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Taiwan Semiconductor Corporation SMAJ14
- Part No.:
- SMAJ14
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ14.pdf
- Description:
- 400W, 17.4V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:4,893
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Product details
Overview
SMAJ14 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for overvoltage protection in DC power lines and signal paths. It features a 14 V working stand-off voltage (VWM), 15.6–19.1 V breakdown voltage (VBR) at 1 mA test current, and clamps transients to ≤25.8 V at 15.5 A peak impulse current under 10/1000 µs waveform, delivering 400 W peak pulse power.
For engineers reviewing the SMAJ14 datasheet, SMAJ14 pinout, SMAJ14 application, or SMAJ14 equivalent, this device is selected for robust ESD and surge immunity in automotive power supplies, industrial DC/DC converters, and lighting drivers where fast response (<1 ps), low leakage (<1 µA at VWM), and DO-214AC package compatibility are critical.
Technical Context
The SMAJ14 operates as a unidirectional avalanche diode with glass-passivated junction, enabling sub-nanosecond response to voltage transients. Its clamping behavior is defined by a 10/1000 µs double-exponential pulse waveform, and it meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b for automotive load-dump and inductive-switching immunity.
Thermal performance is rated for junction temperatures from –55 °C to +150 °C, with steady-state power dissipation of 1 W and peak forward surge current capability of 40 A (8.3 ms half-sine). Polarity is marked by cathode band; moisture sensitivity level is J-STD-020 Level 1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 14 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR min/max | 15.6 V / 19.1 V at 1 mA - Ensures reliable avalanche initiation across process variation |
| VC @ IPPM | 25.8 V at 15.5 A - Clamped voltage during 10/1000 µs surge, limiting downstream stress |
| PPPM | 400 W - Peak pulse power handling per single non-repetitive event |
| IR @ VWM | <1 µA - Negligible leakage current preserves efficiency in low-power standby circuits |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline with 0.060 g mass and UL 94V-0 molding |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, cathode indicated by band marking; polarity-critical for unidirectional operation; compliant with J-STD-002 solderability and JESD 201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection in unidirectional configuration | Connected to ground or return path; conducts during reverse transient |
| Cathode | High-side connection with polarity mark | Connected to protected line; blocks normal operation, avalanches during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enables stable, repeatable breakdown voltage and long-term reliability under thermal cycling |
| Response time <1.0 ps | Protects sensitive ICs before transient energy couples into system traces |
| ISO 7637-2 compliance | Validated for automotive electronics including load dump (Pulse 2b) and supply interruption (Pulse 3b) |
| RoHS & halogen-free | Meets IEC 61249-2-21 and EU environmental directives for green manufacturing |
Applications
| Automotive Power Supply Protection | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs against load dump and alternator spikes. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and chassis ground to clamp surges above 14 V. Use Value: Limits clamped voltage to 25.8 V, preventing damage to downstream regulators and microcontrollers rated for 30 V absolute max. | Use Scenario: Safeguarding isolated DC/DC converter primary side in factory automation controllers. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing repetitive switching transients from MOSFET turn-off. Use Value: With 1 µA leakage at 14 V, it avoids loading low-quiescent-current bias networks while sustaining 400 W pulses. |
| LED Driver Overvoltage Clamp | USB-C Power Delivery Line Protection |
Use Scenario: Shielding constant-current LED driver ICs from inductive kickback in streetlight ballasts. IC Role / Device Role / Timing Role: Fast-clamping TVS on output rail to suppress flyback voltage from inductor discharge. Use Value: Sub-1 ps response ensures clamping initiates before driver IC's internal FET fails due to VDS overvoltage. | Use Scenario: Adding surge resilience to 5–20 V USB-C PD input stages in portable medical devices. IC Role / Device Role / Timing Role: Unidirectional TVS on VBUS line, referenced to system ground, rated for 14 V nominal operation. Use Value: Meets IEC 61000-4-5 Level 3 (1 kV line-earth) when combined with series impedance, without compromising PD negotiation timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ14A | Narrower VBR range (15.6–17.2 V); tighter tolerance improves consistency in high-volume production | Better suited for designs requiring tighter clamping predictability across temperature and lot variance | Select SMAJ14A when VBR matching and reduced VC variation are prioritized over cost |
| SMBJ14 | Same VWM/VBR specs but in DO-214AA (SMB) package - 2.5 mm wider body, higher thermal mass | Preferred where board space allows larger footprint and higher steady-state power margin is needed | Choose SMBJ14 if PCB layout permits larger pad area and thermal derating headroom is required |
Compared with SMAJ14A, the SMAJ14 offers broader VBR tolerance and lower unit cost; compared with SMBJ14, it provides identical electrical performance in a smaller DO-214AC footprint-critical for dense automotive modules where board area is constrained.
Availability
SMAJ14 is available at Aetrix Electronics and suitable for automotive power supplies, industrial DC/DC converters, and LED lighting systems requiring stable component supply, full traceability, and long-term lifecycle support.
Supply support for SMAJ14 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 management, protection, and interface components.
The SMAJ series is part of TSC's transient voltage suppressor product line, engineered specifically for high-reliability automotive and industrial surge protection with emphasis on ISO 7637-2 compliance, tight thermal derating, and automated assembly readiness.
FAQ
What is the maximum clamping voltage of the SMAJ14 under standard surge conditions?
The SMAJ14 clamps to a maximum of 25.8 V when subjected to a 10/1000 µs waveform with a peak impulse current of 15.5 A. This value is measured per JEDEC standards and represents the upper limit of voltage seen by downstream circuitry during transient events, ensuring compatibility with 30 V-rated ICs and power stages.
Is the SMAJ14 suitable for bidirectional surge protection?
No - the SMAJ14 is a unidirectional TVS diode, intended only for DC line protection with defined polarity. For bidirectional applications such as AC lines or data bus protection, the SMAJ14CA variant (with 'CA' suffix) must be used; the SMAJ14 lacks symmetrical breakdown characteristics and will conduct continuously if reverse-biased beyond its VWM.
What is the thermal derating behavior of the SMAJ14 above 25°C ambient?
The SMAJ14's peak pulse power rating decreases linearly above 25°C ambient per Figure 2 in the datasheet: at 85°C TA, its PPPM is reduced to approximately 280 W; at 125°C, it drops to ~160 W. Derating is essential for sustained surge duty cycles in under-hood or enclosed industrial environments.
Does the SMAJ14 meet automotive qualification standards?
Yes - the SMAJ14 meets ISO 7637-2 Pulse 1 (inductive load disconnect), Pulse 2a (sudden load removal), Pulse 2b (supply interruption), Pulse 3a/3b (capacitive coupling and ignition noise), and is AEC-Q200 stress-tested per TSC's internal qualification protocol for passive components.
What is the marking code for the SMAJ14 on the device body?
The SMAJ14 is marked with code 'BH' on the cathode-banded surface of the DO-214AC package. This two-character laser marking aligns with Taiwan Semiconductor's standardized coding scheme and is visible under 20× magnification; the cathode band denotes the terminal connected to the protected line.
SMAJ14 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 14V
- Voltage - Breakdown (Min):
- 15.6V
- Voltage - Clamping (Max) @ Ipp:
- 25.8V
- Current - Peak Pulse (10/1000µs):
- 15.5A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ14 FAQ
1.How can I place an order for SMAJ14 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ14 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 SMAJ14 reliable?
The price and inventory of SMAJ14 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ14 is usually 5 days.
3.What payment methods are accepted for SMAJ14?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ14 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ14?
SMAJ14 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ14 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 SMAJ14?
For technical support, including SMAJ14 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ14 requirements.
6.How does Aetrix verify that SMAJ14 is sourced from the original manufacturer or authorized distributors?
All SMAJ14 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 SMAJ14 meets industry standards.
7.What is the process for return or replacement of SMAJ14?
All SMAJ14 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ14, 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 SMAJ14 part is unused and in its original packaging.
Return procedure for SMAJ14:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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