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Vishay General Semiconductor - Diodes Division SMAJ78A-M3/61
- Part No.:
- SMAJ78A-M3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ78A-M3/61.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,195
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Product details
Overview
SMAJ78A-M3/61 from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features a 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, 126 V maximum clamping voltage (VC) at 3.2 A peak pulse current, and 400 W peak pulse power rating with 10/1000 μs waveform - used to protect MOSFETs, ICs, and sensor interfaces in industrial power supplies and automotive control modules.
For engineers reviewing the SMAJ78A-M3/61 datasheet, SMAJ78A-M3/61 pinout, SMAJ78A-M3/61 application, or SMAJ78A-M3/61 equivalent, key selection criteria include unidirectional polarity, 126 V clamping performance at rated surge current, thermal resistance (RθJA = 120 °C/W), AEC-Q101 qualification eligibility (via HM3 suffix), and halogen-free RoHS compliance per M3 marking.
Technical Context
This TVS diode operates as a voltage-clamping protection device in parallel with sensitive circuit nodes. Its glass-passivated junction enables fast response (<1 ps) to ESD and lightning-induced surges, while low incremental surge resistance ensures stable clamping under repetitive 10/1000 μs transients up to 0.01% duty cycle.
The SMAJ78A-M3/61 is rated for 40 A peak forward surge current (IFSM, 8.3 ms half-sine), supports operating junction temperatures from –55 °C to +150 °C, and meets J-STD-020 MSL Level 1 with 260 °C reflow peak - confirming suitability for automated SMT assembly without moisture sensitivity concerns.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 86.7 V / 95.8 V at 1 mA - guaranteed breakdown range defining turn-on threshold tolerance |
| VC @ IPPM | 126 V at 3.2 A - clamped voltage during 10/1000 μs surge, limiting stress on downstream components |
| PPPM | 400 W - peak pulse power handling capability with standard 10/1000 μs waveform |
| ID @ VWM | 1.0 μA - ultra-low reverse leakage at stand-off voltage, minimizing standby power loss |
| RθJA | 120 °C/W - thermal resistance from junction to ambient, guiding PCB copper pad sizing for thermal management |
| Polarity | Unidirectional - cathode marked by band; blocks reverse conduction until breakdown |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, low-profile case with matte tin-plated leads solderable per J-STD-002 and JESD 22-B102. Molding compound meets UL 94 V-0.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / surge return path | Connected to protected line's lower-potential side (e.g., GND or low-side rail) |
| Cathode | Clamping node / surge sink | Marked with band; connected to protected line's higher-potential side (e.g., VBUS or signal line) |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power (10/1000 μs) | Enables robust protection against IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) on 12–48 V DC rails |
| 126 V clamping voltage at 3.2 A | Limits transient overvoltage to safe levels for 100 V-rated MOSFETs and logic-level gate drivers |
| Halogen-free, RoHS-compliant (M3 suffix) | Meets environmental compliance requirements for industrial and automotive end equipment |
| MSL Level 1, 260 °C peak reflow | Supports lead-free reflow without baking or special handling in high-volume SMT lines |
| Glass-passivated junction | Ensures stable VBR over temperature and long-term reliability under repeated surge stress |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Card |
|---|---|
Use Scenario: Protecting 24 V CAN bus interface circuits from load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed across VCC–GND and signal–GND to clamp transients before they reach CAN transceiver and microcontroller pins. Use Value: Clamps 126 V surges at 3.2 A, preventing latch-up or permanent damage to ISO 11898-compliant transceivers operating at 24 V nominal. |
Use Scenario: Safeguarding 24 V digital input channels from field-wiring induced surges in factory automation systems. IC Role / Device Role / Timing Role: Parallel-connected TVS on each optocoupler input leg to absorb energy from relay coil flyback and cable ESD events. Use Value: 400 W pulse rating and 1.0 μA leakage ensure reliable isolation integrity and minimal false triggering during steady-state operation. |
| Telecom Power Supply Front-End | Consumer Appliance Motor Drive Board |
Use Scenario: Secondary-side overvoltage suppression on 48 V telecom rectifier outputs feeding PoE injectors. IC Role / Device Role / Timing Role: Standoff-rated TVS on DC output rail to limit transient propagation into downstream DC/DC converters and Ethernet PHYs. Use Value: 78 V VWM aligns with 48 V ±10% regulation window; 126 V VC prevents exceedance of 100 V input ratings on isolated buck controllers. |
Use Scenario: Protection of MCU GPIOs and gate drivers from motor commutation spikes in smart washing machine control boards. IC Role / Device Role / Timing Role: Local TVS on H-bridge low-side driver supply and feedback signal lines to suppress <100 ns ringing and 1 kV EFT bursts. Use Value: Sub-nanosecond response and 120 °C/W RθJA allow direct placement near noise sources without thermal derating penalties. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78A-E3/61 | Same electrical specs; RoHS-compliant but not halogen-free (E3 vs. M3) | Acceptable where halogen-free requirement is not mandated (e.g., commercial-grade consumer products) | Select E3 for cost-sensitive non-automotive designs without halogen restrictions |
| SMAJ78AHE3_A/H | Identical electrical specs plus AEC-Q101 qualification; uses HE3 suffix and H tape/reel code | Required for automotive ECUs needing certified reliability (e.g., body electronics, ADAS sensors) | Choose HE3/HM3 variants when automotive qualification and traceability are mandatory |
Compared with SMAJ78A-M3/61, the E3 variant offers identical protection performance without halogen-free assurance, while the HE3 variant adds automotive qualification at higher cost and specific packaging - enabling precise alignment with tier-1 OEM BOM requirements.
Availability
SMAJ78A-M3/61 is available at Aetrix Electronics and suitable for industrial PLCs, automotive BCMs, telecom power supplies, and appliance motor drives requiring stable component supply with halogen-free compliance and SMT-ready packaging.
Supply support for SMAJ78A-M3/61 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, efficiency, and application-specific optimization.
The SMAJ series targets board-level transient protection in harsh environments - engineered for high surge immunity, tight VBR tolerances, and compatibility with automated manufacturing across automotive, industrial, and telecom sectors.
FAQ
What is the clamping voltage of the SMAJ78A-M3/61 under a 10/1000 μs surge?
The SMAJ78A-M3/61 has a maximum clamping voltage (VC) of 126 V at 3.2 A peak pulse current (IPPM) with a 10/1000 μs waveform. This value is measured per IEC 61000-4-5 test conditions and defines the upper voltage limit imposed on protected circuitry during standardized surge events. The SMAJ78A-M3/61 maintains this clamping performance across its specified operating temperature range.
Is the SMAJ78A-M3/61 suitable for automotive applications?
The SMAJ78A-M3/61 itself is not AEC-Q101 qualified; however, it shares identical electrical characteristics with the AEC-Q101-qualified SMAJ78AHE3_A/H and SMAJ78AHM3_A/H variants. For automotive use, select the HM3 or HE3 suffix versions - the SMAJ78A-M3/61 is appropriate for non-automotive industrial and telecom applications where halogen-free RoHS compliance is required but automotive qualification is not.
What does the "M3" suffix indicate in SMAJ78A-M3/61?
The "M3" suffix in SMAJ78A-M3/61 denotes halogen-free, RoHS-compliant construction meeting JEDEC J-STD-020 MSL Level 1 and JESD 201 Class 2 whisker resistance requirements. It distinguishes the part from the "E3" (RoHS-compliant but not halogen-free) and "HM3" (halogen-free + AEC-Q101 qualified) variants. The SMAJ78A-M3/61 is intended for commercial and industrial applications with strict environmental material mandates.
How does the SMAJ78A-M3/61 differ from bidirectional TVS diodes like SMAJ78CA?
The SMAJ78A-M3/61 is unidirectional and conducts only in reverse bias above VBR, with polarity marked by a cathode band. In contrast, SMAJ78CA is bidirectional and symmetrical - suppressing transients in both directions without polarity sensitivity. The SMAJ78A-M3/61 is used where DC bias exists (e.g., power rails), while SMAJ78CA suits AC-coupled or floating signal lines. Their VBR and VC values differ accordingly.
What is the thermal resistance and maximum junction temperature of the SMAJ78A-M3/61?
The SMAJ78A-M3/61 has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and a maximum junction temperature (TJ max.) of +150 °C. These parameters guide PCB layout - e.g., using 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal minimizes thermal impedance. The SMAJ78A-M3/61 remains within safe operating limits under 3.3 W steady-state power dissipation at TA = 50 °C.
SMAJ78A-M3/61 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):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 3.2A
- 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)
SMAJ78A-M3/61 FAQ
1.How can I place an order for SMAJ78A-M3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ78A-M3/61 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 SMAJ78A-M3/61 reliable?
The price and inventory of SMAJ78A-M3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ78A-M3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ78A-M3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ78A-M3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ78A-M3/61?
SMAJ78A-M3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ78A-M3/61 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 SMAJ78A-M3/61?
For technical support, including SMAJ78A-M3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ78A-M3/61 requirements.
6.How does Aetrix verify that SMAJ78A-M3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ78A-M3/61 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 SMAJ78A-M3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ78A-M3/61?
All SMAJ78A-M3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ78A-M3/61, 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 SMAJ78A-M3/61 part is unused and in its original packaging.
Return procedure for SMAJ78A-M3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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