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Vishay General Semiconductor - Diodes Division SMCJ78CA-E3/9AT
- Part No.:
- SMCJ78CA-E3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ78CA-E3/9AT.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:3,889
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Product details
Overview
SMCJ78CA-E3/9AT from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMC (DO-214AB) package, designed for robust overvoltage protection of sensitive electronics. It features a 78 V standoff voltage (VWM), 126 V maximum clamping voltage (VC) at 11.9 A peak pulse current (IPPM), and 1500 W peak pulse power dissipation (PPPM) under 10/1000 μs waveform - deployed on power rails and signal lines in automotive ECUs and industrial I/O modules.
For engineers reviewing the SMCJ78CA-E3/9AT datasheet, SMCJ78CA-E3/9AT pinout, SMCJ78CA-E3/9AT application, or SMCJ78CA-E3/9AT equivalent, key selection criteria include bidirectional clamping symmetry, low incremental surge resistance, AEC-Q101 qualification eligibility, RoHS-compliant matte tin plating, and compatibility with automated SMT placement on 8.0 mm × 8.0 mm copper pads.
Technical Context
This device operates as a voltage-clamping protector using an avalanche breakdown mechanism, with symmetrical bidirectional behavior validated across both polarities. Its glass-passivated junction ensures stable breakdown characteristics and fast response time (<1 ns), while the SMC package provides thermal resistance of 75 °C/W (junction-to-ambient) and 15 °C/W (junction-to-lead).
The SMCJ78CA-E3/9AT is rated for -55 °C to +150 °C operating junction temperature, supports 1.0 μA max reverse leakage at VWM, and meets MSL Level 1 per J-STD-020 with peak reflow temperature up to 260 °C - enabling reliable use in high-reliability automotive and industrial environments without derating penalties below 25 °C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse working voltage before clamping initiates |
| VBR min/max | 86.7 V / 95.8 V at 1 mA - guaranteed breakdown voltage range defining turn-on threshold |
| VC @ IPPM | 126 V at 11.9 A - clamped voltage during full-rated 1500 W transient, limiting downstream stress |
| PPPM | 1500 W - peak pulse power handling capability under standardized 10/1000 μs surge waveform |
| ID @ VWM | 1.0 μA - ultra-low reverse leakage ensuring minimal standby power loss and signal integrity |
| TJ max | +150 °C - maximum junction temperature enabling operation in under-hood automotive locations |
| Package | SMC (DO-214AB) - surface-mount outline with 7.75 mm × 8.13 mm footprint and 3.20 mm height |
Pinout & Package
SMCJ78CA-E3/9AT uses a 2-terminal SMC (DO-214AB) package with no polarity marking - consistent with bidirectional TVS construction. Terminals are matte tin-plated leads, solderable per J-STD-002 and JESD 22-B102, and meet JESD 201 Class 2 whisker test requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient return path (bidirectional) | Provides symmetrical conduction path during positive or negative transients; no cathode band marking |
| Cathode | Transient return path (bidirectional) | Electrically identical to anode in CA-series devices; terminals interchangeable in layout |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Identical VBR, VC, and IPPM performance in both directions - eliminates polarity concerns in AC-coupled or floating signal lines |
| Glass passivated junction | Enhanced long-term stability and reduced parameter drift under thermal cycling and humidity exposure |
| Low incremental surge resistance | Enables tighter clamping (126 V at 11.9 A) versus competing 78 V TVS devices, reducing protected circuit voltage overshoot |
| AEC-Q101 qualification option | Available in HE3/HM3 variants - supports automotive-grade reliability validation without redesigning protection topology |
| MSL Level 1 rating | Allows direct placement into standard SMT reflow profiles (peak 260 °C) without dry-pack or baking requirements |
Applications
| Automotive Power Rail Protection | Industrial Sensor Signal Line Protection |
|---|---|
Use Scenario: Protecting 12 V/24 V battery-fed microcontroller power inputs against load dump and jump-start transients in body control modules. IC Role / Device Role / Timing Role: Voltage-clamping TVS placed directly at power entry point, shunting >100 V spikes within nanoseconds. Use Value: Limits rail voltage to ≤126 V during 1500 W surges, preventing latch-up or permanent damage to 5 V LDOs and MCU cores. | Use Scenario: Safeguarding analog outputs (e.g., 4–20 mA current loops) and digital I²C/SPI lines in factory-floor pressure/temperature sensors. IC Role / Device Role / Timing Role: Bidirectional transient suppressor bridging signal line to ground, activated by ESD or inductive switching noise. Use Value: Clamps ±126 V transients while maintaining <1.0 μA leakage at 78 V, preserving signal accuracy and minimizing offset error. |
| Telecom Interface Port Protection | Consumer Device USB/DC Jack Protection |
Use Scenario: Shielding RS-485 transceiver pins and Ethernet PHY magnetics interfaces from lightning-induced surges in outdoor base stations. IC Role / Device Role / Timing Role: Primary-level TVS on differential bus lines, coordinated with secondary GDT or polymer PTC devices. Use Value: Withstands repeated 10/1000 μs surges up to 1500 W, meeting ITU-T K.21 basic protection requirements for telecom infrastructure. | Use Scenario: Hardening DC input jacks and USB VBUS lines in portable medical monitors and smart home hubs against user-handling ESD and adapter plug-in spikes. IC Role / Device Role / Timing Role: First-line clamping device between connector and input filter capacitor, absorbing energy before it reaches PMIC. Use Value: 126 V clamping voltage prevents overvoltage stress on 5 V USB switch ICs and enables compliance with IEC 61000-4-2 Level 4 (±15 kV air). |
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 | Lower PPPM (600 W), same VWM (78 V), smaller SMA package (DO-214AC) | Reduced surge handling; suitable only for lower-energy threats (e.g., board-level ESD) | Select when space-constrained layouts preclude SMC and threat level is limited to IEC 61000-4-2 |
| SMCJ78A-E3/9AT | Unidirectional version; identical VWM, VC, and PPPM but asymmetric conduction (cathode-banded) | Requires polarity-aware layout; unsuitable for AC or floating signals without series blocking diode | Choose only when protecting DC rails with known polarity and need for slightly lower ID (0.5 μA vs. 1.0 μA) |
Compared with SAC78CA and SMCJ78A-E3/9AT, the SMCJ78CA-E3/9AT uniquely delivers 1500 W bidirectional clamping in SMC package - making it the sole choice for high-energy, polarity-agnostic protection in automotive and industrial power domains without compromising PCB real estate or thermal margin.
Availability
SMCJ78CA-E3/9AT is available at Aetrix Electronics and suitable for automotive ECU design, industrial PLC I/O modules, telecom base station interface protection, and consumer DC power input hardening requiring stable component supply and full traceability.
Supply support for SMCJ78CA-E3/9AT 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 is engineered for high-power transient suppression in harsh environments - targeting automotive, industrial, and telecom systems where robustness against ISO 7637-2 load dump, IEC 61000-4-5 surges, and repetitive ESD events is mandatory.
FAQ
What is the clamping voltage of SMCJ78CA-E3/9AT at its rated peak pulse current?
The SMCJ78CA-E3/9AT has a maximum clamping voltage (VC) of 126 V at its rated peak pulse current (IPPM) of 11.9 A under the standard 10/1000 μs waveform. This value is measured across both terminals during transient conduction and reflects the upper limit of voltage imposed on protected circuitry during worst-case surge events. The SMCJ78CA-E3/9AT maintains this clamping performance symmetrically in either polarity due to its bidirectional construction.
Is SMCJ78CA-E3/9AT suitable for automotive applications requiring AEC-Q101 qualification?
The SMCJ78CA-E3/9AT itself is the commercial-grade RoHS-compliant variant; however, Vishay offers AEC-Q101 qualified versions under ordering codes SMCJ78CAHE3_X (RoHS + AEC-Q101) and SMCJ78CAHM3_X (halogen-free + AEC-Q101). These share identical electrical specs and SMC package with SMCJ78CA-E3/9AT but undergo additional stress testing per AEC-Q101. For production automotive use, specify the HE3 or HM3 suffix rather than E3/9AT.
How does the bidirectional nature of SMCJ78CA-E3/9AT affect PCB layout compared to unidirectional TVS diodes?
The SMCJ78CA-E3/9AT has no polarity marking and identical electrical behavior in both directions, allowing placement without orientation constraints - unlike unidirectional variants such as SMCJ78A-E3/9AT, which require correct cathode alignment. This simplifies layout, reduces assembly errors, and enables use on AC-coupled, differential, or floating signal paths where voltage polarity reverses. The SMCJ78CA-E3/9AT's terminals are functionally interchangeable in schematic and layout.
What is the thermal resistance profile of SMCJ78CA-E3/9AT, and how does it impact power derating?
The SMCJ78CA-E3/9AT exhibits a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W and junction-to-lead resistance (RθJL) of 15 °C/W when mounted on minimum recommended 8.0 mm × 8.0 mm copper pads. Derating begins above 25 °C ambient per Figure 2 in the datasheet: at 70 °C ambient, its peak pulse power drops to ~1100 W. The SMCJ78CA-E3/9AT's low RθJL supports effective heat transfer to PCB copper, critical for repeated surge duty cycles in enclosed enclosures.
Can SMCJ78CA-E3/9AT be used in parallel to increase surge current handling?
No - paralleling SMCJ78CA-E3/9AT devices is not recommended due to mismatch in breakdown voltage (VBR tolerance ±5%) causing uneven current sharing and potential thermal runaway. Vishay specifies single-device operation only. For higher surge ratings, select a higher-power TVS family (e.g., 5.0SMDJ series, 5000 W) or implement staged protection with upstream GDT + downstream SMCJ78CA-E3/9AT. The SMCJ78CA-E3/9AT must operate individually per its published PPPM and IPPM ratings.
SMCJ78CA-E3/9AT 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-E3/9AT FAQ
1.How can I place an order for SMCJ78CA-E3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ78CA-E3/9AT 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-E3/9AT reliable?
The price and inventory of SMCJ78CA-E3/9AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ78CA-E3/9AT is usually 5 days.
3.What payment methods are accepted for SMCJ78CA-E3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ78CA-E3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ78CA-E3/9AT?
SMCJ78CA-E3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ78CA-E3/9AT 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-E3/9AT?
For technical support, including SMCJ78CA-E3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ78CA-E3/9AT requirements.
6.How does Aetrix verify that SMCJ78CA-E3/9AT is sourced from the original manufacturer or authorized distributors?
All SMCJ78CA-E3/9AT 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-E3/9AT meets industry standards.
7.What is the process for return or replacement of SMCJ78CA-E3/9AT?
All SMCJ78CA-E3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ78CA-E3/9AT, 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-E3/9AT part is unused and in its original packaging.
Return procedure for SMCJ78CA-E3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMCJ78CA-E3/9AT Tags
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