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Vishay General Semiconductor - Diodes Division SMAJ12CAHM3P/H
- Part No.:
- SMAJ12CAHM3P/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ12CAHM3P/H.pdf
- Description:
- TVS DIODE 12VWM 19.9VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,301
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Product details
Overview
SMAJ12CAHM3P/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping ESD and surge transients on signal/power lines. It features 12 V stand-off voltage (VWM), 13.3–14.7 V breakdown voltage (VBR) at 1 mA, 19.9 V maximum clamping voltage (VC) at 20.1 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform), used to protect MOSFET gates, sensor interfaces, and automotive control modules.
For engineers reviewing the SMAJ12CAHM3P/H datasheet, SMAJ12CAHM3P/H pinout, SMAJ12CAHM3P/H application, or SMAJ12CAHM3P/H equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification status, thermal resistance (RθJA = 120 °C/W), and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This device operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (>1 MΩ leakage at VWM), but switches to low-impedance conduction within <1 ns when transient voltage exceeds VBR. Its bidirectional symmetry enables protection of AC-coupled or differential signal paths without polarity constraints.
The SMAJ12CAHM3P/H uses a glass-passivated silicon junction, rated for -55 °C to +150 °C operating junction temperature, with 3.3 W steady-state power dissipation and 40 A non-repetitive forward surge current (8.3 ms half-sine). It meets J-STD-020 MSL Level 1 and JESD201 Class 2 whisker resistance requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 12 V - Maximum continuous reverse working voltage before clamping begins; defines safe operating margin for 12 V rail protection. |
| VBR min/max | 13.3 V / 14.7 V at 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on before damage to downstream ICs. |
| VC @ IPPM | 19.9 V at 20.1 A - Clamped voltage during 10/1000 μs surge; limits stress on protected circuitry to safe levels. |
| PPPM | 400 W (≤78 V), 300 W (>78 V) - Peak surge energy handling per JEDEC standard; supports IEC 61000-4-5 Level 4 compliance. |
| ID @ VWM | 1.0 μA - Reverse leakage at stand-off voltage; negligible power loss and signal distortion in standby. |
| TJ max | +150 °C - Maximum junction temperature; enables use in under-hood automotive environments and industrial enclosures. |
| RθJA | 120 °C/W - Thermal resistance junction-to-ambient on standard PCB pad; informs heatsinking needs for sustained surge duty. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, halogen-free, RoHS-compliant, AEC-Q101 qualified (HM3 suffix). Dimensions: 4.50 mm × 2.79 mm × 2.29 mm (L × W × H); cathode band absent (bidirectional).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (positive polarity) | One terminal of symmetrical junction; conducts during positive overvoltage events on either side of reference. |
| Cathode | Transient current entry (negative polarity) | Second terminal of symmetrical junction; conducts during negative overvoltage events - functionally identical to Anode in bidirectional mode. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Identical VBR and VC performance in both polarities - eliminates need for polarity-aware layout in AC or differential lines. |
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock - suitable for engine control and ADAS sensors. |
| 400 W peak pulse power | Withstands 10/1000 μs surges up to 20.1 A - meets IEC 61000-4-5 surge immunity requirements for industrial and telecom equipment. |
| Low clamping ratio (VC/VBR ≈ 1.42) | 19.9 V clamping at 14.7 V max VBR - tight voltage margin preserves headroom for 12 V logic and analog circuits. |
| MSL Level 1 rating | Reflow-compatible up to 260 °C peak - supports standard lead-free assembly without moisture sensitivity concerns. |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting CAN/LIN bus transceivers and analog sensor inputs (e.g., pressure, temperature) from load dump and ESD in vehicle ECUs. IC Role / Device Role / Timing Role: Shunt TVS diode placed directly at connector interface to clamp transients before reaching transceiver IC. Use Value: Prevents latch-up or gate oxide damage in 12 V automotive systems by limiting surge voltage to ≤19.9 V during 400 W events. |
Use Scenario: Safeguarding 24 V digital input modules in programmable logic controllers against field-wiring induced surges and relay coil flyback. IC Role / Device Role / Timing Role: Bidirectional voltage clamp across input terminals to absorb ±1 kV/500 A transients per IEC 61000-4-5. Use Value: Enables robust operation in factory environments where wiring errors or inductive switching cause repetitive 10/1000 μs surges. |
| Consumer USB Port ESD Protection | Telecom Line Interface Protection |
Use Scenario: Shielding USB 2.0 data lines (D+/D−) and VBUS in set-top boxes and smart displays from human-body-model (HBM) ESD events. IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS placed adjacent to connector to divert >8 kV contact discharge. Use Value: Maintains signal integrity with <1 pF junction capacitance while meeting IEC 61000-4-2 Level 4 (±15 kV air, ±8 kV contact). |
Use Scenario: Protecting Ethernet PHY or RS-485 transceivers in network edge devices from lightning-induced surges on twisted-pair cabling. IC Role / Device Role / Timing Role: Primary surge suppression stage before secondary protection (e.g., GDT or polymer PTC). Use Value: Absorbs up to 400 W of coupled lightning energy while holding clamping voltage below transceiver absolute maximum ratings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12CAHE3_A/H | Same electrical specs and AEC-Q101 qualification, but RoHS-compliant without halogen-free packaging (E3 vs HM3). | Preferred for commercial/industrial designs where halogen-free mandate does not apply; slightly lower cost. | Select when halogen-free requirement is absent and cost optimization is prioritized over environmental compliance tier. |
| SMBJ12CAHM3 | Higher 600 W PPPM rating, same VWM/VBR/VC, but larger SMB (DO-214AA) package (4.57 mm × 3.94 mm). | Better thermal performance (RθJA = 85 °C/W) and surge margin; requires PCB area increase and re-layout. | Choose when system-level surge testing exceeds 400 W or long-term reliability under repeated transients demands higher energy margin. |
Compared with SMAJ12CAHM3P/H, SMAJ12CAHE3_A/H offers identical protection performance with standard RoHS compliance, while SMBJ12CAHM3 provides 50 % higher surge power handling at the cost of larger footprint and altered thermal design - enabling trade-offs between board space, cost, and ruggedness.
Availability
SMAJ12CAHM3P/H is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC I/O modules, consumer USB port protection, and telecom line interface circuits requiring stable component supply with AEC-Q101 assurance and halogen-free compliance.
Supply support for SMAJ12CAHM3P/H 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in diodes, rectifiers, TVS, MOSFETs, and optoelectronics with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for high-energy transient suppression in space-constrained, high-reliability applications - particularly automotive, industrial, and communications systems where fast response, low clamping, and qualification rigor are mandatory.
FAQ
What is the clamping voltage of SMAJ12CAHM3P/H at its rated peak pulse current?
The SMAJ12CAHM3P/H has a maximum clamping voltage (VC) of 19.9 V at its specified peak pulse current (IPPM) of 20.1 A, measured using the standardized 10/1000 μs waveform. This value is guaranteed across the full operating temperature range and confirms the device's ability to limit transient overvoltage to a safe level for 12 V systems. The SMAJ12CAHM3P/H datasheet specifies this parameter under "Electrical Characteristics" with test conditions fully aligned to JEDEC standards.
Is SMAJ12CAHM3P/H qualified for automotive applications?
Yes, SMAJ12CAHM3P/H is AEC-Q101 qualified, as indicated by the "HM3" suffix and confirmed in Vishay's ordering information and thermal characteristics notes. This qualification covers stress tests including temperature cycling, high-temperature operating life, and unbiased highly accelerated stress testing - validating its suitability for under-hood and chassis-mounted automotive electronics. The SMAJ12CAHM3P/H meets the reliability requirements for engine control units, body control modules, and ADAS sensor interfaces.
How does the bidirectional configuration of SMAJ12CAHM3P/H affect its circuit implementation?
The bidirectional configuration of SMAJ12CAHM3P/H means it functions identically for positive and negative transients, with no polarity marking on the SMA (DO-214AC) package. This allows placement across any two nodes requiring symmetric surge suppression - such as differential data lines (RS-485, CAN), AC-coupled audio paths, or ungrounded power rails - without orientation constraints. Unlike unidirectional variants, SMAJ12CAHM3P/H eliminates risk of incorrect installation and simplifies layout for balanced protection schemes.
What is the thermal resistance of SMAJ12CAHM3P/H, and how does it impact PCB layout?
The SMAJ12CAHM3P/H has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the minimum recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value directly determines allowable power dissipation during repetitive surges: exceeding thermal limits risks parametric shift or failure. To maintain reliability, designers must ensure adequate copper area and avoid excessive trace length or isolation - the SMAJ12CAHM3P/H thermal model assumes direct pad connection without thermal vias unless explicitly derated.
Does SMAJ12CAHM3P/H meet industry surge immunity standards like IEC 61000-4-5?
Yes, SMAJ12CAHM3P/H supports compliance with IEC 61000-4-5 Level 4 (4 kV line-to-earth, 2 kV line-to-line) due to its 400 W peak pulse power rating (10/1000 μs waveform) and 19.9 V clamping voltage. When implemented with proper PCB layout - including short traces, ground plane coupling, and coordination with upstream filtering - the SMAJ12CAHM3P/H forms the primary clamping stage in multi-stage protection architectures required for industrial and automotive equipment certification.
SMAJ12CAHM3P/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- 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:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ12CAHM3P/H FAQ
1.How can I place an order for SMAJ12CAHM3P/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ12CAHM3P/H 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 SMAJ12CAHM3P/H reliable?
The price and inventory of SMAJ12CAHM3P/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ12CAHM3P/H is usually 5 days.
3.What payment methods are accepted for SMAJ12CAHM3P/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ12CAHM3P/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ12CAHM3P/H?
SMAJ12CAHM3P/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ12CAHM3P/H 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 SMAJ12CAHM3P/H?
For technical support, including SMAJ12CAHM3P/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ12CAHM3P/H requirements.
6.How does Aetrix verify that SMAJ12CAHM3P/H is sourced from the original manufacturer or authorized distributors?
All SMAJ12CAHM3P/H 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 SMAJ12CAHM3P/H meets industry standards.
7.What is the process for return or replacement of SMAJ12CAHM3P/H?
All SMAJ12CAHM3P/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ12CAHM3P/H, 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 SMAJ12CAHM3P/H part is unused and in its original packaging.
Return procedure for SMAJ12CAHM3P/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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