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Vishay General Semiconductor - Diodes Division SMAJ51A-M3/5A
- Part No.:
- SMAJ51A-M3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51A-M3/5A.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMAJ51A-M3/5A from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for primary overvoltage protection of DC power rails and signal lines. It features a 51 V standoff voltage (VWM), 56.7–62.7 V breakdown range at 1 mA, clamps transients to ≤82.4 V at 4.9 A peak pulse current, and delivers 400 W peak pulse power (10/1000 μs waveform). It is widely deployed in automotive body control modules to safeguard microcontroller I/O and CAN transceiver power inputs against load dump and inductive switching surges.
For engineers reviewing the SMAJ51A-M3/5A datasheet, SMAJ51A-M3/5A pinout, SMAJ51A-M3/5A application, or SMAJ51A-M3/5A equivalent, key selection criteria include its 51 V working voltage compatibility with 48 V automotive systems, low 0.05 μA leakage at VWM, halogen-free RoHS-compliant M3 packaging, and AEC-Q101 qualification readiness via HM3 variants.
Technical Context
This TVS diode operates as a clamping device in parallel with protected circuitry, entering avalanche conduction when transient voltage exceeds its breakdown threshold. Its glass-passivated junction ensures stable VBR tolerance (±5%) and low dynamic impedance (<1 Ω typical), enabling rapid energy diversion away from sensitive components.
The SMAJ51A-M3/5A is rated for 40 A non-repetitive forward surge current (8.3 ms half-sine), supports operating junction temperatures from –55 °C to +150 °C, and exhibits a positive temperature coefficient of VBR (+0.104 %/°C), ensuring predictable voltage drift across thermal conditions without thermal runaway risk.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 51 V - Maximum continuous DC or RMS voltage the device blocks without clamping; matches 48 V system nominal rails with 6% margin. |
| VBR (Breakdown Voltage) | 56.7–62.7 V at 1 mA - Tight 10% tolerance band ensures consistent turn-on behavior across production lots. |
| VC (Clamping Voltage) | ≤82.4 V at 4.9 A (10/1000 μs) - Limits downstream voltage stress to safe levels for 5 V/3.3 V logic interfaces. |
| IPPM (Peak Pulse Current) | 4.9 A - Sustains single-event transients up to ISO 7637-2 Pulse 1/2a/5a severity levels in automotive environments. |
| PPPM (Peak Pulse Power) | 400 W - Handles high-energy surges on 12 V/24 V/48 V supply lines with standard PCB copper pad layout (0.2" × 0.2"). |
| ID (Max Reverse Leakage) | 1.0 μA at 51 V - Negligible standby current draw; avoids battery drain in always-on vehicle subsystems. |
| TJmax | +150 °C - Enables placement near heat-generating components (e.g., power MOSFETs, DC-DC converters) without derating. |
Pinout & Package
Package: SMA (DO-214AC) - Surface-mount plastic package with matte tin-plated leads, MSL Level 1 (260 °C reflow compatible), UL 94 V-0 rated molding compound, and cathode band marking for polarity identification.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference node | Connected to ground or common return path; forms current path during reverse-biased clamping events. |
| Cathode | Protected line input | Connected to the line being protected (e.g., 48 V rail); avalanche conduction initiates here when VIN > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Supports robust protection against ISO 16750-2 load dump and ISO 7637-2 Pulse 5a transients in 48 V automotive architectures. |
| Halogen-free, RoHS-compliant M3 suffix | Meets automotive environmental compliance requirements (e.g., JESD201 Class 2 whisker resistance) without compromising thermal performance. |
| Low incremental surge resistance | Ensures minimal voltage overshoot during fast-rising transients (<1 ns response time), critical for protecting high-speed interface ICs. |
| 150 °C maximum junction temperature | Enables operation in under-hood ECUs and ADAS domain controllers where ambient temperatures exceed 105 °C. |
| MSL Level 1 moisture sensitivity | Allows standard SMT reflow without dry-packaging or baking, reducing manufacturing cost and handling complexity. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Protection |
|---|---|
|
Use Scenario: Protecting 48 V power inputs to microcontrollers and LIN transceivers against alternator load dump and relay coil flyback. IC Role / Device Role / Timing Role: Unidirectional clamping TVS placed directly at power entry point, shunting surge energy to chassis ground before it reaches LDO regulators. Use Value: Prevents latch-up and permanent damage to 3.3 V MCU cores by limiting input rail excursion to ≤82.4 V during 100 V/500 ms load dump events. |
Use Scenario: Safeguarding 24 V digital input channels on programmable logic controllers exposed to field wiring inductive kick and ESD. IC Role / Device Role / Timing Role: Standoff-rated TVS mounted in series with optocoupler input, absorbing repetitive 400 W transients without degradation. Use Value: Extends mean time between failures (MTBF) of input stage by eliminating false triggering and LED driver overstress during factory floor switching noise. |
| Telecom Power Supply Front-End | Consumer Appliance Motor Drive Board |
|
Use Scenario: Clamping voltage spikes on -48 V telecom rectifier outputs caused by hot-swap insertion and backup battery switchover. IC Role / Device Role / Timing Role: Primary overvoltage clamp on DC distribution bus, coordinated with secondary crowbar circuits for layered protection. Use Value: Maintains uninterrupted operation of line cards during redundant power source transitions by holding bus voltage within ±10% of nominal. |
Use Scenario: Suppressing commutation spikes from brushed DC motors in smart home vacuum cleaners and robotic mowers. IC Role / Device Role / Timing Role: Low-leakage TVS across motor terminals, activated only during brush arcing events (>60 V), minimizing standby power loss. Use Value: Eliminates electromagnetic interference (EMI) that causes Wi-Fi disconnections and touch-panel resets during motor startup/stall. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51A-E3/5A | Same electrical specs; RoHS-compliant but contains brominated flame retardants (non-halogen-free). | Approved for commercial-grade industrial equipment where halogen-free mandate does not apply. | Select when cost sensitivity outweighs halogen-free requirement and AEC-Q101 is not needed. |
| SMAJ51AHM3_A/I | Identical electrical specs; includes AEC-Q101 qualification and 13" tape/reel packaging (7500 pcs). | Required for automotive OEM Tier 1 BOMs and production programs demanding full automotive qualification traceability. | Choose for automotive production releases needing certified reliability data, PPAP documentation, and extended temperature validation. |
Compared with SMAJ51A-M3/5A, the E3 variant offers identical clamping performance at lower cost for non-automotive use, while the HM3_A/I version adds formal AEC-Q101 validation and higher-volume packaging-enabling direct substitution in qualified automotive designs without requalification.
Availability
SMAJ51A-M3/5A is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, telecom power systems, and consumer appliance designs requiring stable component supply, halogen-free compliance, and rapid fulfillment of medium-volume production runs.
Supply support for SMAJ51A-M3/5A 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 high-reliability diodes, MOSFETs, and passive components for automotive, industrial, and computing markets.
The SMAJ series is engineered specifically for board-level transient suppression in harsh environments, emphasizing robust clamping, low leakage, and automotive-grade manufacturability in compact surface-mount packages.
FAQ
What is the maximum clamping voltage of the SMAJ51A-M3/5A under standard test conditions?
The SMAJ51A-M3/5A has a maximum clamping voltage (VC) of 82.4 V when subjected to a 10/1000 μs waveform at a peak pulse current (IPPM) of 4.9 A. This value is measured per JEDEC standards and guarantees that downstream circuitry remains below destructive voltage thresholds during transient events. The SMAJ51A-M3/5A maintains this clamping performance across its full operating temperature range (–55 °C to +150 °C), with minimal variation due to its stable thermal coefficient.
Is the SMAJ51A-M3/5A suitable for automotive applications?
The SMAJ51A-M3/5A itself is not AEC-Q101 qualified, but it shares identical electrical characteristics and packaging with the AEC-Q101-certified SMAJ51AHM3_A/I variant. Its halogen-free M3 construction, 150 °C junction rating, and robust surge capability make it suitable for automotive prototype and non-safety-critical subsystems. For production automotive BOMs, the HM3 suffix version of SMAJ51A-M3/5A must be specified to meet OEM qualification requirements.
How does the SMAJ51A-M3/5A differ from bidirectional TVS diodes like SMAJ51CA?
The SMAJ51A-M3/5A is unidirectional and functions only in reverse-bias avalanche mode, with a defined cathode band for polarity-sensitive placement. In contrast, SMAJ51CA is bidirectional and symmetrical, clamping in both polarities-making it appropriate for AC signal lines or differential buses. The SMAJ51A-M3/5A offers lower leakage (1.0 μA vs. 2.0 μA for SMAJ51CA) and is preferred for DC power rail protection where polarity is fixed and leakage budget is tight.
What is the thermal resistance of the SMAJ51A-M3/5A, and how does it affect PCB layout?
The SMAJ51A-M3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on standard 0.2" × 0.2" copper pads. This value assumes no additional heatsinking; designers must allocate adequate copper area and avoid thermal isolation to prevent junction temperature exceeding 150 °C during repeated surge events. The device's RθJL of 30 °C/W indicates efficient heat transfer to PCB traces, supporting reliable operation in compact layouts typical of automotive ECUs and industrial sensors.
Can the SMAJ51A-M3/5A be used in parallel to increase surge current handling?
No-parallel connection of SMAJ51A-M3/5A devices is not recommended due to parameter mismatch (VBR tolerance, dynamic impedance) causing uneven current sharing and potential thermal runaway. For higher surge ratings, select a single higher-power device (e.g., SMBJ51A or SMCJ51A) or implement staged protection with upstream fusing. The SMAJ51A-M3/5A is optimized for discrete point-of-load protection, not modular scaling.
SMAJ51A-M3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- 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-M3/5A FAQ
1.How can I place an order for SMAJ51A-M3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51A-M3/5A 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-M3/5A reliable?
The price and inventory of SMAJ51A-M3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51A-M3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ51A-M3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51A-M3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51A-M3/5A?
SMAJ51A-M3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51A-M3/5A 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-M3/5A?
For technical support, including SMAJ51A-M3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51A-M3/5A requirements.
6.How does Aetrix verify that SMAJ51A-M3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ51A-M3/5A 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-M3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ51A-M3/5A?
All SMAJ51A-M3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51A-M3/5A, 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-M3/5A part is unused and in its original packaging.
Return procedure for SMAJ51A-M3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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