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Vishay General Semiconductor - Diodes Division SMCG78CA-E3/9AT
- Part No.:
- SMCG78CA-E3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-215AB, SMC Gull Wing
- Datasheet:
-
SMCG78CA-E3/9AT.pdf
- Description:
- TVS DIODE 78VWM 126VC DO215AB
- Quantity:
- Payment:
- Shipping:
Inventory:3,957
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Product details
Overview
SMCG78CA-E3/9AT from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in the SMCG (DO-215AB) surface-mount package, designed for robust overvoltage protection of sensitive electronics. It features a 78 V stand-off voltage (VWM), 126 V maximum clamping voltage (VC) at 11.9 A peak pulse current (IPPM), and 1500 W peak pulse power dissipation (PPPM) with a 10/1000 µs waveform - deployed in automotive sensor signal lines, industrial I/O interfaces, and telecom power rails.
For engineers reviewing the SMCG78CA-E3/9AT datasheet, SMCG78CA-E3/9AT pinout, SMCG78CA-E3/9AT application, or SMCG78CA-E3/9AT equivalent, this page delivers verified electrical specs, AEC-Q101 qualification status, thermal resistance (RθJA = 75 °C/W), DO-215AB mechanical dimensions, and direct alternatives for bidirectional TVS selection in high-reliability designs.
Technical Context
The SMCG78CA-E3/9AT operates as a bidirectional avalanche diode, symmetrically clamping voltage transients in both polarities without polarity marking. Its glass-passivated junction ensures stable breakdown behavior and low incremental surge resistance, enabling sub-nanosecond response to ESD and lightning-induced surges.
Rated for -55 °C to +150 °C junction temperature, it meets MSL Level 1 per J-STD-020 and is AEC-Q101 qualified - confirming suitability for under-hood automotive environments. The device draws ≤1.0 µA reverse leakage at 78 V (VWM), with breakdown voltage (VBR) specified between 86.7 V and 95.8 V at 1 mA test current.
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 - defines guaranteed breakdown window for design margining |
| VC @ IPPM | 126 V at 11.9 A - clamping voltage during 10/1000 µs surge, limiting stress on downstream ICs |
| PPPM | 1500 W - peak transient energy handling capacity under standardized surge waveform |
| RθJA | 75 °C/W - thermal resistance from junction to ambient on 8 mm × 8 mm copper pads, critical for power derating |
| TJ max | +150 °C - maximum junction temperature, supporting operation in engine control units and industrial drives |
| AEC-Q101 | Qualified - validated for automotive-grade reliability including temperature cycling and HTRB |
Pinout & Package
Package: SMCG (DO-215AB) - low-profile, gull-wing surface-mount case with matte tin-plated leads, compliant with J-STD-002 solderability and JESD22-B102 whisker testing. No polarity marking for bidirectional configuration.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry (negative polarity) | One terminal of symmetrical avalanche junction; accepts surge current in either direction |
| Cathode | Transient current entry (positive polarity) | Second terminal of symmetrical junction; identical electrical role to Anode in bidirectional mode |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity concerns |
| AEC-Q101 qualification | Validates reliability for automotive applications including ADAS camera modules and body control units |
| Low RθJA (75 °C/W) | Supports sustained 6.5 W power dissipation at TA = 50 °C with standard PCB copper area |
| MSL Level 1 rating | Permits unlimited floor life and reflow at 260 °C peak, simplifying SMT manufacturing |
| Glass-passivated junction | Ensures stable VBR over lifetime and immunity to humidity-induced parameter drift |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting CAN/FlexRay transceiver inputs and analog sensor outputs (e.g., pressure, temperature) from load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed directly at connector interface to shunt transients before reaching signal conditioning circuitry. Use Value: Limits voltage seen by protected ICs to ≤126 V during 1500 W surges, preserving signal integrity and preventing latch-up in 3.3 V/5 V microcontrollers. | Use Scenario: Safeguarding digital input channels on programmable logic controllers exposed to inductive switching noise from solenoids and contactors. IC Role / Device Role / Timing Role: Fast-response TVS absorbing repetitive 10/1000 µs transients induced by relay coil de-energization on 24 V DC inputs. Use Value: With 1.0 µA leakage at 78 V, it avoids false triggering while clamping spikes within 1 ns - maintaining input logic state fidelity. |
| Telecom Power Rail Protection | Consumer USB Interface Protection |
Use Scenario: Guarding 48 V PoE (Power over Ethernet) data line receivers against lightning-induced common-mode surges on outdoor network equipment. IC Role / Device Role / Timing Role: Bidirectional TVS placed across differential pairs to clamp mode-converted surges without disrupting DC bias or signal swing. Use Value: Symmetric 86.7–95.8 V VBR ensures balanced clamping on both lines, preventing skew and maintaining IEEE 802.3af compliance. | Use Scenario: Shielding USB 2.0 D+/D− lines in portable devices from ESD events exceeding ±15 kV (air discharge) per IEC 61000-4-2. IC Role / Device Role / Timing Role: Low-capacitance transient suppressor mounted adjacent to USB connector to intercept ESD before reaching PHY IC. Use Value: Sub-1 ns response time and 126 V VC limit transient overshoot below USB PHY damage threshold, even at 30 A contact discharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ78CA | Same VWM (78 V) and VC (126 V), but lower PPPM (400 W) and DO-214AC (SMA) package | Limited to lower-energy transients; less suitable for automotive load dump where 1500 W capability is required | Select SMAJ78CA only when board space constraints favor SMA footprint and surge energy is <400 W |
| 1.5KE78CA | Higher PPPM (1500 W), same VWM/VC, but axial-leaded DO-15 package and higher RθJA (~50 °C/W on minimal pad) | Not surface-mountable; requires through-hole assembly and larger PCB real estate | Choose 1.5KE78CA only for prototyping or legacy through-hole designs where rework tolerance outweighs SMT efficiency |
Compared with SMAJ78CA and 1.5KE78CA, the SMCG78CA-E3/9AT uniquely combines AEC-Q101 qualification, DO-215AB's low-profile gull-wing geometry, and full 1500 W surge rating - making it the preferred choice for production automotive and industrial SMT assemblies requiring zero layout change and verified reliability.
Availability
SMCG78CA-E3/9AT is available at Aetrix Electronics and suitable for automotive sensor modules, industrial PLC I/O cards, and telecom power-over-Ethernet equipment requiring stable component supply and long-term lifecycle support.
Supply support for SMCG78CA-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, power efficiency, and automotive-grade qualification.
The SMCG series is part of Vishay's TRANSZORB® TVS platform, engineered specifically for high-energy transient suppression in harsh environments - targeting automotive, industrial automation, and infrastructure applications demanding AEC-Q101 validation and MSL Level 1 process compatibility.
FAQ
What is the clamping voltage of SMCG78CA-E3/9AT at its rated peak pulse current?
The SMCG78CA-E3/9AT has a maximum clamping voltage (VC) of 126 V when subjected to its rated peak pulse current (IPPM) of 11.9 A under a 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 standards and ensures downstream components experience no more than 126 V during surge events - a critical parameter for protecting 3.3 V, 5 V, or 24 V logic and interface ICs. The SMCG78CA-E3/9AT maintains this clamping performance across its full operating temperature range (-55 °C to +150 °C).
Is SMCG78CA-E3/9AT suitable for automotive applications?
Yes, the SMCG78CA-E3/9AT is AEC-Q101 qualified and rated for junction temperatures up to +150 °C, making it suitable for under-hood and chassis-mounted automotive systems. Its bidirectional architecture protects differential sensor signals (e.g., wheel speed, pressure) from both positive and negative transients, and its MSL Level 1 rating supports lead-free reflow without moisture sensitivity concerns. The SMCG78CA-E3/9AT is explicitly listed in Vishay's automotive-grade product portfolio for use in body control modules, ADAS interfaces, and powertrain subsystems.
What does the "CA" suffix indicate in SMCG78CA-E3/9AT?
The "CA" suffix in SMCG78CA-E3/9AT denotes a bidirectional transient voltage suppressor configuration, meaning the device provides symmetrical clamping in both forward and reverse directions - with no cathode band marking. This differs from unidirectional variants (e.g., SMCG78A), which have polarity-sensitive operation and a visible cathode band. The CA version is selected for AC-coupled lines, floating grounds, or differential signaling where polarity reversal must be handled without external circuit changes. The SMCG78CA-E3/9AT's VBR is specified identically in both directions (86.7–95.8 V).
What is the thermal resistance of SMCG78CA-E3/9AT, and how does it affect layout?
The SMCG78CA-E3/9AT has a typical junction-to-ambient thermal resistance (RθJA) of 75 °C/W when mounted on 0.31" × 0.31" (8.0 mm × 8.0 mm) copper pads per terminal. This value assumes minimum recommended pad layout per Vishay's datasheet - underscoring the need for adequate copper area to sustain its 6.5 W steady-state power dissipation at TA = 50 °C. Reducing pad size increases RθJA, accelerating thermal derating; thus, the SMCG78CA-E3/9AT's layout must follow DO-215AB mounting guidelines to avoid premature thermal failure during repeated surge events.
How does SMCG78CA-E3/9AT differ from SMCG78A-E3/9AT?
The SMCG78CA-E3/9AT is bidirectional with symmetrical clamping and no polarity marking, whereas SMCG78A-E3/9AT is unidirectional and features a cathode band. Electrically, SMCG78CA-E3/9AT has identical VWM (78 V) and VC (126 V), but adds reverse conduction capability - critical for protecting AC signals or floating nodes. SMCG78A-E3/9AT supports higher IFSM (200 A) and includes forward voltage (VF = 3.5 V at 100 A), which is irrelevant for the CA variant. For designs requiring polarity-agnostic protection - such as RS-485 buses or automotive LIN networks - the SMCG78CA-E3/9AT is the appropriate selection.
SMCG78CA-E3/9AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-215AB, SMC Gull Wing
- 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 (SMCG)
SMCG78CA-E3/9AT FAQ
1.How can I place an order for SMCG78CA-E3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCG78CA-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 SMCG78CA-E3/9AT reliable?
The price and inventory of SMCG78CA-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 SMCG78CA-E3/9AT is usually 5 days.
3.What payment methods are accepted for SMCG78CA-E3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCG78CA-E3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCG78CA-E3/9AT?
SMCG78CA-E3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCG78CA-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 SMCG78CA-E3/9AT?
For technical support, including SMCG78CA-E3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCG78CA-E3/9AT requirements.
6.How does Aetrix verify that SMCG78CA-E3/9AT is sourced from the original manufacturer or authorized distributors?
All SMCG78CA-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 SMCG78CA-E3/9AT meets industry standards.
7.What is the process for return or replacement of SMCG78CA-E3/9AT?
All SMCG78CA-E3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with SMCG78CA-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 SMCG78CA-E3/9AT part is unused and in its original packaging.
Return procedure for SMCG78CA-E3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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