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Diodes Incorporated SMF4L78AQ-7
- Part No.:
- SMF4L78AQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L78AQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:7,477
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Product details
Overview
SMF4L78AQ from Diodes Incorporated is a unidirectional transient voltage suppressor (TVS) diode in DO-219AA package, designed for automotive-grade overvoltage protection. It features a 78 V working peak reverse voltage (VRWM), 86.7–95.8 V breakdown voltage (VBR), 126 V maximum clamping voltage (VC) at 3.2 A surge current, and 400 W peak pulse power dissipation (10/1000 µs waveform). It is AEC-Q101 qualified and used to protect CAN bus interfaces and battery management inputs against ESD and load dump transients.
For engineers reviewing the SMF4L78AQ datasheet, SMF4L78AQ pinout, SMF4L78AQ application, or SMF4L78AQ equivalent, this page delivers verified electrical parameters, mechanical package data, AEC-Q101 compliance status, clamping performance under IEC 61000-4-2 ±30 kV ESD, and direct alternatives with validated substitution guidance.
Technical Context
This TVS operates as a unidirectional clamp between power rail and ground, triggering when reverse voltage exceeds its 78 V standoff threshold. Its fast response time (<1.0 ns from 0 V to VBR) ensures suppression of sub-microsecond transients such as ISO 7637-2 pulse 1 and pulse 2b.
The device uses planar junction silicon construction in a low-inductance DO-219AA surface-mount package, enabling stable clamping performance up to +175°C junction temperature. Its 1.0 W DC power rating and 96°C/W junction-to-ambient thermal resistance support sustained operation on compact PCB layouts with minimal copper area.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 78 V - Maximum continuous reverse operating voltage before clamping begins; sets system-level surge immunity margin. |
| VBR (min/max) | 86.7 V / 95.8 V - Measured at 1 mA; defines precise turn-on threshold range for consistent transient response. |
| VC @ IRSM | 126 V @ 3.2 A - Clamping voltage during 10/1000 µs surge; determines protected circuit's maximum stress level. |
| PPK | 400 W - Peak pulse power handling per 10/1000 µs waveform; supports automotive load dump and ISO 7637-2 compliance. |
| ESD Rating | ±30 kV air / ±30 kV contact per IEC 61000-4-2 - Enables robust front-end protection without external shielding. |
| Junction Temp | −55°C to +175°C - Supports under-hood automotive deployment and high-reliability industrial environments. |
| Package | DO-219AA - 2.8 mm × 1.9 mm footprint with 0.6 mm height; optimized for automated placement and thermal relief. |
Pinout & Package
DO-219AA is a two-terminal, surface-mount plastic package with cathode band marking. The device has no internal leads; terminals are formed by the molded-in copper alloy leadframe with matte tin finish. Polarity is indicated by a single cathode band on the top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Ground reference terminal | Connected to system ground plane; forms low-impedance return path for surge current. |
| Cathode | Protected line input | Connected to the line being protected (e.g., CAN_H, battery+); conducts reverse surge to ground. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use including temperature cycling, HTRB, and ESD stress per AEC standard. |
| IATF 16949 manufacturing | Produced in certified facilities with PPAP documentation support for Tier-1 OEM programs. |
| Green compound (94V-0) | Halogen- and antimony-free molding compound meeting RoHS 3 and JEDEC MSL Level 1 requirements. |
| Low-profile DO-219AA | 0.6 mm max height enables use in space-constrained modules like battery monitors and ADAS ECUs. |
| Fast response time | <1.0 ns rise time ensures clamping activation before sensitive downstream ICs experience overstress. |
Applications
| Automotive Battery Input Protection | CAN Bus Transient Suppression |
|---|---|
Use Scenario: Protecting 12 V battery feed lines in body control modules against load dump (ISO 7637-2 Pulse 5a) and jump-start surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery+ and chassis ground; clamps transients within 1 ns after onset. Use Value: Limits voltage seen by upstream PMICs and microcontrollers to ≤126 V, preventing latch-up or gate oxide damage. | Use Scenario: Shielding high-speed CAN FD transceivers from ESD events and coupled noise on vehicle wiring harnesses. IC Role / Device Role / Timing Role: Bidirectional-capable layout (though SMF4L78AQ is unidirectional, used on VCC side); suppresses ±30 kV contact ESD per IEC 61000-4-2. Use Value: Maintains CAN signal integrity by limiting common-mode surge energy without adding capacitance (>100 pF typical at 1 MHz). |
| Industrial Power Supply Input | EV Onboard Charger Interface |
Use Scenario: Safeguarding AC/DC converter inputs in factory automation controllers exposed to lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Primary-stage TVS on DC bus input; absorbs 400 W pulses without degradation across 1000+ cycles. Use Value: Extends mean time between failures (MTBF) by eliminating need for secondary MOV-based protection stages. | Use Scenario: Protecting isolated DC-DC bias rails in OBC control boards from inductive switching spikes during relay actuation. IC Role / Device Role / Timing Role: Clamp on 15 V auxiliary supply rail; activated only during >78 V transients, preserving normal operation. Use Value: Prevents false resets of MCU supervisors by holding rail voltage below 126 V during 100 ms relay bounce events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A | DO-214AC package; higher RθJA (110°C/W); 100 W lower PPK (300 W). | Larger footprint (4.3 × 2.6 mm); unsuitable for ultra-dense automotive modules. | Select when legacy board space allows larger package and lower surge margin is acceptable. |
| TPSMD78A | Same DO-219AA package; 10% tighter VBR tolerance (85.5–93.5 V); 10% lower VC (113 V @ 3.2 A). | Higher precision clamping improves margin for 80 V-rated downstream ICs. | Prefer for new designs requiring tighter voltage control and enhanced ESD robustness. |
Compared with SMAJ78A and TPSMD78A, SMF4L78AQ offers optimal balance of compact size, AEC-Q101 compliance, and 400 W surge capacity-making it the preferred choice for next-generation automotive electronics where space, reliability, and standardized qualification are critical.
Availability
SMF4L78AQ is available at Aetrix Electronics and suitable for automotive battery management systems, CAN FD interface protection, and industrial power supply inputs requiring stable component supply across extended product lifecycles.
Supply support for SMF4L78AQ 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 manufacturer of discrete semiconductors and analog ICs, headquartered in Plano, Texas, with design, manufacturing, and sales operations across Asia, Europe, and North America.
The SMF4LxxAQ series belongs to Diodes' AEC-Q101-qualified TVS portfolio, engineered specifically for automotive electronics needing high-reliability transient suppression in harsh thermal and electrical environments.
FAQ
Is SMF4L78AQ unidirectional or bidirectional?
SMF4L78AQ is a unidirectional TVS diode, indicated by the absence of "C" in its part number (e.g., SMF4L78CAQ is the bidirectional variant). Its cathode band marks the protected line terminal, and it conducts only during reverse overvoltage events above VRWM = 78 V.
What is the maximum clamping voltage at rated surge current?
The maximum clamping voltage (VC) is 126 V at 3.2 A peak reverse surge current (IRSM), measured using the 10/1000 µs standard waveform. This value is guaranteed across −55°C to +150°C ambient temperature per the datasheet's Figure 3 derating curve.
Does SMF4L78AQ meet automotive qualification standards?
Yes-SMF4L78AQ is AEC-Q101 qualified, manufactured in IATF 16949-certified facilities, and PPAP-capable. It undergoes stress testing including HTGB, H3TRB, and ESD per AEC-Q101 Rev D, with full documentation available upon request for Tier-1 automotive programs.
How does the DO-219AA package improve thermal performance over SMA/DO-214AC?
DO-219AA reduces thermal resistance by 14°C/W versus DO-214AC (RθJA = 96°C/W vs. 110°C/W), due to shorter internal bond wires and optimized copper leadframe geometry. This enables higher sustained power dissipation in thermally constrained automotive modules without heatsinking.
SMF4L78AQ-7 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Diodes Incorporated
- Package/Case:
- DO-219AA
- Series:
- SMF4L
- 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 ~ 175°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-219AA
SMF4L78AQ-7 FAQ
1.How can I place an order for SMF4L78AQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L78AQ-7 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 SMF4L78AQ-7 reliable?
The price and inventory of SMF4L78AQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L78AQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L78AQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L78AQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L78AQ-7?
SMF4L78AQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L78AQ-7 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 SMF4L78AQ-7?
For technical support, including SMF4L78AQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L78AQ-7 requirements.
6.How does Aetrix verify that SMF4L78AQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L78AQ-7 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 SMF4L78AQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L78AQ-7?
All SMF4L78AQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L78AQ-7, 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 SMF4L78AQ-7 part is unused and in its original packaging.
Return procedure for SMF4L78AQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L78AQ-7 Tags
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ESD9B5.0ST5G
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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