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Diodes Incorporated SMF4L12AQ-7
- Part No.:
- SMF4L12AQ-7
- Manufacturer:
- Diodes Incorporated
- Category:
- TVS Diodes
- Package:
- DO-219AA
- Datasheet:
-
SMF4L12AQ-7.pdf
- Description:
- TRANSIENT VOLTAGE SUPPRESSOR PP
- Quantity:
- Payment:
- Shipping:
Inventory:9,599
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Product details
Overview
SMF4L12AQ from Diodes Incorporated is a unidirectional transient voltage suppressor (TVS) diode designed for automotive-grade overvoltage protection in power rails and signal lines. It features a 12 V working peak reverse voltage (VRWM), 13.3–14.7 V breakdown voltage (VBR), 19.9 V maximum clamping voltage (VC) at 20.1 A peak pulse current, and 400 W peak pulse power dissipation (10/1000 µs waveform). It is AEC-Q101 qualified and used in battery contact protection and ECU power input stages.
For engineers reviewing the SMF4L12AQ datasheet, SMF4L12AQ pinout, SMF4L12AQ application, or SMF4L12AQ equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD, IEC 61000-4-2 ±30 kV ESD robustness, DO-219AA footprint compatibility, and thermal resistance (RθJA = 96 °C/W) under 1"×1" FR-4 layout constraints.
Technical Context
This TVS operates as a unidirectional clamp between power rail and ground, activating only during positive transients exceeding its VBR threshold. Its fast response time (<1.0 ns from 0 V to VBR) ensures suppression before downstream components experience overstress. The device uses planar junction silicon construction optimized for low capacitance and high surge current handling.
It is rated for 40 A peak forward surge current (8.3 ms half-sine), supports DC steady-state power dissipation of 1.0 W on standard PCB layout, and maintains operation across –55 °C to +175 °C ambient temperature range - critical for under-hood automotive deployment.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 12 V - Maximum continuous reverse voltage before leakage exceeds 0.5 µA; sets upper limit for safe operation on 12 V nominal systems. |
| VBR (min/max) | 13.3 V / 14.7 V - Breakdown occurs within this band at 1 mA test current; defines turn-on threshold consistency for design margining. |
| VC @ IPP | 19.9 V @ 20.1 A - Clamped voltage during 10/1000 µs surge; must stay below absolute max rating of protected ICs (e.g., <20 V for 24 V tolerant CAN transceivers). |
| PPK | 400 W - Peak pulse power handling per 10/1000 µs waveform; enables protection against ISO 7637-2 Pulse 1/2a/3a and IEC 61000-4-5 surges. |
| IR @ VRWM | 0.5 µA - Reverse leakage at 12 V; negligible loading on low-power sensor or microcontroller supply rails. |
| ESD Rating | ±30 kV (air/contact) per IEC 61000-4-2 - Ensures immunity to human-body-model discharges without external shielding. |
| Package | DO-219AA - Surface-mount, 2-pin, 1.9 mm × 2.8 mm footprint; compatible with automated SMT assembly and meets IPC-7351B density Class G. |
Pinout & Package
SMF4L12AQ is housed in a DO-219AA surface-mount package with two terminals: anode and cathode. The cathode is marked by a visible band on the top surface. This compact 2.8 mm × 1.9 mm molded plastic package features matte tin-plated copper alloy leads, UL 94V-0 flammability rating, and moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Power Rail Connection | Connected to protected line (e.g., 12 V battery feed); conducts during reverse-biased surge events when cathode is grounded. |
| Cathode | Ground Reference Terminal | Connected to system ground plane; establishes reference for clamping action and provides low-inductance return path for surge current. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive use including temperature cycling, HTRB, and surge testing per stress test plan - required for ECU, body control, and ADAS modules. |
| 400 W peak pulse power | Withstands ISO 7637-2 Pulse 1 (−150 V/2 Ω) and Pulse 2a (+100 V/50 Ω) without degradation when properly mounted on 2 oz. copper PCB. |
| Low clamping voltage (19.9 V) | Provides 7.9 V headroom below typical 28 V automotive load-dump thresholds, enabling direct protection of 24 V-rated interface ICs. |
| Fast response time (<1.0 ns) | Activates before transient energy couples into sensitive analog or digital circuitry - critical for protecting CAN FD or LIN transceivers. |
| Green, halogen-free construction | Meets RoHS 3 (2015/863/EU) and automotive ELV directive; bromine/chlorine <900 ppm each, antimony <1000 ppm - supports OEM sustainability compliance. |
Applications
| Battery Management System (BMS) Input Protection | Automotive Body Control Module (BCM) Power Rail |
|---|---|
|
Use Scenario: Protects BMS front-end monitoring ICs from load dump and jump-start transients on 12 V battery input. IC Role / Device Role / Timing Role: Unidirectional TVS clamps positive surges to ground while remaining high-impedance during normal 12 V operation. Use Value: Prevents latch-up or permanent damage to precision ADCs and voltage references by limiting clamped voltage to 19.9 V. |
Use Scenario: Shields microcontroller power pins and LIN transceiver VCC inputs from ignition-switching noise and alternator ripple. IC Role / Device Role / Timing Role: Fast-acting shunt element that diverts >20 A surge current away from 3.3 V/5 V LDO regulators and communication ICs. Use Value: Enables BCM designs to pass ISO 16750-2 electrical stress tests without adding bulkier TVS arrays or ferrite beads. |
| Infotainment Head Unit USB Power Port | ADAS Camera Module Power Line |
|
Use Scenario: Guards USB VBUS line against ESD events and hot-plug transients during vehicle service or accessory connection. IC Role / Device Role / Timing Role: Standoff-rated TVS placed upstream of USB power switch IC; blocks ±30 kV contact discharge per IEC 61000-4-2. Use Value: Eliminates need for secondary TVS or polymer PTC on USB port, reducing BOM count and PCB area in space-constrained head units. |
Use Scenario: Safeguards 12 V camera module power input against cable-discharge events and EMI-induced spikes in rear-view or surround-view systems. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main power rail, operating in parallel with ceramic decoupling capacitors to absorb nanosecond-scale transients. Use Value: Maintains image sensor uptime by preventing reset or brownout caused by transient-induced LDO dropout during parking maneuvers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A | Same DO-214AC package; higher RθJA (125 °C/W), lower PPK (400 W same), but VC = 20.1 V @ 20.2 A - slightly looser clamping margin. | Not AEC-Q101 qualified; limited to industrial/commercial automotive after-market use. | Select when cost is prioritized over automotive qualification and board-level thermal management allows higher junction rise. |
| SMBJ12A | DO-214AA package; larger footprint (4.5 mm × 3.9 mm); identical electrical specs but 3× higher thermal mass - slower transient response (~1.2 ns). | Preferred where mechanical robustness and manual rework tolerance outweigh space constraints. | Choose for prototyping or low-volume assemblies where DO-219AA pick-and-place capability is unavailable. |
Compared with SMAJ12A and SMBJ12A, SMF4L12AQ delivers tighter clamping (19.9 V vs. 20.1 V), superior thermal performance (RθJA = 96 °C/W), and full AEC-Q101 compliance - making it the optimal choice for production automotive ECUs requiring zero-defect reliability and compact layout.
Availability
SMF4L12AQ is available at Aetrix Electronics and suitable for automotive electronic control units, battery management systems, and infotainment power supplies requiring stable component supply across multi-year production cycles.
Supply support for SMF4L12AQ 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 centers and manufacturing facilities across Asia and the Americas.
The SMF4L series belongs to Diodes' automotive-grade TVS portfolio, engineered specifically for high-reliability transient suppression in harsh environments - targeting ISO 16750-2, ISO 7637-2, and AEC-Q101-compliant applications.
FAQ
What is the polarity configuration of SMF4L12AQ?
SMF4L12AQ is a unidirectional TVS diode, with cathode denoted by a visible band on the top surface of the DO-219AA package. It conducts only during positive voltage transients applied to the anode relative to cathode, making it suitable for DC power rail protection where reverse polarity is not expected.
How does SMF4L12AQ perform under high-temperature operating conditions?
SMF4L12AQ is rated for junction temperatures from –55 °C to +175 °C and exhibits derated peak pulse power above +25 °C per Figure 1 in DS43393. At +125 °C ambient, its 400 W PPK drops to ~260 W, while leakage remains ≤1.0 µA - validated for under-hood engine control module deployments.
Can SMF4L12AQ replace older SMAJ12A devices in existing designs?
Yes, SMF4L12AQ is a drop-in replacement for SMAJ12A in terms of electrical specs and PCB layout, but requires verification of solder profile due to smaller DO-219AA package mass. Its lower RθJA improves thermal margin, and AEC-Q101 qualification adds reliability assurance not present in SMAJ12A.
What is the typical junction capacitance of SMF4L12AQ at 0 V bias?
Per Diodes' characterization data, SMF4L12AQ exhibits ~120 pF typical junction capacitance at 0 V bias and 1 MHz - measured on the unidirectional variant. This value supports signal integrity in low-speed power-line applications but is unsuitable for high-frequency data lines like USB 2.0 or CAN FD without additional filtering.
SMF4L12AQ-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):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 20.1A
- 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
SMF4L12AQ-7 FAQ
1.How can I place an order for SMF4L12AQ-7 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF4L12AQ-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 SMF4L12AQ-7 reliable?
The price and inventory of SMF4L12AQ-7 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF4L12AQ-7 is usually 5 days.
3.What payment methods are accepted for SMF4L12AQ-7?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF4L12AQ-7 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF4L12AQ-7?
SMF4L12AQ-7 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF4L12AQ-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 SMF4L12AQ-7?
For technical support, including SMF4L12AQ-7 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF4L12AQ-7 requirements.
6.How does Aetrix verify that SMF4L12AQ-7 is sourced from the original manufacturer or authorized distributors?
All SMF4L12AQ-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 SMF4L12AQ-7 meets industry standards.
7.What is the process for return or replacement of SMF4L12AQ-7?
All SMF4L12AQ-7 units undergo pre-shipment inspection (PSI). If there is an issue with SMF4L12AQ-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 SMF4L12AQ-7 part is unused and in its original packaging.
Return procedure for SMF4L12AQ-7:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF4L12AQ-7 Tags
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