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Vishay General Semiconductor - Diodes Division SMCJ78CA-E3/57T
- Part No.:
- SMCJ78CA-E3/57T
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ78CA-E3/57T.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:761
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Product details
Overview
SMCJ78CA-E3/57T from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, designed for high-energy surge protection with 78 V standoff voltage, 1500 W peak pulse power rating, and 126 V maximum clamping voltage at 11.9 A peak pulse current. It protects sensitive ICs, MOSFETs, and sensor signal lines in automotive, industrial, and telecom systems against inductive switching transients and lightning-induced surges.
For engineers reviewing the SMCJ78CA-E3/57T datasheet, SMCJ78CA-E3/57T pinout, SMCJ78CA-E3/57T application, or SMCJ78CA-E3/57T equivalent, this device is selected for robust bidirectional ESD/surge protection where low clamping ratio, fast response (<1 ns), and AEC-Q101 qualification (via HE3 variant) are critical - especially in 24 V/48 V DC power rails and CAN/LIN bus interfaces.
Technical Context
This bidirectional TVS operates symmetrically across both polarities, with breakdown voltage VBR = 86.7–95.8 V at 1 mA test current, standoff voltage VWM = 78 V, and reverse leakage ID ≤ 1.0 μA at VWM. Its clamping performance is specified under standardized 10/1000 μs waveform per ANSI/IEEE C62.35.
Thermally, it features RθJA = 75 °C/W (junction-to-ambient, on recommended 8.0 mm × 8.0 mm copper pads) and RθJL = 15 °C/W (junction-to-lead), enabling reliable operation up to TJ = +150 °C. The glass-passivated junction ensures stable surge handling and meets MSL Level 1 per J-STD-020.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Standoff Voltage) | 78 V - Maximum continuous reverse operating voltage before significant conduction begins; defines safe operating margin for 24 V/48 V systems. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Voltage range at which device enters avalanche breakdown; ensures predictable turn-on during overvoltage events. |
| VC (Clamping Voltage) | 126 V at IPPM = 11.9 A - Peak voltage seen by protected circuit during 10/1000 μs surge; determines stress on downstream components. |
| PPPM (Peak Pulse Power) | 1500 W - Maximum transient energy absorption capability under standard 10/1000 μs waveform; supports IEC 61000-4-5 Level 4 compliance. |
| IPPM (Peak Pulse Current) | 11.9 A - Surge current corresponding to VC; used to size PCB traces and verify system-level surge withstand. |
| TJmax | +150 °C - Maximum junction temperature; enables use in under-hood automotive and industrial environments without derating. |
| Package | SMC (DO-214AB) - Surface-mount package with 7.75 mm × 6.22 mm footprint and 3.20 mm height; compatible with automated placement and reflow. |
Pinout & Package
SMCJ78CA-E3/57T uses the SMC (DO-214AB) package - a bidirectional device with no polarity marking; both terminals are electrically symmetrical and interchangeable. The case is molded with UL 94 V-0 rated compound and features matte tin-plated leads solderable per J-STD-002.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Terminal 1 | Anode / Cathode (bidirectional) | Electrically identical to Terminal 2; no polarity - connects to either side of protected line (e.g., differential pair or single-ended rail). |
| Terminal 2 | Anode / Cathode (bidirectional) | Electrically identical to Terminal 1; enables symmetrical clamping for AC-coupled or floating signal paths. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection of AC signals, differential buses (e.g., RS-485, CAN), and floating power domains without polarity concerns. |
| 1500 W peak pulse power | Supports IEC 61000-4-5 surge immunity up to 4 kV (line-earth) and 2 kV (line-line) in properly designed systems. |
| Fast response time (<1 ns) | Clamps transients before they propagate into sensitive logic or analog front-ends, preserving signal integrity. |
| Low incremental surge resistance | Minimizes voltage overshoot during high-di/dt events, reducing stress on downstream MOSFETs and gate drivers. |
| AEC-Q101 qualified option | HE3 suffix variants meet automotive reliability requirements for engine control, body electronics, and ADAS power supplies. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
|
Use Scenario: Protecting 24 V supply inputs in engine control units (ECUs) and body control modules (BCMs) against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Bidirectional TVS placed across input rail and ground to clamp positive/negative transients within 126 V. Use Value: Prevents damage to PMICs and microcontrollers during alternator load dump (up to 60 V, 400 ms) and inductive switch-off spikes. |
Use Scenario: Shielding analog outputs (e.g., 4–20 mA, 0–10 V) and digital sensor interfaces (I²C, SPI) from ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-capacitance TVS connected between signal line and ground to suppress ±8 kV contact ESD (IEC 61000-4-2) without distorting signal edges. Use Value: Maintains sensor accuracy and communication integrity while meeting Class B EMC immunity requirements. |
| Telecom Data Line Surge Protection | DC Motor Drive Gate Protection |
|
Use Scenario: Safeguarding Ethernet PHYs, PoE injectors, and DSL line drivers against lightning-induced surges on twisted-pair cables. IC Role / Device Role / Timing Role: Bidirectional TVS deployed in common-mode configuration across differential pairs (e.g., TX+/TX−) to absorb longitudinal surges. Use Value: Enables compliance with ITU-T K.20/K.21 and GR-1089-CORE surge standards without adding series impedance. |
Use Scenario: Clamping flyback voltage spikes generated by brushed DC motor commutation in power tool and HVAC fan controllers. IC Role / Device Role / Timing Role: TVS placed across motor terminals or H-bridge high-side/low-side FETs to limit VDS stress during inductive turn-off. Use Value: Extends MOSFET lifetime by limiting peak drain-source voltage to 126 V, well below typical 100 V+ ratings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC78CA | Same VWM (78 V) and VC (126 V), but lower PPPM = 500 W; smaller SMA package (DO-214AC). | Lower surge capacity suits space-constrained consumer electronics; not suitable for automotive load dump or industrial 4 kV surges. | Select SAC78CA only when board area is critical and surge threat level is limited to IEC 61000-4-2 ESD or low-energy transients. |
| SMCJ78A-E3/57T | Unidirectional version with identical VWM, VBR, and VC, but cathode-marked; same SMC package and 1500 W rating. | Required only for DC-biased rails where negative transients are absent or blocked by upstream circuitry (e.g., regulated 12 V supply). | Choose SMCJ78A-E3/57T if protecting a unidirectional rail with known polarity; otherwise, SMCJ78CA-E3/57T provides safer, polarity-agnostic coverage. |
Compared with SAC78CA, SMCJ78CA-E3/57T delivers 3× higher surge energy handling in the same functional voltage class; versus SMCJ78A-E3/57T, it eliminates polarity dependency-critical for differential signaling and floating grounds-without sacrificing clamping performance or thermal robustness.
Availability
SMCJ78CA-E3/57T is available at Aetrix Electronics and suitable for automotive ECUs, industrial PLC I/O modules, telecom data line protectors, and DC motor drive circuits requiring stable component supply, RoHS-compliant manufacturing, and long-term production continuity.
Supply support for SMCJ78CA-E3/57T 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 SMCJ series was developed for high-power, surface-mount transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where robustness, repeatable clamping, and AEC-Q101 compliance are mandatory.
FAQ
What is the clamping voltage of SMCJ78CA-E3/57T at its rated peak pulse current?
The SMCJ78CA-E3/57T has a maximum clamping voltage VC of 126 V at IPPM = 11.9 A under the standard 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and represents the worst-case voltage imposed on the protected circuit during a full-rated surge event. Designers must ensure downstream components tolerate this voltage with margin.
Is SMCJ78CA-E3/57T suitable for automotive applications?
Yes - the base SMCJ78CA-E3/57T is RoHS-compliant and commercial-grade; however, the AEC-Q101 qualified version is designated SMCJ78CAHE3_A/H (or similar HE3 suffix). That variant undergoes extended reliability testing per automotive standards and is approved for under-hood and chassis-mounted ECUs. Always verify the specific suffix matches your qualification requirement.
How does SMCJ78CA-E3/57T differ from unidirectional SMCJ78A-E3/57T?
SMCJ78CA-E3/57T is bidirectional with symmetrical clamping in both polarities and no polarity marking, making it ideal for AC signals, differential buses, or floating grounds. SMCJ78A-E3/57T is unidirectional, marked with a cathode band, and conducts only in reverse bias - appropriate for DC rails with defined polarity. Both share identical VWM, VBR, VC, and PPPM.
What is the thermal resistance of SMCJ78CA-E3/57T, and how does it affect layout?
The SMCJ78CA-E3/57T has RθJA = 75 °C/W (junction-to-ambient) when mounted on the recommended 8.0 mm × 8.0 mm copper pads per terminal. To maintain TJ ≤ 150 °C under sustained power dissipation, designers must provide adequate copper area and avoid excessive ambient temperature. For high-reliability applications, thermal vias under the pads further reduce RθJA.
Can SMCJ78CA-E3/57T be used in parallel for higher surge current handling?
No - SMCJ78CA-E3/57T is not characterized for parallel operation. Variations in VBR tolerance (±10%) cause uneven current sharing, risking thermal runaway in one device. For higher surge capability, select a higher-rated part (e.g., SMCJ100CA) or implement staged protection with upstream current-limiting elements. Parallel use voids specification guarantees.
SMCJ78CA-E3/57T 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):
- 11.9A
- Power - Peak Pulse:
- 1500W (1.5kW)
- 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 (SMCJ)
SMCJ78CA-E3/57T FAQ
1.How can I place an order for SMCJ78CA-E3/57T through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ78CA-E3/57T 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 SMCJ78CA-E3/57T reliable?
The price and inventory of SMCJ78CA-E3/57T are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ78CA-E3/57T is usually 5 days.
3.What payment methods are accepted for SMCJ78CA-E3/57T?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ78CA-E3/57T transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ78CA-E3/57T?
SMCJ78CA-E3/57T orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ78CA-E3/57T 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 SMCJ78CA-E3/57T?
For technical support, including SMCJ78CA-E3/57T datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ78CA-E3/57T requirements.
6.How does Aetrix verify that SMCJ78CA-E3/57T is sourced from the original manufacturer or authorized distributors?
All SMCJ78CA-E3/57T 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 SMCJ78CA-E3/57T meets industry standards.
7.What is the process for return or replacement of SMCJ78CA-E3/57T?
All SMCJ78CA-E3/57T units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ78CA-E3/57T, 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 SMCJ78CA-E3/57T part is unused and in its original packaging.
Return procedure for SMCJ78CA-E3/57T:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMCJ78CA-E3/57T Tags
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