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Vishay General Semiconductor - Diodes Division SMC5K78A-M3/I
- Part No.:
- SMC5K78A-M3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMC5K78A-M3/I.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:9,381
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Product details
Overview
SMC5K78A-M3/I from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMC (DO-214AB) package, designed for high-energy surge protection 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 clamping voltage (VC) at 39.7 A (10/1000 μs), 5000 W peak pulse power, and AEC-Q101 qualification for automotive-grade reliability.
For engineers reviewing the SMC5K78A-M3/I datasheet, SMC5K78A-M3/I pinout, SMC5K78A-M3/I application, or SMC5K78A-M3/I equivalent, this device serves as a robust, surface-mount solution for protecting MOSFETs, ICs, and sensor signal lines against lightning-induced transients and inductive switching surges in industrial and automotive systems.
Technical Context
This TVS diode operates with unidirectional polarity-cathode marked by a band-and delivers precise clamping response under standardized 10/1000 μs and 8/20 μs surge waveforms. Its low incremental surge resistance and fast response time ensure minimal voltage overshoot during transient events.
Thermal performance is defined by RthJA = 90 °C/W (JEDEC 51-2A, FR4, 2 oz copper) and RthJM = 4.0 °C/W (JEDEC 51-14 TDIM), enabling reliable operation up to TJ = +150 °C. It meets IEC 61000-4-2 ESD immunity at ±30 kV (contact/air mode) and UL 497B safety recognition (E136766).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - Maximum continuous reverse operating voltage before clamping begins; defines safe operating margin for 72–80 V DC rails. |
| VBR (min/max) | 86.7 V / 95.8 V at 1 mA - Tight breakdown tolerance ensures predictable turn-on across temperature and production lot. |
| VC @ IPPM | 126 V at 39.7 A (10/1000 μs) - Clamping voltage limits downstream component stress during 5000 W surge events. |
| PPPM | 5000 W - Peak pulse power rating per 10/1000 μs waveform; supports high-energy transient suppression without failure. |
| TJ max. | +150 °C - Enables use in under-hood automotive and industrial environments with elevated ambient temperatures. |
| ESD Rating | ±30 kV HBM (contact/air) - Meets IEC 61000-4-2 Level 4 for system-level electrostatic discharge robustness. |
| Package | SMC (DO-214AB) - Industry-standard surface-mount outline with 3.20 mm × 6.22 mm footprint and 2.06 mm height; RoHS/halogen-free (M3 suffix). |
Pinout & Package
SMC5K78A-M3/I uses the standard SMC (DO-214AB) package: cathode indicated by a color band on the body; anode and cathode are axial terminals on opposite ends of the molded case. The device is mounted with solderable matte tin-plated leads compliant with J-STD-002 and JESD 22-B102.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; connected to lower-potential side of protected line | Provides reference path for clamping action; must be routed to ground or return rail in unidirectional configuration. |
| Cathode | Current exit terminal in forward bias; marked by color band; connected to protected line | Defines polarity-sensitive connection point; clamps transients above VWM by shunting current to anode/ground. |
Key Features
| Feature | Design Value |
|---|---|
| 5000 W peak pulse power (10/1000 μs) | Enables protection against severe load-dump and lightning-surge events without thermal runaway in compact SMC footprint. |
| 126 V clamping at 39.7 A | Limits voltage seen by downstream 80 V-rated MOSFETs or microcontrollers during worst-case 10/1000 μs transients. |
| AEC-Q101 qualified (industrial grade variant) | Validated for automotive subsystems where full AEC-Q101 compliance is not required but high-reliability screening is mandated. |
| UL 497B recognized (E136766) | Confirms suitability for telecom and industrial equipment requiring certified surge protection per safety standards. |
| MSL Level 1, 260 °C reflow compatible | Supports lead-free assembly without preconditioning; eliminates moisture-related popcorning during PCB reflow. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: Protecting 72–80 V battery-fed ECUs and lighting modules from ISO 7637-2 load dump pulses. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp overvoltage spikes within microseconds. Use Value: Limits peak voltage to ≤126 V, preventing damage to 80 V-rated gate drivers and CAN transceivers in engine control units. |
Use Scenario: Shielding analog output lines of pressure/temperature sensors in factory automation PLCs from motor-switching noise. IC Role / Device Role / Timing Role: Low-capacitance TVS installed at connector interface to absorb 8/20 μs surges induced by nearby relay coils. Use Value: Maintains signal integrity with <100 pF junction capacitance at zero bias while suppressing >30 A transients without latch-up. |
| Telecom DC Power Input Protection | Computer PSU Overvoltage Clamp |
Use Scenario: Safeguarding -48 V DC input stages of base station power supplies against lightning-induced common-mode surges. IC Role / Device Role / Timing Role: Cathode-connected to -48 V rail, anode to ground; clamps negative-going transients exceeding VWM magnitude. Use Value: Withstands 5000 W surges and maintains UL 497B certification for telecom infrastructure deployment. |
Use Scenario: Secondary-side overvoltage clamp on +12 V or +5 V outputs of ATX PSUs to prevent catastrophic failure during regulator fault conditions. IC Role / Device Role / Timing Role: Fast-response TVS placed across output capacitor to divert excess energy before downstream logic ICs exceed absolute maximum ratings. Use Value: Clamps to 126 V within nanoseconds, protecting 16 V-tolerant VRMs and USB controllers during 10/1000 μs faults. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78A-M3/5A | Lower PPPM (600 W), SMB package (smaller footprint), same VWM/VBR range, identical clamping (126 V @ 4.7 A) | Not suitable for 5000 W surges; limited to low-energy signal-line or secondary-side protection | Select when space-constrained layouts require smaller SMB package and surge energy is ≤600 W. |
| SMC5K75A-M3/I | 75 V VWM, 83.3–92.1 V VBR, 121 V VC @ 41.3 A; 500 W lower clamping voltage margin vs. SMC5K78A-M3/I | Better fit for 72 V nominal rails with tighter clamping headroom; slightly reduced surge current handling | Choose for designs prioritizing lower clamping voltage over higher VWM margin, especially in 75 V system architectures. |
Compared with SMBJ78A-M3/5A and SMC5K75A-M3/I, the SMC5K78A-M3/I uniquely balances 78 V stand-off, 126 V clamping, and 5000 W surge capability in the robust SMC package-making it optimal for primary-side automotive and industrial power rail protection where both voltage margin and energy absorption are critical.
Availability
SMC5K78A-M3/I is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interfaces, telecom DC inputs, and computer PSU overvoltage protection requiring stable component supply across extended product lifecycles.
Supply support for SMC5K78A-M3/I 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 devices, and power MOSFETs with emphasis on reliability, efficiency, and application-specific optimization.
The SMC5K78A-M3/I belongs to Vishay's TRANSZORB® family of high-power TVS diodes, engineered specifically for ruggedized transient suppression in harsh electrical environments including automotive, industrial, and telecom infrastructure.
FAQ
What is the maximum clamping voltage of the SMC5K78A-M3/I under a 10/1000 μs surge?
The SMC5K78A-M3/I has a maximum clamping voltage (VC) of 126 V at 39.7 A under a 10/1000 μs waveform, as specified in the Vishay datasheet (Document Number: 87742). This value defines the upper voltage limit imposed on protected circuitry during standardized surge events and is measured with the device operating at TA = 25 °C. The SMC5K78A-M3/I maintains this clamping performance across its rated junction temperature range.
Is the SMC5K78A-M3/I AEC-Q101 qualified?
No, the SMC5K78A-M3/I is not AEC-Q101 qualified. Per the Vishay datasheet, AEC-Q101 qualification applies only to SMC5K10A through SMC5K20A variants with HM3 suffix (e.g., SMC5K20AHM3_A/I). The SMC5K78A-M3/I is designated for industrial-grade applications and carries the M3 halogen-free/RoHS-compliant suffix without automotive qualification.
What does the "-M3/I" suffix indicate in SMC5K78A-M3/I?
The "-M3/I" suffix in SMC5K78A-M3/I denotes two key attributes: "M3" specifies halogen-free, RoHS-compliant construction meeting JESD 201 Class 2 whisker resistance, and "I" indicates packaging in 13-inch diameter plastic tape and reel with a base quantity of 3500 units. This differs from "H"-suffixed versions, which use 7-inch reels with 850-unit quantities.
Can the SMC5K78A-M3/I be used in bidirectional configurations?
No, the SMC5K78A-M3/I is a unidirectional TVS diode, as confirmed by its polarity marking (cathode band) and electrical specifications-including single-quadrant VBR and VC ratings. Bidirectional protection requires either a dedicated bidirectional TVS (e.g., SMC5K78CA) or back-to-back unidirectional devices; the SMC5K78A-M3/I must be oriented with cathode toward the protected line.
What is the thermal resistance from junction to ambient (RthJA) for the SMC5K78A-M3/I?
The SMC5K78A-M3/I has a typical junction-to-ambient thermal resistance (RthJA) of 90 °C/W, measured per JEDEC 51-2A on FR4 PCB with 2 oz copper. This value assumes standard SMC mounting pad layout and is critical for calculating steady-state power dissipation limits and transient thermal behavior during repetitive surge events. Derating curves in the datasheet guide safe operation above TA = 25 °C.
SMC5K78A-M3/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AB, SMC
- 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):
- 39.7A
- Power - Peak Pulse:
- 5000W (5kW)
- 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-214AB (SMC)
SMC5K78A-M3/I FAQ
1.How can I place an order for SMC5K78A-M3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMC5K78A-M3/I 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 SMC5K78A-M3/I reliable?
The price and inventory of SMC5K78A-M3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMC5K78A-M3/I is usually 5 days.
3.What payment methods are accepted for SMC5K78A-M3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMC5K78A-M3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMC5K78A-M3/I?
SMC5K78A-M3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMC5K78A-M3/I 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 SMC5K78A-M3/I?
For technical support, including SMC5K78A-M3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMC5K78A-M3/I requirements.
6.How does Aetrix verify that SMC5K78A-M3/I is sourced from the original manufacturer or authorized distributors?
All SMC5K78A-M3/I 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 SMC5K78A-M3/I meets industry standards.
7.What is the process for return or replacement of SMC5K78A-M3/I?
All SMC5K78A-M3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMC5K78A-M3/I, 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 SMC5K78A-M3/I part is unused and in its original packaging.
Return procedure for SMC5K78A-M3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMC5K78A-M3/I Tags
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