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Taiwan Semiconductor Corporation SMAJ12CAH
- Part No.:
- SMAJ12CAH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12CAH.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,205
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Product details
Overview
SMAJ12CAH from Taiwan Semiconductor is a bidirectional 12 V transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, rated for 400 W peak pulse power (10/1000 µs), 22.0 V maximum clamping voltage at 18.2 A peak impulse current, and AEC-Q101 qualified for automotive-grade surge protection in DC/DC converters and SMPS input stages.
For engineers reviewing the SMAJ12CAH datasheet, SMAJ12CAH pinout, SMAJ12CAH application, or SMAJ12CAH equivalent, key selection criteria include bidirectional standoff voltage (12 V), clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, junction temperature range (–55 °C to +150 °C), and RoHS/halogen-free compliance for automotive electronics design.
Technical Context
SMAJ12CAH is a glass-passivated, single-die, bidirectional TVS diode optimized for fast transient suppression in automotive and industrial power rails. Its breakdown voltage is specified at 13.3–14.7 V (IT = 1 mA), with <1.0 ps response time from 0 V to VBR min and typical IR <1 µA at VWM.
The device meets ISO 7637-2 immunity requirements for vehicle electrical systems and supports unidirectional/bidirectional configurations via CH/CAH suffixes. It operates across –55 °C to +150 °C junction temperature and delivers 400 W peak pulse power up to 78 V, derating linearly above 25 °C ambient per Fig.2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin for 12 V automotive systems. |
| VBR min/max | 13.3 / 14.7 V @ IT = 1 mA - Confirmed breakdown threshold ensures reliable turn-on during transients without premature conduction. |
| VC @ IPPM | 22.0 V @ 18.2 A - Clamping voltage limits downstream IC stress during 10/1000 µs surges (e.g., load dump, inductive switching). |
| PPPM | 400 W (10/1000 µs) - Peak surge energy handling capacity validated per IEC 61000-4-5 and ISO 7637-2 test waveforms. |
| IR @ VWM | <1 µA - Ultra-low leakage preserves battery life and avoids false triggering in always-on circuits. |
| TJ max | +150 °C - Enables placement near hot components (e.g., MOSFETs, inductors) in compact power modules. |
| Package | DO-214AC (SMA) - Surface-mount footprint compatible with automated assembly; 0.060 g weight supports lightweight board design. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band (bidirectional operation uses symmetrical terminals; no anode/cathode distinction required).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (Bidirectional) | Transient current path | Both terminals conduct equally during positive/negative surges; no orientation dependency on PCB layout. |
| Case | Thermal and mechanical interface | Plastic body provides UL 94V-0 flammability rating and JESD201 Class 2 whisker resistance; no thermal pad required. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive underhood applications including temperature cycling, humidity bias, and mechanical shock per JESD47. |
| Glass-passivated junction | Enhances long-term reliability and stability of VBR and VC under repeated surge stress and high-humidity environments. |
| ISO 7637-2 compliance | Meets Pulse 1 (inductive load disconnect), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) immunity requirements. |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow; supports standard SMT processes without floor-life constraints. |
| RoHS & halogen-free | Complies with IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally constrained supply chains. |
Applications
| Automotive Body Control Module (BCM) | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protects microcontroller I/O and CAN transceiver power rails from load dump and jump-start surges in 12 V vehicle networks. IC Role / Device Role / Timing Role: Bidirectional clamping element placed directly at connector entry point to shunt transients before reaching sensitive logic. Use Value: Limits voltage excursion to ≤22.0 V during 10/1000 µs pulses, preventing latch-up or permanent damage to 3.3 V/5 V peripherals. |
Use Scenario: Shields primary-side controller ICs and gate drivers in offline AC/DC adapters against line-induced surges and EFT events. IC Role / Device Role / Timing Role: Fast-response overvoltage clamp on bulk capacitor rail, activated within <1.0 ps to suppress spikes before regulation loop reacts. Use Value: Maintains stable 12 V output under 400 W transient stress, enabling use without oversized input capacitors or secondary crowbar circuits. |
| LED Driver Power Input | On-board DC/DC Converter Protection |
Use Scenario: Safeguards constant-current LED driver ICs in automotive lighting modules from alternator ripple and ignition noise. IC Role / Device Role / Timing Role: Standoff-rated TVS placed between input filter and buck controller to absorb repetitive low-energy transients. Use Value: Delivers <1 µA leakage at 12 V, minimizing standby power loss while clamping to 22.0 V to preserve driver FET SOA. |
Use Scenario: Secures 5 V or 3.3 V point-of-load regulators in ADAS ECUs against back-EMF from nearby solenoid actuators. IC Role / Device Role / Timing Role: Localized transient suppressor mounted adjacent to DC/DC converter input pins to minimize inductive loop area. Use Value: Enables robust operation across –40 °C to +125 °C ambient with no derating below 400 W peak power up to 78 V working voltage. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12AHE3/5BT | Same VWM (12 V), identical VBR (13.3–14.7 V), but Vishay variant uses different molding compound and JEDEC-compliant tape/reel packaging. | No functional difference in clamping or surge rating; differs only in traceability documentation and moisture sensitivity labeling (MSL 1 vs MSL 1 per J-STD-020). | Select SMAJ12AHE3/5BT when dual-sourcing or requiring Vishay's extended lifecycle reporting for Tier-1 automotive programs. |
| P6SMB12CA | Same DO-214AA (SMB) package footprint but lower 600 W rating; VWM = 12 V, VC = 19.9 V @ 20.1 A - tighter clamping but higher cost and larger size. | Better clamping ratio (19.9 V/12 V = 1.66 vs SMAJ12CAH's 22.0 V/12 V = 1.83), yet requires PCB redesign due to SMB vs SMA footprint mismatch. | Choose P6SMB12CA only if clamping voltage margin is critical and board space allows SMB package; not drop-in compatible. |
Compared with SMAJ12CAH, SMAJ12AHE3/5BT offers identical electrical performance with alternate supply-chain traceability, while P6SMB12CA improves clamping by 2.1 V but demands PCB layout revision and increases BOM cost by ~18%.
Availability
SMAJ12CAH is available at Aetrix Electronics and suitable for automotive body control modules, industrial SMPS designs, and LED driver power inputs requiring stable component supply with AEC-Q101 validation and ISO 7637-2 compliance.
Supply support for SMAJ12CAH 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 power MOSFETs for automotive and industrial markets.
SMAJ series TVS diodes were developed specifically for AEC-Q101-compliant transient protection in 12 V/24 V vehicle electrical architectures, emphasizing fast response, low leakage, and robust surge endurance under thermal cycling.
FAQ
What is the clamping voltage of SMAJ12CAH under a 10/1000 µs surge?
The SMAJ12CAH clamps to a maximum of 22.0 V when subjected to its rated peak impulse current of 18.2 A using the standardized 10/1000 µs waveform. This value is measured per IEC 61000-4-5 and is guaranteed across the full operating temperature range of –55 °C to +150 °C junction temperature.
Is SMAJ12CAH suitable for bidirectional automotive data lines like LIN or CAN?
No - SMAJ12CAH is designed for power rail protection, not signal line clamping. Its capacitance (not specified in the datasheet) and clamping dynamics make it unsuitable for high-speed data buses. For LIN/CAN, dedicated low-capacitance TVS arrays such as TPD2E001 or SP1003 are recommended instead of SMAJ12CAH.
Does SMAJ12CAH require derating above 25 °C ambient temperature?
Yes - SMAJ12CAH's peak pulse power must be linearly derated above TA = 25 °C per Figure 2 in the datasheet. At 85 °C ambient, its 400 W rating reduces to approximately 260 W, and at 125 °C, it falls to ~140 W. Thermal design must account for this to maintain surge immunity.
What does the "CAH" suffix indicate in SMAJ12CAH?
The "CAH" suffix denotes a bidirectional configuration with 12 V working standoff voltage. "C" indicates bidirectional capability, "A" specifies the tighter VBR tolerance (13.3–14.7 V vs 13.3–16.3 V for "H"), and "H" identifies the high-reliability, AEC-Q101-qualified variant per Taiwan Semiconductor's ordering code convention.
Can SMAJ12CAH replace SMAJ12AH in an existing design?
Yes - SMAJ12CAH is functionally equivalent to SMAJ12AH in all electrical parameters (VWM = 12 V, VBR = 13.3–14.7 V, VC = 22.0 V), with identical DO-214AC (SMA) package and pinout. The "C" prefix confirms bidirectional operation, matching SMAJ12AH's behavior; no layout or firmware changes are needed when substituting SMAJ12CAH.
SMAJ12CAH 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:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 20.1A
- 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)
SMAJ12CAH FAQ
1.How can I place an order for SMAJ12CAH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12CAH 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 SMAJ12CAH reliable?
The price and inventory of SMAJ12CAH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12CAH is usually 5 days.
3.What payment methods are accepted for SMAJ12CAH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12CAH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12CAH?
SMAJ12CAH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12CAH 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 SMAJ12CAH?
For technical support, including SMAJ12CAH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12CAH requirements.
6.How does Aetrix verify that SMAJ12CAH is sourced from the original manufacturer or authorized distributors?
All SMAJ12CAH 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 SMAJ12CAH meets industry standards.
7.What is the process for return or replacement of SMAJ12CAH?
All SMAJ12CAH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12CAH, 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 SMAJ12CAH part is unused and in its original packaging.
Return procedure for SMAJ12CAH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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