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Vishay General Semiconductor - Diodes Division SMAJ51CAHM3_A/H
- Part No.:
- SMAJ51CAHM3_A/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ51CAHM3_A/H.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,385
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Product details
Overview
SMAJ51CAHM3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection on signal and power lines. It features a 51 V standoff voltage (VWM), 56.7–62.7 V breakdown range (VBR), 82.4 V maximum clamping voltage (VC) at 4.9 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - deployed in automotive sensor interfaces, industrial I/O protection, and telecom line surge suppression.
For engineers reviewing the SMAJ51CAHM3_A/H datasheet, SMAJ51CAHM3_A/H pinout, SMAJ51CAHM3_A/H application, or SMAJ51CAHM3_A/H equivalent, key selection criteria include bidirectional clamping symmetry, AEC-Q101 qualification status, MSL Level 1 moisture sensitivity, and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector, responding within picoseconds to transients exceeding its reverse standoff voltage. Its bidirectional architecture ensures symmetrical clamping in both polarities, eliminating polarity dependency in AC-coupled or floating signal paths. The device uses a glass-passivated silicon junction optimized for low incremental surge resistance and stable thermal performance up to 150 °C junction temperature.
It is rated for 400 W peak pulse power (derated to 300 W above 78 V), with a 10/1000 μs waveform compliance per ANSI/IEEE C62.35. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), requiring minimum 0.2" × 0.2" copper pad area per terminal for full power derating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR (min/max) | 56.7 V / 62.7 V at 1 mA - Verified breakdown threshold ensuring reliable turn-on margin |
| VC @ IPPM | 82.4 V at 4.9 A - Clamped voltage during 10/1000 μs surge, limiting downstream stress |
| PPPM | 400 W - Peak transient energy absorption capability under standard waveform |
| IFSM | 40 A - Non-repetitive forward surge rating (8.3 ms half-sine), relevant for unidirectional testing |
| TJ max. | +150 °C - Maximum junction temperature enabling operation in under-hood automotive environments |
| MSL Level | Level 1 (J-STD-020) - No floor life limitation; safe for standard reflow without dry pack |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, halogen-free, RoHS-compliant, with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Bidirectional construction means no polarity marking; terminals are symmetric and interchangeable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (bidirectional) | Common transient path | Both terminals function identically; clamping occurs between them regardless of polarity |
| Case / Body | Non-connected mechanical element | No internal connection; serves only as thermal mass and mechanical anchor |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive applications including engine control modules and ADAS sensor interfaces |
| 400 W peak pulse power (10/1000 μs) | Withstands IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) when properly mounted |
| Low clamping ratio (VC/VBR ≈ 1.38) | Minimizes voltage overshoot during fast transients, protecting 5 V and 3.3 V logic interfaces |
| MSL Level 1, LF peak 260 °C | Compatible with lead-free reflow profiles without preconditioning or baking |
| Glass passivated junction | Ensures long-term reliability and stable leakage (<1 μA at VWM) across temperature and humidity |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting CAN FD and LIN bus transceivers from load dump and ISO 7637-2 pulses in vehicle body control modules. IC Role / Device Role / Timing Role: Shunt-type transient clamp placed directly at connector entry point, absorbing >95 % of surge energy before it reaches protected IC. Use Value: Enables compliance with ISO 16750-2 (12 V system, 35 V/1 s load dump) and maintains <100 ns response time to preserve signal integrity. | Use Scenario: Safeguarding 24 V digital input channels in programmable logic controllers exposed to relay coil flyback and ESD events. IC Role / Device Role / Timing Role: Primary front-end protection element on field-side PCB traces, placed before optocoupler or Schmitt trigger input stage. Use Value: Limits transient voltage to ≤82.4 V, preventing latch-up in 3.3 V microcontroller GPIOs powered via isolated DC-DC converters. |
| Telecom Line Interface | Consumer Power Adapter Output |
Use Scenario: Shielding Ethernet PHY magnetics and PoE injectors from lightning-induced surges on outdoor cabling. IC Role / Device Role / Timing Role: Secondary-level protector downstream of gas discharge tube (GDT), providing precise clamping after GDT crowbar action. Use Value: Delivers sub-100 ns response to complement slower primary protectors, reducing let-through voltage to <100 V for IEEE 802.3af/at compliance. | Use Scenario: Suppressing switching noise and output overvoltage spikes in 5 V/9 V USB-C PD adapters. IC Role / Device Role / Timing Role: Output rail clamp between secondary-side rectifier and bulk capacitor, guarding synchronous rectifier MOSFETs and USB port controllers. Use Value: Clamps 51 V nominal output to ≤82.4 V during 400 W transients, preventing overvoltage shutdown and maintaining UL 62368-1 fault tolerance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ51CAHE3_A/H | Same electrical specs; RoHS-compliant but not halogen-free; lacks HM3 suffix designation | Approved for commercial-grade automotive use but not certified to halogen-free material requirements | Select when halogen-free content is not mandated by end-customer specification |
| SMBJ51CAHM3_A/H | Same VWM/VC, but 600 W PPPM rating and SMB (DO-214AA) package (larger footprint, lower RθJA) | Better suited for higher-energy surges or thermally constrained layouts where 5.0 mm × 5.0 mm pads are insufficient | Choose when system-level surge testing exceeds IEC 61000-4-5 Level 4 or board space allows larger package |
Compared with SMAJ51CAHM3_A/H, SMAJ51CAHE3_A/H offers identical protection performance without halogen-free compliance, while SMBJ51CAHM3_A/H delivers 50 % higher surge power handling in a physically larger package - enabling trade-offs between board area, material compliance, and energy robustness.
Availability
SMAJ51CAHM3_A/H is available at Aetrix Electronics and suitable for automotive electronics, industrial control systems, and telecom infrastructure requiring stable component supply with AEC-Q101 qualification and halogen-free material compliance.
Supply support for SMAJ51CAHM3_A/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, MOSFETs, and protection devices with emphasis on reliability, precision, and automotive-grade validation.
The SMAJ series is engineered specifically for high-reliability transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where consistent clamping behavior and long-term stability under thermal cycling are critical.
FAQ
What does the 'HM3' suffix indicate in SMAJ51CAHM3_A/H?
The 'HM3' suffix in SMAJ51CAHM3_A/H denotes halogen-free, RoHS-compliant construction with AEC-Q101 qualification. It distinguishes this variant from non-halogen-free versions (e.g., HE3) and confirms compliance with automotive material standards. SMAJ51CAHM3_A/H is tested per JESD201 Class 2 whisker resistance and meets MSL Level 1 for reflow safety.
Is SMAJ51CAHM3_A/H bidirectional, and how does that affect circuit placement?
Yes, SMAJ51CAHM3_A/H is bidirectional, meaning it provides symmetrical clamping in both polarities without cathode/anode orientation constraints. This allows placement across any two points needing transient suppression - such as differential signal pairs or AC-coupled lines - without regard to polarity. No band marking is present on the SMA package.
What is the maximum clamping voltage of SMAJ51CAHM3_A/H, and under what test condition is it specified?
The maximum clamping voltage of SMAJ51CAHM3_A/H is 82.4 V, measured at 4.9 A peak pulse current (IPPM) using the standardized 10/1000 μs double-exponential waveform. This value defines the upper voltage limit imposed on protected circuitry during worst-case surge events, and is validated per ANSI/IEEE C62.35.
Can SMAJ51CAHM3_A/H be used in place of a unidirectional TVS like SMAJ51A?
No - SMAJ51CAHM3_A/H is strictly bidirectional and cannot replace unidirectional variants like SMAJ51A in circuits requiring forward conduction or DC bias blocking. Unidirectional types have a defined cathode and conduct in forward bias; SMAJ51CAHM3_A/H conducts equally in both directions and lacks polarity-dependent functionality.
What PCB layout guidance applies to SMAJ51CAHM3_A/H for optimal thermal and surge performance?
For optimal performance, SMAJ51CAHM3_A/H must be mounted on minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal to achieve full 400 W rating. Trace width should exceed 1.5 mm, and ground/power planes should be solid beneath the device. Avoid thermal reliefs on pads, and ensure symmetric routing to minimize inductance in the surge current path.
SMAJ51CAHM3_A/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:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- 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:
- 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)
SMAJ51CAHM3_A/H FAQ
1.How can I place an order for SMAJ51CAHM3_A/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ51CAHM3_A/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 SMAJ51CAHM3_A/H reliable?
The price and inventory of SMAJ51CAHM3_A/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ51CAHM3_A/H is usually 5 days.
3.What payment methods are accepted for SMAJ51CAHM3_A/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ51CAHM3_A/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ51CAHM3_A/H?
SMAJ51CAHM3_A/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ51CAHM3_A/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 SMAJ51CAHM3_A/H?
For technical support, including SMAJ51CAHM3_A/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ51CAHM3_A/H requirements.
6.How does Aetrix verify that SMAJ51CAHM3_A/H is sourced from the original manufacturer or authorized distributors?
All SMAJ51CAHM3_A/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 SMAJ51CAHM3_A/H meets industry standards.
7.What is the process for return or replacement of SMAJ51CAHM3_A/H?
All SMAJ51CAHM3_A/H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ51CAHM3_A/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 SMAJ51CAHM3_A/H part is unused and in its original packaging.
Return procedure for SMAJ51CAHM3_A/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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