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Taiwan Semiconductor Corporation SMF12A
- Part No.:
- SMF12A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- SOD-123W
- Datasheet:
-
SMF12A.pdf
- Description:
- TVS DIODE 12VWM 19.9VC SOD123W
- Quantity:
- Payment:
- Shipping:
Inventory:18,699
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Product details
Overview
SMF12A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy ESD and surge protection in low-voltage DC circuits. It features a 12 V working stand-off voltage (VWM), 13.3–14.7 V breakdown voltage (VBR), 19.9 V clamping voltage (VC) at 10.1 A peak pulse current, and 200 W peak pulse power (10/1000 µs). It is commonly used to protect automotive body electronics, USB power rails, and industrial sensor interfaces.
For engineers reviewing the SMF12A datasheet, SMF12A pinout, SMF12A application, or SMF12A equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, low leakage (<1 µA @ 12 V), SOD-123W package compatibility with automated assembly, and thermal robustness up to +175 °C junction temperature.
Technical Context
The SMF12A operates as a unidirectional avalanche diode, conducting only in reverse bias above its breakdown threshold to shunt transient energy away from protected circuitry. Its glass-passivated junction ensures stable VBR tolerance and low leakage, while its SOD-123W package provides enhanced thermal dissipation (RθJL = 33 °C/W) over standard SOD-123.
It meets ISO 7637-2 immunity requirements for automotive load-dump and inductive switching transients, with specified clamping behavior validated under standardized 10/1000 µs waveform testing. The device is rated for non-repetitive peak impulse power of 200 W and steady-state power dissipation of 1 W on a 5 mm × 5 mm copper pad PCB.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 13.3 V / 14.7 V - Breakdown occurs within this range at 1 mA test current, defining turn-on threshold |
| VC @ IPPM | 19.9 V - Clamped voltage across SMF12A during 10.1 A 10/1000 µs surge, limiting stress on downstream ICs |
| PPPM | 200 W - Peak transient power handling capability, enabling protection against severe EFT and load-dump events |
| IR @ VWM | <1 µA - Negligible reverse leakage at operating voltage, avoiding signal integrity or battery drain issues |
| TJ max | +175 °C - Maximum junction temperature rating supports under-hood automotive and industrial environments |
| Package | SOD-123W - Robust surface-mount outline with improved thermal performance vs. standard SOD-123 |
Pinout & Package
SMF12A uses the SOD-123W package: a surface-mount, single-diode, unidirectional configuration with cathode indicated by a band. The package features matte tin-plated leads, UL 94V-0 molding compound, and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., GND or return path) in unidirectional TVS configuration |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 12 V rail); conducts when transient exceeds VBR, shunting current to anode |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures tight VBR tolerance (±5%), stable leakage, and long-term reliability under thermal cycling |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (EFT), critical for automotive ECUs |
| Low clamping ratio (VC/VBR ≈ 1.4) | Minimizes overvoltage exposure to protected ICs-e.g., 19.9 V clamping at 13.3 V nominal breakdown |
| Moisture sensitivity level 1 | Enables direct placement without baking, reducing manufacturing cost and process complexity |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and global environmental regulations for industrial and automotive supply chains |
Applications
| Automotive Body Control Module (BCM) | USB Type-C Power Delivery Rail |
|---|---|
Use Scenario: Protecting LIN bus transceivers and door module microcontrollers from load-dump surges and battery reversal transients. IC Role / Device Role: Unidirectional TVS placed between 12 V supply and ground, clamping transients before they reach sensitive analog front-ends. Use Value: Limits voltage to ≤19.9 V during 10/1000 µs 10.1 A surge, preventing latch-up or permanent damage to 5 V or 3.3 V logic ICs. | Use Scenario: Safeguarding 5 V/9 V/15 V PD power lines against ESD and hot-swap transients during plug insertion/removal. IC Role / Device Role: Primary overvoltage clamp on VBUS line, positioned upstream of buck converters and USB-PD controllers. Use Value: Sub-1 µA leakage avoids standby current penalty; fast response (<1 ns) prevents voltage overshoot beyond USB-PD specification limits. |
| Industrial Sensor Signal Conditioning | Smart Lighting LED Driver Input Stage |
Use Scenario: Shielding 4–20 mA loop-powered sensors from induced surges on field wiring in factory automation systems. IC Role / Device Role: Reverse-biased TVS across input terminals, referenced to local ground, absorbing common-mode transients. Use Value: 12 V VWM allows operation across full 24 V system range while maintaining margin; 175 °C TJ rating supports enclosed enclosures. | Use Scenario: Protecting constant-current LED drivers from inductive kickback during MOSFET switching and AC line transients. IC Role / Device Role: Clamp diode on DC input bus (e.g., 24–48 V), diverting surge current away from driver ICs and electrolytic capacitors. Use Value: 200 W PPPM handles repetitive switching spikes; SOD-123W thermal performance sustains reliability under high ambient temperatures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ12A (Bourns) | Same VWM (12 V), but SMB package (larger footprint, RθJA = 50 °C/W vs. SMF12A's 100 °C/W) | Better suited for higher-power, lower-density layouts where board space permits larger package | Choose SMBJ12A if thermal margin is constrained and PCB area allows SMB outline |
| P6SMB12A (ON Semiconductor) | Identical electrical specs (VWM=12 V, VC=19.9 V), but legacy SMB package and slightly higher IR (≤5 µA vs. <1 µA) | Acceptable where ultra-low leakage is not required (e.g., non-battery-powered systems) | Choose P6SMB12A if sourcing legacy BOMs or cost-sensitive non-automotive designs |
Compared with SMBJ12A and P6SMB12A, SMF12A offers superior leakage performance and smaller SOD-123W footprint-critical for space-constrained automotive modules-while delivering identical clamping behavior and ISO 7637-2 compliance.
Availability
SMF12A is available at Aetrix Electronics and suitable for automotive body electronics, USB power delivery systems, industrial sensor interfaces, and smart lighting driver inputs requiring stable component supply and full production traceability.
Supply support for SMF12A 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs, with global distribution and AEC-Q200 qualified product lines.
The SMF series was developed specifically for high-reliability, surface-mount transient suppression in automotive and industrial environments-emphasizing low leakage, precise VBR control, and robust ISO 7637-2 compliance in compact packages.
FAQ
What is the maximum clamping voltage of SMF12A under a 10/1000 µs surge?
The SMF12A clamps to a maximum of 19.9 V when subjected to its rated peak pulse current of 10.1 A with a 10/1000 µs waveform. This value is measured per JEDEC standards and guarantees that protected downstream components experience no more than 19.9 V during such transients-critical for safeguarding 3.3 V or 5 V logic ICs. The clamping voltage is confirmed in the Electrical Specifications table on page 3 of the SMF5.0A–SMF100A datasheet revision D2103.
Does SMF12A meet automotive transient immunity standards?
Yes, SMF12A meets ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (supply interruption and switching transients), and Pulse 3a/3b (electrical fast transients), as explicitly stated in the Features section of the datasheet. Its 200 W peak pulse power rating and verified clamping behavior under standardized waveforms make it suitable for automotive body control modules, infotainment power supplies, and sensor interfaces per AEC-Q200 stress test alignment.
What is the reverse leakage current of SMF12A at its working voltage?
The SMF12A exhibits a maximum reverse leakage current of less than 1 µA at its 12 V working stand-off voltage (VWM), tested at TA = 25°C. This ultra-low leakage minimizes standby power loss in battery-operated systems and avoids false triggering in high-impedance sensing nodes. The value is specified in the Electrical Specifications table and confirmed across the full operating temperature range up to +125°C.
Is SMF12A unidirectional or bidirectional, and how does polarity affect layout?
SMF12A is a unidirectional TVS diode, meaning it clamps only in reverse bias and conducts forward like a standard diode. Polarity is marked by a cathode band; the cathode must be connected to the line being protected (e.g., 12 V rail), and the anode to ground. Incorrect orientation will prevent clamping during negative transients and may cause forward conduction during normal operation-so correct placement per the marking diagram in the Package Outline section is essential.
What is the thermal resistance profile of SMF12A, and how does it impact PCB design?
SMF12A has a junction-to-lead thermal resistance (RθJL) of 33 °C/W and junction-to-ambient resistance (RθJA) of 100 °C/W when mounted on a 5 mm × 5 mm copper pad. These values indicate efficient heat transfer to the PCB, allowing sustained operation under repeated surges. To maintain reliability, designers should use minimum 5 mm² copper pour under the SOD-123W footprint and avoid narrow traces-especially for the cathode connection carrying peak surge current.
SMF12A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- SOD-123W
- Series:
- SMF
- 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):
- 10.1A
- Power - Peak Pulse:
- 200W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123W
SMF12A FAQ
1.How can I place an order for SMF12A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF12A 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 SMF12A reliable?
The price and inventory of SMF12A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF12A is usually 5 days.
3.What payment methods are accepted for SMF12A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF12A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF12A?
SMF12A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF12A 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 SMF12A?
For technical support, including SMF12A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF12A requirements.
6.How does Aetrix verify that SMF12A is sourced from the original manufacturer or authorized distributors?
All SMF12A 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 SMF12A meets industry standards.
7.What is the process for return or replacement of SMF12A?
All SMF12A units undergo pre-shipment inspection (PSI). If there is an issue with SMF12A, 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 SMF12A part is unused and in its original packaging.
Return procedure for SMF12A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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