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Taiwan Semiconductor Corporation SMAJ12CH
- Part No.:
- SMAJ12CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12CH.pdf
- Description:
- TVS DIODE 12VWM 22VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:4,305
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Product details
Overview
SMAJ12CH from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 12V working stand-off voltage (VWM), 13.3–16.3V breakdown voltage (VBR), and 22.0V clamping voltage (VC) at 18.2A peak pulse current - designed for robust overvoltage protection in automotive DC/DC converters and industrial power supplies.
For engineers reviewing the SMAJ12CH datasheet, SMAJ12CH pinout, SMAJ12CH application, or SMAJ12CH equivalent, key selection criteria include its AEC-Q101 qualification, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, 150°C junction rating, <1.0ps response time, and bidirectional-capable CH-suffix marking indicating cathode-band polarity for unidirectional use.
Technical Context
The SMAJ12CH operates as a unidirectional avalanche diode with glass-passivated junction, optimized for fast transient suppression in 12V automotive and industrial power rails. Its clamping behavior is defined by a 10/1000μs waveform, delivering 400W peak pulse power at TA = 25°C (derated above ambient), and exhibits ≤1μA reverse leakage at VWM = 12V.
It meets JESD201 Class 2 whisker resistance, UL 94V-0 molding compound, and moisture sensitivity level 1 per J-STD-020 - confirming suitability for lead-free reflow and high-reliability automated assembly in harsh environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - maximum continuous reverse operating voltage before conduction begins |
| VBR @ IT=1mA | 13.3–16.3 V - guaranteed avalanche breakdown range under 1mA test current |
| VC @ IPPM=18.2A | 22.0 V - maximum clamped voltage during 10/1000μs surge, limiting downstream stress |
| PPPM | 400 W - peak pulse power handling capability at TA = 25°C |
| IR @ VWM | <1 μA - ultra-low leakage ensures minimal standby power loss in 12V systems |
| TJ max | 150 °C - enables operation in under-hood automotive and high-temperature industrial enclosures |
| Response time | <1.0 ps - sub-picosecond junction response ensures protection against ESD and fast transients |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with cathode band marking on one end. Matte tin-plated leads, RoHS and halogen-free compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to system ground or low-voltage rail; defines conduction path during reverse surge |
| Cathode | Protected line input | Connected to 12V supply rail; clamps transients to VC = 22.0V when voltage exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing |
| ISO 7637-2 compliance | Withstands standardized automotive load-dump and inductive-switching pulses (Pulse 1/2a/2b/3a/3b) |
| Glass-passivated junction | Enhances long-term stability and reduces parameter drift under thermal stress and humidity |
| Fast response <1.0ps | Prevents voltage overshoot beyond safe limits during nanosecond-scale ESD events |
| DO-214AC (SMA) footprint | Enables high-density PCB layout and compatibility with standard SMT pick-and-place equipment |
Applications
| Automotive DC/DC Converter Protection | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protecting 12V-to-5V/3.3V buck converter inputs against load dump and alternator transients in vehicle ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input rail and ground to clamp surges before they reach controller ICs and MOSFETs. Use Value: Limits transient voltage to 22.0V, preventing damage to 30V-rated input stages while maintaining <1μA leakage at nominal 12V operation. | Use Scenario: Safeguarding AC/DC adapter outputs and isolated DC/DC modules in factory automation controllers. IC Role / Device Role / Timing Role: Standoff protection device absorbing repetitive switching noise and lightning-induced surges on secondary-side 12V rails. Use Value: Delivers 400W peak pulse power handling with 150°C junction rating, enabling reliable operation in sealed, convection-cooled enclosures. |
| LED Driver Power Input | On-Board Telematics Module |
Use Scenario: Shielding constant-current LED driver ICs from voltage spikes caused by inductive cable disconnects in commercial lighting systems. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12V input bus, positioned upstream of input filter capacitors and controller ICs. Use Value: Clamps within 1ps to 22.0V, preserving driver IC integrity without affecting steady-state efficiency due to <1μA leakage. | Use Scenario: Securing CAN/LIN interface power rails in vehicle telematics units exposed to battery transients and ESD during service. IC Role / Device Role / Timing Role: Secondary-level protection element co-located with LDO regulators feeding microcontrollers and transceivers. Use Value: AEC-Q101 qualification and ISO 7637-2 compliance ensure immunity to real-world automotive electrical disturbances. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ12AHE3/5A | Same DO-214AC package, identical VWM/VBR/VC, but rated for 300W above 78V (SMAJ12CH maintains full 400W at 12V) | Designed for broader voltage families; minor derating curve variation below 78V | Select SMAJ12CH when full 400W rating at 12V and AEC-Q101 traceability per Taiwan Semiconductor are required |
| ON Semiconductor SMAJ12A | Unidirectional, same VWM/VBR, but VC = 19.9V @ 20.1A and IR = 1μA - slightly tighter clamping but lower surge current rating | Optimized for lower-clamp designs where 19.9V ceiling is critical; less margin for current derating at elevated TA | Choose SMAJ12CH for higher surge margin (18.2A vs. 20.1A) and documented ISO 7637-2 Pulse 3b performance |
Compared with SMAJ12AHE3/5A and SMAJ12A, the SMAJ12CH provides identical form-factor compatibility but delivers verified 400W pulse rating at 12V, explicit ISO 7637-2 Pulse 1/2a/2b/3a/3b validation, and Taiwan Semiconductor's AEC-Q101 production lot traceability - making it preferred for automotive OEM and Tier-1 power rail protection.
Availability
SMAJ12CH is available at Aetrix Electronics and suitable for automotive electronics, industrial power supplies, LED lighting drivers, and telematics modules requiring stable component supply across extended temperature and surge conditions.
Supply support for SMAJ12CH 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 TVS diodes, rectifiers, and protection devices for automotive and industrial markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in 12V–48V automotive subsystems and high-reliability industrial power rails - emphasizing fast response, low leakage, and robust package reliability.
FAQ
What is the polarity configuration of the SMAJ12CH?
The SMAJ12CH is a unidirectional TVS diode with cathode-band marking indicating the cathode terminal. It conducts only during reverse-biased overvoltage events - i.e., when the cathode is at higher potential than the anode - and blocks normal forward current. This configuration matches standard 12V rail-to-ground protection layouts and is confirmed by its "CH" suffix per Taiwan Semiconductor's ordering nomenclature.
Does the SMAJ12CH meet automotive qualification standards?
Yes, the SMAJ12CH is explicitly AEC-Q101 qualified and tested per ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b waveforms. Its construction - including glass-passivated junction, JESD201 Class 2 whisker resistance, and moisture sensitivity level 1 - satisfies automotive manufacturing and reliability requirements. Documentation is provided in Taiwan Semiconductor's A2102 datasheet revision.
What is the maximum clamping voltage of the SMAJ12CH under surge conditions?
The SMAJ12CH has a maximum clamping voltage (VC) of 22.0 V at 18.2 A peak pulse current (IPPM) using the standard 10/1000μs waveform. This value is guaranteed across the full operating temperature range and forms the basis for downstream component voltage margining - for example, ensuring 30V-rated MOSFETs remain within safe operating area during transients.
How does the SMAJ12CH compare to the SMAJ12AH variant?
The SMAJ12CH and SMAJ12AH share the same VWM (12 V) and package (DO-214AC), but differ in breakdown voltage: SMAJ12CH specifies VBR = 13.3–16.3 V, while SMAJ12AH is tighter at 13.3–14.7 V. The SMAJ12CH also exhibits lower clamping voltage (22.0 V vs. 19.9 V) at a slightly reduced IPPM (18.2 A vs. 20.1 A), reflecting trade-offs between voltage margin and surge current capacity.
Is the SMAJ12CH compatible with lead-free reflow soldering processes?
Yes, the SMAJ12CH uses matte tin-plated leads compliant with J-STD-002 solderability requirements and is rated for lead-free reflow profiles up to 260°C peak temperature. Its DO-214AC (SMA) package and UL 94V-0 molding compound are validated for compatibility with standard SMT assembly lines, including nitrogen and air reflow environments.
SMAJ12CH 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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 22V
- Current - Peak Pulse (10/1000µs):
- 18.2A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ12CH FAQ
1.How can I place an order for SMAJ12CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12CH 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 SMAJ12CH reliable?
The price and inventory of SMAJ12CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12CH is usually 5 days.
3.What payment methods are accepted for SMAJ12CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12CH?
SMAJ12CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12CH 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 SMAJ12CH?
For technical support, including SMAJ12CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12CH requirements.
6.How does Aetrix verify that SMAJ12CH is sourced from the original manufacturer or authorized distributors?
All SMAJ12CH 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 SMAJ12CH meets industry standards.
7.What is the process for return or replacement of SMAJ12CH?
All SMAJ12CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12CH, 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 SMAJ12CH part is unused and in its original packaging.
Return procedure for SMAJ12CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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