl <1500ppm, Sb <1000ppm - meets global automotive environmental requirements. |
Applications
| Engine Control Unit (ECU) Power Input | Body Control Module (BCM) LIN Bus Line |
|---|---|
Use Scenario: Protects 12V supply rail of gasoline/diesel ECUs from load dump surges and alternator ripple. IC Role / Device Role / Timing Role: Shunt clamping TVS placed directly at ECU input connector to limit voltage to ≤126V during ISO7637-2 Pulse 1 (-100V) events. Use Value: Prevents damage to downstream DC-DC converters and microcontrollers by clamping transients within safe operating area of 78V-rated components. |
Use Scenario: Shields LIN transceiver I/O pins from ESD events during service port connection/disconnection. IC Role / Device Role / Timing Role: Fast-response unidirectional clamp on LIN bus line, activated within nanoseconds of 30kV contact discharge (ISO10605). Use Value: Maintains signal integrity with <0.5µA leakage at 12V nominal, avoiding false wake-ups or communication errors in low-power LIN sleep states. |
| Advanced Driver Assistance Systems (ADAS) Camera Power | Electric Power Steering (EPS) Motor Driver Interface |
Use Scenario: Guards 5V/12V camera module power input against ignition-induced transients in front-end ADAS sensors. IC Role / Device Role / Timing Role: Primary overvoltage clamp upstream of LDO regulators, responding to 10×1000μs surges with ≤126V clamping. Use Value: Enables uninterrupted video capture by preventing reset or latch-up of image sensor ASICs during road vibration-induced electrical noise. |
Use Scenario: Protects H-bridge gate driver supply rails from inductive kickback during EPS motor commutation. IC Role / Device Role / Timing Role: High-energy (400W) shunt device absorbing repetitive 8.3ms surges up to 40A IFSM during steering actuation cycles. Use Value: Extends gate driver IC lifetime by limiting voltage stress on bootstrap capacitors and level-shift circuits during rapid motor direction changes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional automotive TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A-13-F | Non-AEC-Q101 version; identical electrical specs but lacks automotive change control and PPAP documentation. | Acceptable for non-safety-critical industrial or consumer designs; not approved for OEM automotive BOMs. | Select only if automotive qualification is not required and cost optimization is prioritized. |
| TPSMD78A | Same 78V VRWM and 126V VC, but rated for 600W PPK and higher 50A IFSM; larger SMB package (4.5 × 3.9 mm vs SMA 4.5 × 2.7 mm). | Better suited for high-energy load dump scenarios; requires PCB layout revision due to larger footprint and thermal pad. | Choose when system-level testing reveals margin不足 in 400W clamping or when board space allows SMB upgrade. |
Compared with SMAJ78A-13-F, this part adds AEC-Q101 traceability and production controls; versus TPSMD78A, it trades peak power headroom for compact SMA footprint and lower assembly cost in space-constrained modules.
Availability
SMAJ78AQ-13-F is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera systems, and electric power steering interfaces requiring stable component supply across automotive production lifecycles.
Supply support for SMAJ78AQ-13-F 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 semiconductor manufacturer specializing in discrete, analog, and mixed-signal solutions for automotive, industrial, and computing markets.
This device belongs to the SMAJ(AQ) series - engineered specifically for AEC-Q101-compliant transient suppression in 12V/24V automotive power domains, with emphasis on ISO7637-2 and ISO10605 compliance.
FAQ
What is the maximum clamping voltage of SMAJ78AQ-13-F under standard test conditions?
The maximum clamping voltage (VC) is 126V at 3.2A peak pulse current (IPP), measured using the 10×1000μs waveform defined in IEC 61000-4-5. This value is guaranteed across the full operating temperature range (-55°C to +175°C) and represents the upper voltage limit imposed on protected circuitry during surge events.
Is SMAJ78AQ-13-F suitable for bi-directional signal line protection?
No - SMAJ78AQ-13-F is unidirectional, indicated by the absence of "C" in its part number. It protects only positive-going transients on lines referenced to ground. For bi-directional protection (e.g., data lines with AC signals), the SMAJ78CAQ-13-F variant must be used, which has symmetrical clamping for both polarities.
How does the AEC-Q101 qualification impact design validation for automotive applications?
AEC-Q101 qualification confirms that SMAJ78AQ-13-F has passed stress tests including HTOL, TC, UHAST, and ESD, with full PPAP documentation and IATF 16949 manufacturing controls. This eliminates need for redundant qualification testing by Tier 1 suppliers and satisfies OEM requirements for component-level reliability in safety-critical systems.
What is the thermal derating behavior above +25°C ambient?
Peak pulse power (PPK) is derated linearly above +25°C ambient: at +85°C TA, PPK drops to ~280W; at +125°C, it falls to ~160W. Steady-state power dissipation (PM(AV)) is limited to 1.0W at TL = +75°C, with full derating to zero at +175°C lead temperature per Figure 6 in DS40739.
SMAJ78AQ-13-F Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 3.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
SMAJ78AQ-13-F FAQ
1.How can I place an order for SMAJ78AQ-13-F through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78AQ-13-F 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 SMAJ78AQ-13-F reliable?
The price and inventory of SMAJ78AQ-13-F are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78AQ-13-F is usually 5 days.
3.What payment methods are accepted for SMAJ78AQ-13-F?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78AQ-13-F transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78AQ-13-F?
SMAJ78AQ-13-F orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78AQ-13-F 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 SMAJ78AQ-13-F?
For technical support, including SMAJ78AQ-13-F datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78AQ-13-F requirements.
6.How does Aetrix verify that SMAJ78AQ-13-F is sourced from the original manufacturer or authorized distributors?
All SMAJ78AQ-13-F 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 SMAJ78AQ-13-F meets industry standards.
7.What is the process for return or replacement of SMAJ78AQ-13-F?
All SMAJ78AQ-13-F units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78AQ-13-F, 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 SMAJ78AQ-13-F part is unused and in its original packaging.
Return procedure for SMAJ78AQ-13-F:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ78AQ-13-F Tags
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