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Taiwan Semiconductor Corporation SMAJ51A
- Part No.:
- SMAJ51A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51A.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,053
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Product details
Overview
SMAJ51A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 51 V working stand-off voltage (VWM), 56.7–62.7 V breakdown voltage (VBR), 82.4 V maximum clamping voltage (VC) at 4.9 A peak impulse current, and 400 W peak pulse power rating with 10/1000 µs waveform - ideal for protecting SMPS outputs and DC/DC converter inputs against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ51A datasheet, SMAJ51A pinout, SMAJ51A application, or SMAJ51A equivalent, key selection criteria include its DO-214AC (SMA) package compatibility with automated placement, sub-1 ps response time, <1 µA reverse leakage above 10 V, UL 94V-0 molding compound, and JESD201 Class 2 whisker resistance - all critical for automotive-grade and industrial power supply designs requiring high-reliability surge immunity.
Technical Context
The SMAJ51A operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve fast transient response (<1.0 ps from 0 V to VBR min) and stable clamping performance under repetitive or single-event surges. Its electrical behavior is defined by strict VBR tolerance (±5% typical for A-suffix parts), low dynamic impedance, and predictable VC–IPPM relationship per IEC 61000-4-5 and ISO 7637-2 compliance testing.
Thermally, it supports operation from –55 °C to +150 °C junction temperature, with steady-state power dissipation of 1 W and peak pulse power derated linearly above 25 °C ambient. The device uses a single-die configuration in DO-214AC package, with cathode band marking for polarity identification and matte tin-plated leads compliant with J-STD-002 solderability standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR @ IT=1 mA | 56.7–62.7 V - Breakdown threshold range ensuring reliable turn-on during overvoltage events |
| VC @ IPPM=4.9 A | 82.4 V - Clamped voltage seen by protected circuit during 10/1000 µs surge, limiting stress on downstream components |
| PPPM (10/1000 µs) | 400 W - Peak surge energy handling capacity, sufficient for ISO 7637-2 Pulse 2b (50 V, 100 ms) and Pulse 3b (±200 V, 150 ns) |
| IR @ VWM | <1 µA - Negligible leakage current at rated stand-off voltage, preserving efficiency in low-power systems |
| TJ max | +150 °C - Enables use in thermally constrained environments such as enclosed power adapters and automotive ECUs |
| Package | DO-214AC (SMA) - Industry-standard SMD outline compatible with JEDEC MS-013, supporting high-volume reflow assembly |
Pinout & Package
DO-214AC (SMA) is a two-terminal surface-mount package with cathode band marking on the body. Terminals are matte tin-plated leads, solderable per J-STD-002, and meet JESD201 Class 2 whisker resistance requirements. Polarity is unidirectional: anode and cathode are designated by the band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side terminal | Connected to protected line (e.g., +VIN rail); conducts during reverse-biased transient events |
| Cathode | Ground/reference side terminal | Connected to system ground or return path; defines clamping reference point and polarity orientation |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR over lifetime and improved reliability vs. epoxy-passivated alternatives in humid or high-bias environments |
| Fast response time <1.0 ps | Enables suppression before sensitive ICs experience damaging voltage overshoot during ESD or load dump events |
| Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b | Validated for automotive power line immunity testing, including load dump (Pulse 5a/b) when used with appropriate series impedance |
| Moisture sensitivity level 1 (J-STD-020) | Eliminates need for dry pack or baking prior to reflow, reducing manufacturing overhead and risk of popcorning |
| Halogen-free & RoHS-compliant | Supports environmental compliance for global markets including EU, China RoHS, and JEITA EG02 |
Applications
| Switching Mode Power Supply (SMPS) | On-board DC/DC Converter |
|---|---|
Use Scenario: Protection of primary-side input rectifier and secondary-side output rectifier against line-induced surges and switching noise. IC Role / Device Role / Timing Role: Unidirectional TVS placed across input bulk capacitor or output filter capacitor to clamp transients before they reach controller ICs or MOSFETs. Use Value: Limits peak voltage to ≤82.4 V during 400 W 10/1000 µs surges, preventing gate oxide damage in PWM controllers and overvoltage failure in synchronous rectifiers. | Use Scenario: Input rail protection for isolated or non-isolated buck/boost converters in motor drives and industrial PLCs. IC Role / Device Role / Timing Role: Standoff-rated TVS connected between VIN and GND to absorb coupled transients from adjacent high-current switching stages. Use Value: With 51 V VWM and 82.4 V VC, it protects 48 V nominal systems while maintaining >10 V margin below typical 60 V absolute maximum ratings of DC/DC controller ICs. |
| Automotive Lighting Module | Industrial Adapter Interface |
Use Scenario: Surge suppression on LED driver input in headlamp or tail lamp modules exposed to battery line disturbances. IC Role / Device Role / Timing Role: Primary-line TVS absorbing load dump pulses (ISO 7637-2 Pulse 5a) when alternator regulation fails. Use Value: Delivers 400 W peak pulse power handling and meets JESD201 Class 2 whisker resistance, ensuring long-term reliability in vibration-prone automotive environments. | Use Scenario: Input-stage protection for universal-input AC/DC adapters powering IoT gateways and edge sensors. IC Role / Device Role / Timing Role: First-line defense against fast-rising surges from shared building wiring or nearby lightning-induced coupling. Use Value: Sub-1 ps response and <1 µA IR at 51 V enable low standby loss and immediate clamping - critical for Energy Star and ERP Tier 2 compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ51A | Same VWM/VBR/VC specs but in DO-214AA (SMB) package - 2.5 mm wider body, higher thermal mass, 600 W PPPM rating | Better suited for higher-energy surges or elevated ambient temperatures due to larger footprint and improved heat dissipation | Select SMBJ51A when PCB layout allows larger pad area and system-level surge testing exceeds 400 W requirements |
| P6SMB51A | Identical electrical specs and DO-214AA package; manufactured by Vishay; same 400 W rating but slightly higher typical IR (≤5 µA) | Drop-in alternative where dual-sourcing or second-source qualification is required for automotive or medical BOMs | Choose P6SMB51A when supply chain diversification or legacy design reuse (e.g., prior Vishay-based platforms) is prioritized |
Compared with SMBJ51A and P6SMB51A, the SMAJ51A offers identical clamping performance in a smaller DO-214AC footprint - enabling tighter board layouts and lower assembly cost - while maintaining full ISO 7637-2 compliance and J-STD-020 Level 1 moisture handling for high-throughput SMT lines.
Availability
SMAJ51A is available at Aetrix Electronics and suitable for switching mode power supplies, automotive lighting modules, and industrial DC/DC converters requiring stable component supply, automotive-grade reliability, and RoHS/halogen-free compliance.
Supply support for SMAJ51A 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, MOSFETs, and power management devices since 1979.
The SMAJ series is part of TSC's high-reliability transient suppression portfolio, engineered specifically for automotive, industrial, and computing applications demanding ISO 7637-2 and IEC 61000-4-5 compliance in compact surface-mount packages.
FAQ
What is the polarity configuration of SMAJ51A?
The SMAJ51A is a unidirectional TVS diode, meaning it functions as a reverse-biased avalanche device with cathode band marking indicating the cathode terminal. It conducts only when the anode is driven negative relative to cathode beyond VBR, making it suitable for DC rail protection where polarity is fixed. This differs from bidirectional variants (e.g., SMAJ51CA), which suppress surges in both directions.
Does SMAJ51A meet automotive surge immunity standards?
Yes, SMAJ51A meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements per manufacturer documentation. Its 400 W peak pulse power rating, fast <1.0 ps response, and specified clamping voltage (82.4 V at 4.9 A) ensure robust protection against common automotive transients - though system-level validation with actual line impedance and coupling paths remains essential for full compliance.
What is the maximum operating temperature for SMAJ51A?
The SMAJ51A has a maximum junction temperature (TJ max) of +150 °C and operates across –55 °C to +150 °C. Its thermal performance is validated up to this limit under steady-state 1 W power dissipation and pulsed 400 W conditions, provided PCB copper area and airflow meet recommended layout guidelines in the TSC DO-214AC thermal derating curves.
How does SMAJ51A differ from SMAJ51 (non-A suffix)?
The "A" suffix in SMAJ51A denotes tighter VBR tolerance: 56.7–62.7 V (±5.5% typical) versus SMAJ51's 56.7–69.3 V (±11%). This results in more consistent clamping onset and lower VC variation across production lots. SMAJ51A also exhibits lower typical IR (<1 µA vs. ≤5 µA), improving efficiency in always-on circuits.
Is SMAJ51A compatible with lead-free reflow processes?
Yes, SMAJ51A is fully compatible with standard lead-free reflow profiles (JEDEC J-STD-020). Its DO-214AC package uses matte tin-plated leads qualified to J-STD-002, and the molding compound meets UL 94V-0 flammability rating. Moisture sensitivity level is rated J-STD-020 Level 1, eliminating bake requirements prior to assembly.
SMAJ51A 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):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 4.9A
- 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)
SMAJ51A FAQ
1.How can I place an order for SMAJ51A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51A 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 SMAJ51A reliable?
The price and inventory of SMAJ51A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51A is usually 5 days.
3.What payment methods are accepted for SMAJ51A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51A?
SMAJ51A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51A 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 SMAJ51A?
For technical support, including SMAJ51A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51A requirements.
6.How does Aetrix verify that SMAJ51A is sourced from the original manufacturer or authorized distributors?
All SMAJ51A 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 SMAJ51A meets industry standards.
7.What is the process for return or replacement of SMAJ51A?
All SMAJ51A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51A, 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 SMAJ51A part is unused and in its original packaging.
Return procedure for SMAJ51A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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