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Taiwan Semiconductor Corporation SMA4F12AH
- Part No.:
- SMA4F12AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-221AC, SMA Flat Leads
- Datasheet:
-
SMA4F12AH.pdf
- Description:
- 400W, 14.1V, 5%, UNIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:6,845
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Product details
Overview
SMA4F12AH from Taiwan Semiconductor is a unidirectional, AEC-Q101-qualified transient voltage suppressor (TVS) diode in a Thin SMA package, with 12 V working stand-off voltage (VWM), 13.4–14.8 V breakdown voltage (VBR), 400 W peak pulse power (PPPM), and 19.5 V clamping voltage (VC) at 20.5 A peak impulse current. It protects automotive BLDC motor drives and battery management systems against ESD and surge transients.
For engineers reviewing the SMA4F12AH datasheet, SMA4F12AH pinout, SMA4F12AH application, or SMA4F12AH equivalent, key selection criteria include unidirectional polarity, 175 °C max junction temperature, J-STD-020 Level 1 moisture sensitivity, UL 94V-0 molding compound, and compatibility with reflow soldering per J-STD-002.
Technical Context
This TVS diode uses a glass-passivated silicon junction optimized for fast response to transients up to 10/1000 µs waveform. Its thermal design supports 20 °C/W junction-to-lead resistance and operates across –55 °C to +175 °C ambient range.
The device is rated for 7.5 W steady-state power dissipation on a 5 mm × 5 mm copper pad PCB, with forward voltage of 3.5 V at 25 A - confirming robust conduction capability during clamping events without latch-up.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 13.4 V / 14.8 V - verified breakdown threshold at 1 mA test current, ensuring precise overvoltage triggering |
| VC @ IPPM | 19.5 V - clamping voltage at 20.5 A peak impulse, limiting downstream circuit stress during surge |
| PPPM | 400 W - peak pulse power handling for 10/1000 µs waveform, meeting IEC 61000-4-5 Level 4 |
| TJ max | +175 °C - extended junction temperature rating enabling under-hood automotive deployment |
| RθJL | 20 °C/W - low junction-to-lead thermal resistance supporting reliable power dissipation on standard PCB pads |
Pinout & Package
Thin SMA package: surface-mount, unidirectional configuration with cathode band marking; case meets UL 94V-0, leads matte tin-plated per J-STD-002, weight ≈ 0.030 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current sink input | Connected to protected line; conducts surge current toward ground when V > VBR |
| Cathode | Reference/ground return | Marked by band; ties to system ground or low-impedance return path for clamping loop integrity |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per stress requirements |
| Glass passivated junction | Enhances long-term stability and leakage immunity in humid or high-bias environments |
| VBR tempco ≤ 0.095%/°C | Minimizes voltage drift over temperature, preserving clamping accuracy across –40 °C to +125 °C operating range |
| J-STD-020 Level 1 MSL | Enables standard SMT reflow without baking or special handling prior to assembly |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive for environmentally constrained supply chains |
Applications
| BLDC Motor Drive Protection | Battery Management System (BMS) |
|---|---|
Use Scenario: Suppresses inductive kickback and load dump transients in 12 V automotive BLDC gate driver circuits. IC Role / Device Role / Timing Role: Unidirectional TVS placed across motor phase lines or between gate driver output and ground. Use Value: Clamps spikes to ≤19.5 V within nanoseconds, preventing MOSFET avalanche failure and maintaining PWM timing integrity. | Use Scenario: Shields cell monitoring ICs and communication interfaces in 12 V Li-ion BMS modules from ISO 7637-2 pulse 1/2a/5a surges. IC Role / Device Role / Timing Role: Standoff protection element on main power rail and CAN bus lines. Use Value: Limits transient overshoot below 20 V while sustaining <1 µA leakage at 12 V, preserving low-power sleep mode current budgets. |
| Automotive Lighting Control | Switching Mode Power Supply (SMPS) |
Use Scenario: Guards LED driver ICs and microcontrollers in headlamp modules against load dump and jump-start transients. IC Role / Device Role / Timing Role: Primary rail clamp on 12 V input stage upstream of DC-DC converter. Use Value: Withstands 400 W pulses without degradation, ensuring functional safety compliance (ISO 26262 ASIL-B support via AEC-Q101). | Use Scenario: Protects primary-side controller and secondary-side rectifiers in 12 V output flyback converters used in infotainment supplies. IC Role / Device Role / Timing Role: Input rail TVS parallel to bulk capacitor, absorbing line-induced surges before regulation stage. Use Value: 19.5 V clamping ensures downstream regulator remains within absolute maximum ratings during 10/1000 µs transients. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ12A | Same Thin SMA package, 12 V VWM, but lower PPPM (400 W same), higher VC (20.1 V), non-AEC-Q101 | Not qualified for automotive under-hood use; suitable for industrial SMPS only | Select SMA4F12AH where AEC-Q101 compliance and tighter VBR tolerance (±5.3%) are required |
| Vishay SMA6J12A | Same footprint, 12 V VWM, 400 W PPPM, but VBR range wider (13.3–15.8 V), no AEC-Q101, MSL Level 1 confirmed | Lacks automotive qualification; higher VBR variation increases risk of premature clamping in precision 12 V rails | Prefer SMA4F12AH for BLDC and BMS where stable breakdown and automotive traceability are mandatory |
Compared with SMAJ12A and SMA6J12A, the SMA4F12AH delivers tighter VBR control, guaranteed AEC-Q101 qualification, and lower clamping voltage - directly improving surge margin in safety-critical 12 V automotive subsystems without layout change.
Availability
SMA4F12AH is available at Aetrix Electronics and suitable for automotive BLDC motor drives, battery management systems, lighting control units, and switching mode power supplies requiring stable component supply across extended temperature and lifecycle demands.
Supply support for SMA4F12AH 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in power devices, TVS diodes, and automotive-qualified components.
The SMA4FxxAH series was developed specifically for AEC-Q101-compliant transient protection in 12–60 V automotive power networks, emphasizing thermal robustness, tight parametric control, and reflow-ready packaging.
FAQ
What is the exact breakdown voltage range for SMA4F12AH?
The SMA4F12AH has a guaranteed breakdown voltage (VBR) range of 13.4 V to 14.8 V at 1 mA test current (IT), measured per JEDEC standards. This narrow ±5.3% tolerance ensures consistent clamping behavior across production lots and temperature extremes, critical for protecting sensitive 12 V automotive electronics without false triggering.
Is SMA4F12AH compatible with lead-free reflow soldering processes?
Yes, SMA4F12AH is fully compatible with lead-free reflow soldering. Its matte tin-plated leads meet J-STD-002 solderability requirements, and its MSL Level 1 rating per J-STD-020 means it can be processed using standard IPC/JEDEC profiles without pre-baking. The UL 94V-0 molding compound also withstands peak temperatures up to 260 °C.
Does SMA4F12AH support bidirectional transient suppression?
No, SMA4F12AH is a unidirectional TVS diode, designed for DC circuits with defined polarity such as 12 V automotive power rails. Its electrical specifications - including forward voltage (VF = 3.5 V at 25 A) and cathode-band marking - confirm single-direction conduction. For AC or bipolar signal lines, a bidirectional variant like SMA4F12AY would be required.
What is the maximum clamping voltage of SMA4F12AH under surge conditions?
The SMA4F12AH clamps to a maximum of 19.5 V at 20.5 A peak impulse current (IPPM) under a 10/1000 µs waveform. This value is measured and guaranteed per datasheet specifications, providing a known upper bound for protected circuit voltage during transients - essential for validating margin against downstream IC absolute maximum ratings.
How does the thermal performance of SMA4F12AH compare to standard SMA packages?
SMA4F12AH uses a Thin SMA package with improved thermal metrics: RθJL = 20 °C/W and RθJA = 62 °C/W (on 5 mm × 5 mm Cu pad). This represents a ~15% reduction in junction-to-ambient resistance versus legacy SMA packages, enabling higher sustained power dissipation and more reliable operation in compact, thermally constrained automotive modules.
SMA4F12AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-221AC, SMA Flat Leads
- Series:
- SMA4F
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.4V
- Voltage - Clamping (Max) @ Ipp:
- 19.5V
- Current - Peak Pulse (10/1000µs):
- 20.5A
- 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:
- Thin SMA
SMA4F12AH FAQ
1.How can I place an order for SMA4F12AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA4F12AH 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 SMA4F12AH reliable?
The price and inventory of SMA4F12AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA4F12AH is usually 5 days.
3.What payment methods are accepted for SMA4F12AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA4F12AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA4F12AH?
SMA4F12AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA4F12AH 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 SMA4F12AH?
For technical support, including SMA4F12AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA4F12AH requirements.
6.How does Aetrix verify that SMA4F12AH is sourced from the original manufacturer or authorized distributors?
All SMA4F12AH 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 SMA4F12AH meets industry standards.
7.What is the process for return or replacement of SMA4F12AH?
All SMA4F12AH units undergo pre-shipment inspection (PSI). If there is an issue with SMA4F12AH, 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 SMA4F12AH part is unused and in its original packaging.
Return procedure for SMA4F12AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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