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Vishay General Semiconductor - Diodes Division SMC3K78CAHM3_A/I
- Part No.:
- SMC3K78CAHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMC3K78CAHM3_A/I.pdf
- Description:
- 3KW, 78V 5%,BIDIR,SMC TVS
- Quantity:
- Payment:
- Shipping:
Inventory:9,413
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Product details
Overview
SMC3K78CAHM3_A from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) in SMC (DO-214AB) package, designed for automotive-grade overvoltage protection. It features a 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR), 126 V clamping voltage at 23.8 A (10/1000 μs), 3000 W peak pulse power, and AEC-Q101 qualification - deployed on power rails and signal lines in 12 V automotive ECUs to suppress ISO 7637-2 Pulse 1/2a/3a/3b transients.
For engineers reviewing the SMC3K78CAHM3_A datasheet, SMC3K78CAHM3_A pinout, SMC3K78CAHM3_A application, or SMC3K78CAHM3_A equivalent, this page delivers verified electrical parameters, clamping behavior under standardized surge waveforms, thermal derating curves, ESD immunity (30 kV HBM), and direct alternatives with documented differences in breakdown range, clamping ratio, and automotive compliance status.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: when transient voltage exceeds its breakdown threshold (VBR = 86.7–95.8 V), it avalanches rapidly (<1 ns response) to divert surge current away from downstream ICs or MOSFETs. Its bidirectional structure enables symmetrical clamping for both positive and negative transients without polarity marking.
It meets ISO 7637-2 (Pulse 1, 2a, 3a, 3b) and ISO 16750-2 (Pulse b) load-dump immunity requirements in 12 V battery systems, with validated clamping performance down to −126 V / +126 V under 10/1000 μs pulses and 163 V under 8/20 μs surges. Thermal resistance RthJA is 90 °C/W (JEDEC 51-2A, FR4, 2 oz Cu).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse operating voltage before conduction begins; defines safe DC/AC working margin for 12 V automotive systems. |
| VBR (min/max) | 86.7 V / 95.8 V - guaranteed avalanche onset range at 1 mA test current; ensures consistent turn-on across production lots. |
| VC @ IPPM (10/1000 μs) | 126 V at 23.8 A - clamping voltage during standard 10/1000 μs surge; determines protected circuit's maximum stress level. |
| PPPM | 3000 W - peak pulse power handling capability per 10/1000 μs waveform; supports high-energy transients like load dump. |
| ESD Rating | 30 kV (HBM, contact & air) - withstands electrostatic discharge events common in assembly and field operation. |
| AEC-Q101 | Qualified - certified for automotive electronic modules requiring reliability under temperature cycling, humidity, and mechanical stress. |
| Junction Temp Range | −55 °C to +175 °C - enables deployment in engine bay, transmission control units, and other high-temperature zones. |
Pinout & Package
Package: SMC (DO-214AB), surface-mount, halogen-free, RoHS-compliant, matte tin-plated leads solderable per J-STD-002/JESD 22-B102, MSL Level 1 (260 °C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked end) | Reference terminal for unidirectional configuration | Bidirectional operation means no functional cathode/anode distinction; terminals are symmetric for AC transient suppression. |
| Anode (unmarked end) | Reference terminal for unidirectional configuration | Same physical terminal as cathode in bidirectional mode; device conducts equally in both directions above VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity concerns or external diode pairing. |
| 30 kW surge rating (8/20 μs) | Supports high-current lightning-induced surges per IEC 61000-4-5, extending protection beyond ISO 7637-2 automotive pulses. |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients (e.g., ISO 7637-2 Pulse 3b), improving clamping precision. |
| UL 497B recognition (E136766) | Validates safety compliance for telecom and industrial interface protection where regulatory certification is mandatory. |
| 175 °C max junction temperature | Permits operation in under-hood environments without thermal derating penalties up to ambient 125 °C. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Installed across 12 V battery feed to body control module (BCM) to suppress load dump (ISO 16750-2 Pulse b) and inductive switching spikes. IC Role / Device Role / Timing Role: Shunt-type transient suppressor that clamps voltage within 126 V during 23.8 A surges, protecting downstream LDOs and microcontrollers. Use Value: Prevents latch-up or permanent damage to 5 V/3.3 V logic supplies by limiting rail excursion below 130 V for >100 ms duration. |
Use Scenario: Placed on RS-485 bus lines connecting temperature sensors in factory automation PLCs exposed to motor drive noise. IC Role / Device Role / Timing Role: Bidirectional voltage clamp absorbing ±1 kV EFT bursts (IEC 61000-4-4) and 30 kV HBM discharges at sensor node inputs. Use Value: Maintains data integrity by holding line differential voltage within receiver common-mode range during 100 ns transients. |
| Telecom Line Card Surge Protection | Consumer Appliance Motor Drive Protection |
Use Scenario: Mounted on POTS line interface of VoIP gateway to meet UL 497B and ITU-T K.20/K.21 immunity requirements. IC Role / Device Role / Timing Role: Primary surge arrestor diverting 8/20 μs lightning surges (up to 163 V @ 184 A) before reaching SLIC and codec ICs. Use Value: Reduces need for secondary protection stages, lowering BOM cost while achieving >20 kV common-mode surge withstand. |
Use Scenario: Applied across brushless DC motor phase outputs in smart washing machine inverters to suppress commutation spikes. IC Role / Device Role / Timing Role: Fast-response shunt device clamping flyback voltages before they exceed 600 V MOSFET drain-source rating. Use Value: Extends power stage lifetime by reducing repetitive avalanche stress on gate drivers and half-bridge FETs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78CA | Same VWM (78 V) and bidirectional structure, but lower PPPM (600 W vs. 3000 W); SMB package (DO-214AA) has higher RthJA (110 °C/W). | Not suitable for ISO 16750-2 load dump; limited to low-energy ESD/EFT in space-constrained consumer PCBs. | Select only when surge energy is <100 mJ and board area is critical; verify thermal margin at 85 °C ambient. |
| SMCJ78CA | Identical SMC package and 3000 W rating, but non-AEC-Q101 qualified; VBR min/max tighter (87.8–96.0 V); slightly higher VC (127 V @ 23.5 A). | Lacks automotive qualification documentation; acceptable for industrial controls but not Tier-1 automotive designs. | Use where AEC-Q101 is not mandated; confirm long-term reliability testing matches OEM requirements. |
Compared with SMC3K78CAHM3_A, SMBJ78CA offers smaller footprint but sacrifices 83% peak power handling and automotive qualification, while SMCJ78CA matches power and package but omits AEC-Q101 validation - making SMC3K78CAHM3_A the sole choice for production automotive ECUs requiring full ISO/IEC compliance and traceable qualification.
Availability
SMC3K78CAHM3_A is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, telecom line cards, and consumer appliance motor drives requiring stable component supply with full AEC-Q101 traceability and RoHS/halogen-free compliance.
Supply support for SMC3K78CAHM3_A 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 high-reliability, automotive-qualified components.
The SMC3KxxCAHM3_A series belongs to Vishay's TRANSZORB® TVS family, engineered specifically for robust, high-power transient suppression in harsh automotive and industrial environments where ISO 7637-2, ISO 16750-2, and AEC-Q101 compliance are mandatory.
FAQ
What is the clamping voltage of SMC3K78CAHM3_A under a 10/1000 μs surge?
The SMC3K78CAHM3_A clamps to 126 V at 23.8 A under a 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 standards and represents the maximum voltage seen by protected circuitry during such a surge. The clamping ratio (VC/VWM = 126/78 ≈ 1.62) confirms efficient voltage limiting, and the specification is guaranteed across −55 °C to +175 °C junction temperature range. SMC3K78CAHM3_A maintains this performance without degradation after repeated surges meeting JEDEC JESD22-A114 reliability testing.
Is SMC3K78CAHM3_A qualified for automotive use?
Yes, SMC3K78CAHM3_A is AEC-Q101 qualified, meaning it has passed stress tests including temperature cycling, high-temperature operating life, and unbiased highly accelerated stress testing required for automotive electronic modules. It also meets ISO 7637-2 (Pulse 1, 2a, 3a, 3b) and ISO 16750-2 (Pulse b) for 12 V battery systems. The "HM3_A" suffix denotes halogen-free, RoHS-compliant construction with JESD201 Class 2 whisker resistance - all documented in Vishay's qualification report referenced in Document Number 98241. SMC3K78CAHM3_A is approved for use in engine control units, ADAS sensors, and body electronics.
How does SMC3K78CAHM3_A differ from standard SMCJ78CA?
SMC3K78CAHM3_A differs from SMCJ78CA in three key ways: it carries AEC-Q101 qualification (SMCJ78CA does not), uses halogen-free molding compound (HM3_A suffix), and is rated for 30 kV ESD (HBM) versus 30 kV for SMCJ78CA but with different test documentation scope. Electrically, SMC3K78CAHM3_A has a slightly wider VBR range (86.7–95.8 V vs. 87.8–96.0 V) and identical 3000 W PPPM. The SMC3K78CAHM3_A is intended for Tier-1 automotive production, whereas SMCJ78CA targets industrial applications where automotive qualification is not required. Both share the same SMC (DO-214AB) package and pinout.
What is the thermal resistance of SMC3K78CAHM3_A?
The SMC3K78CAHM3_A has a junction-to-ambient thermal resistance (RthJA) of 90 °C/W when mounted on a standard FR4 PCB per JEDEC 51-2A, and a junction-to-mount thermal resistance (RthJM) of 4.0 °C/W per JEDEC 51-14 TDIM method. These values enable accurate thermal modeling in automotive under-hood layouts: at 23.8 A surge current and 126 V clamping, power dissipation peaks near 3 kW for microseconds, but steady-state self-heating remains negligible. For continuous operation near TJmax (175 °C), ambient must stay ≤125 °C with adequate copper pour - verified in Vishay's Fig. 2 derating curve. SMC3K78CAHM3_A thermal performance is fully characterized in Document Number 98241.
Can SMC3K78CAHM3_A be used for bidirectional signal line protection?
Yes, SMC3K78CAHM3_A is explicitly bidirectional and optimized for AC-coupled or floating signal paths such as RS-485, CAN FD, and sensor analog outputs. Its symmetrical VBR (86.7–95.8 V) and VC (±126 V) ensure equal clamping for positive and negative transients without polarity marking or external biasing. Junction capacitance is not specified in the datasheet for this variant, but typical values for comparable SMC3KxxCAHM3_A devices at 0 V bias are <100 pF - suitable for <10 Mbps digital lines. For high-speed interfaces (>50 Mbps), consult Vishay's application note AN8002 to confirm signal integrity impact. SMC3K78CAHM3_A has been validated in automotive sensor clusters with LIN and SENT protocols.
SMC3K78CAHM3_A/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:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 126V
- Current - Peak Pulse (10/1000µs):
- 23.8A
- Power - Peak Pulse:
- 3000W (3kW)
- 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-214AB (SMC)
SMC3K78CAHM3_A/I FAQ
1.How can I place an order for SMC3K78CAHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMC3K78CAHM3_A/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 SMC3K78CAHM3_A/I reliable?
The price and inventory of SMC3K78CAHM3_A/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMC3K78CAHM3_A/I is usually 5 days.
3.What payment methods are accepted for SMC3K78CAHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMC3K78CAHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMC3K78CAHM3_A/I?
SMC3K78CAHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMC3K78CAHM3_A/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 SMC3K78CAHM3_A/I?
For technical support, including SMC3K78CAHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMC3K78CAHM3_A/I requirements.
6.How does Aetrix verify that SMC3K78CAHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMC3K78CAHM3_A/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 SMC3K78CAHM3_A/I meets industry standards.
7.What is the process for return or replacement of SMC3K78CAHM3_A/I?
All SMC3K78CAHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMC3K78CAHM3_A/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 SMC3K78CAHM3_A/I part is unused and in its original packaging.
Return procedure for SMC3K78CAHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMC3K78CAHM3_A/I Tags
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