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Vishay General Semiconductor - Diodes Division SMBJ78C-E3/5B
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- Part No.:
- SMBJ78C-E3/5B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78C-E3/5B.pdf
- Description:
- TVS DIODE 78VWM 139VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:7,204
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Product details
Overview
SMBJ78C-E3/5B from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, designed for robust overvoltage protection of sensitive electronics. It features a 78 V standoff voltage (VWM), 86.7–95.8 V breakdown range (VBR at 1 mA), 126 V maximum clamping voltage (VC) at 4.8 A peak pulse current, and 600 W peak pulse power rating with 10/1000 µs waveform - deployed on power rails and signal lines in industrial motor drives.
For engineers reviewing the SMBJ78C-E3/5B datasheet, SMBJ78C-E3/5B pinout, SMBJ78C-E3/5B application, or SMBJ78C-E3/5B equivalent, key selection criteria include clamping performance under 4.8 A surge, thermal resistance (RθJA = 100 °C/W), unidirectional polarity marking, RoHS-compliant matte tin plating, and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: when transient voltage exceeds VBR, it avalanches into low-impedance conduction to divert surge current away from downstream ICs or MOSFETs. Its glass-passivated junction ensures stable breakdown characteristics and fast response time (<1 ps), while the SMB package supports high surge current handling without thermal runaway under repetitive 0.01% duty cycle conditions.
The device is rated for -55 °C to +150 °C operating junction temperature, meets MSL Level 1 per J-STD-020 (peak reflow 260 °C), and exhibits 0.106 %/°C temperature coefficient of VBR. It is not AEC-Q101 qualified (suffix lacks HE3/HM3), and its unidirectional configuration requires cathode-band orientation during PCB layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - maximum continuous reverse voltage before significant leakage; defines safe operating margin below clamping threshold |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - guaranteed avalanche initiation range; ensures predictable turn-on during transients |
| VC (Clamping Voltage) | 126 V at IPPM = 4.8 A - peak voltage seen by protected circuit during 10/1000 µs surge; limits stress on downstream components |
| PPPM (Peak Pulse Power) | 600 W - maximum non-repetitive surge energy absorption capability under standardized 10/1000 µs waveform |
| IPPM (Peak Pulse Current) | 4.8 A - peak current the device safely clamps at VC; determines minimum trace width and fuse coordination |
| RθJA (Junction-to-Ambient) | 100 °C/W - thermal resistance with standard 0.2" × 0.2" copper pads; informs derating above 25 °C ambient |
| Leakage Current (ID) | 1.0 µA max at VWM - negligible standby power loss and signal integrity impact in high-impedance circuits |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, molded plastic case with matte tin-plated leads. Cathode identified by a band on one end; anode is unmarked. Meets UL 94 V-0 flammability rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient current sink node | Connected to protected line (e.g., VIN rail); conducts surge current to ground when V > VBR |
| Anode (unbanded end) | Reference/return path | Typically tied to system ground or low-impedance return plane; completes clamping current path |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Enables protection against IEC 61000-4-5 Level 4 surges (4 kV line-earth) without external series impedance |
| Low incremental surge resistance | Minimizes VC overshoot during fast-rising transients (<1 ns rise time), improving clamping fidelity |
| Glass passivated junction | Ensures long-term stability of VBR and leakage across temperature and humidity stress |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow without baking; compatible with high-volume SMT assembly |
| RoHS-compliant, commercial grade (E3 suffix) | Meets global environmental regulations; no halogen restrictions or automotive qualification required |
Applications
| Industrial Motor Drive Power Supply | Automotive Body Control Module (BCM) Input Protection |
|---|---|
Use Scenario: Protecting 78 V nominal DC bus against switching transients from relay coils and contactor bounce in factory automation systems. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed between VBUS and chassis ground, clamping spikes within 126 V to safeguard DC-DC converters and gate drivers. Use Value: Prevents latch-up or overvoltage failure in 80 V-rated MOSFETs and isolated error amplifiers during 4.8 A inductive kick events. |
Use Scenario: Safeguarding 12 V–78 V battery-supplied inputs in BCMs exposed to load dump and jump-start surges per ISO 7637-2. IC Role / Device Role / Timing Role: Primary front-end clamp on main power input, coordinated with upstream fuses and secondary LC filtering. Use Value: Limits peak voltage to 126 V during 10/1000 µs load dump pulses, enabling use of cost-optimized 150 V-rated input capacitors and regulators. |
| Telecom Remote Radio Unit (RRU) DC Feed Line | Programmable Logic Controller (PLC) Analog Input Protection |
Use Scenario: Protecting 48–78 V DC power feed lines in outdoor RRUs from lightning-induced surges coupled via tower grounding paths. IC Role / Device Role / Timing Role: First-stage TVS on PoE-like DC feed, mounted directly at connector entry point with minimal trace inductance. Use Value: Clamps induced surges to ≤126 V before they reach DC-DC isolation stages, preserving 150 V isolation barrier integrity. |
Use Scenario: Shielding 4–20 mA analog input channels in industrial PLCs from field wiring transients caused by nearby AC motor switching. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) unidirectional TVS placed across input terminals, referenced to signal ground. Use Value: Maintains <1 µA leakage at 78 V, preventing measurement offset drift while suppressing >1 kV transients per IEC 61000-4-4. |
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-E3/5B | Same VWM (78 V), identical VBR and VC specs; differs only in marking code (NT vs. NT-C), indicating same electrical binning | No functional difference; both are unidirectional, E3 RoHS-compliant, SMB-packaged TVS diodes | Select SMBJ78C-E3/5B if manufacturer-marked "C" variant is specified in legacy BOM or test documentation |
| SMCJ78A-E3/57T | Higher package thermal mass (SMC/DO-214AB); RθJA = 40 °C/W vs. 100 °C/W; same VWM/VC but 1500 W PPPM | Used where higher surge repetition rate or longer pulse duration (e.g., 8/20 µs) is expected; requires larger PCB footprint | Choose SMCJ78A-E3/57T only when 600 W is insufficient and board space allows DO-214AB footprint |
Compared with SMBJ78A-E3/5B, SMBJ78C-E3/5B offers identical protection performance in the same SMB footprint; versus SMCJ78A-E3/57T, it trades higher surge capacity for compact size and lower thermal resistance in high-density layouts.
Availability
SMBJ78C-E3/5B is available at Aetrix Electronics and suitable for industrial motor drives, telecom remote radio units, programmable logic controllers, and automotive body control modules requiring stable component supply and RoHS-compliant transient protection.
Supply support for SMBJ78C-E3/5B 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 optoelectronics with emphasis on reliability and application-specific performance.
The SMBJ series is engineered for high-energy transient suppression in space-constrained, high-reliability power and signal line applications - balancing clamping precision, surge robustness, and manufacturability in standard SMT packages.
FAQ
What is the clamping voltage of SMBJ78C-E3/5B at its rated peak pulse current?
The SMBJ78C-E3/5B has a maximum clamping voltage (VC) of 126 V at its rated peak pulse current (IPPM) of 4.8 A, measured under the standardized 10/1000 µs double-exponential waveform. This value defines the highest voltage imposed on the protected circuit during a worst-case surge event and is critical for ensuring downstream components remain within their absolute maximum ratings. The SMBJ78C-E3/5B maintains this clamping performance across its full operating temperature range.
Is SMBJ78C-E3/5B bidirectional or unidirectional?
SMBJ78C-E3/5B is a unidirectional transient voltage suppressor, indicated by the "A" suffix (not "CA") and the cathode band marking on the SMB package. It conducts only in reverse bias above VBR, making it suitable for DC power line protection where polarity is fixed. Bidirectional variants (e.g., SMBJ78CA) would lack the cathode band and conduct symmetrically in both directions - a distinction clearly defined in the Vishay SMBJ datasheet for SMBJ78C-E3/5B.
Does SMBJ78C-E3/5B meet automotive qualification standards?
No, SMBJ78C-E3/5B is not AEC-Q101 qualified. Its "E3" suffix denotes RoHS-compliant commercial-grade construction, whereas automotive-qualified versions carry "HE3" or "HM3" suffixes (e.g., SMBJ78AHE3_B). The SMBJ78C-E3/5B datasheet does not list AEC-Q101 testing or qualification data, and its ordering information contains no automotive-grade packaging codes. For automotive applications, engineers must select explicitly qualified variants rather than relying on SMBJ78C-E3/5B.
What is the thermal resistance of SMBJ78C-E3/5B, and how does it affect layout?
The SMBJ78C-E3/5B has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value assumes minimal copper area and dictates derating of peak pulse power above 25 °C ambient temperature - for example, at 85 °C ambient, usable PPPM drops to ~360 W. To maintain full 600 W rating, designers should maximize copper pour area and consider thermal vias beneath the SMB pads. The SMBJ78C-E3/5B thermal performance is validated per JEDEC standards.
How does the leakage current of SMBJ78C-E3/5B impact high-impedance analog circuits?
SMBJ78C-E3/5B exhibits a maximum reverse leakage current (ID) of 1.0 µA at its 78 V stand-off voltage (VWM), measured at 25 °C. This ultra-low leakage ensures minimal loading on high-impedance nodes - such as sensor bias networks or precision reference dividers - where even nanoamp-level currents could induce measurable offset errors. At elevated temperatures, leakage increases predictably (per Arrhenius behavior), remaining below 10 µA up to 125 °C. The SMBJ78C-E3/5B leakage specification is verified per ANSI/IEEE C62.35 and confirmed in Vishay's production testing.
SMBJ78C-E3/5B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 78V
- Voltage - Breakdown (Min):
- 86.7V
- Voltage - Clamping (Max) @ Ipp:
- 139V
- Current - Peak Pulse (10/1000µs):
- 4.3A
- Power - Peak Pulse:
- 600W
- 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-214AA (SMBJ)
SMBJ78C-E3/5B FAQ
1.How can I place an order for SMBJ78C-E3/5B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78C-E3/5B 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 SMBJ78C-E3/5B reliable?
The price and inventory of SMBJ78C-E3/5B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78C-E3/5B is usually 5 days.
3.What payment methods are accepted for SMBJ78C-E3/5B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78C-E3/5B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78C-E3/5B?
SMBJ78C-E3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78C-E3/5B 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 SMBJ78C-E3/5B?
For technical support, including SMBJ78C-E3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78C-E3/5B requirements.
6.How does Aetrix verify that SMBJ78C-E3/5B is sourced from the original manufacturer or authorized distributors?
All SMBJ78C-E3/5B 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 SMBJ78C-E3/5B meets industry standards.
7.What is the process for return or replacement of SMBJ78C-E3/5B?
All SMBJ78C-E3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78C-E3/5B, 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 SMBJ78C-E3/5B part is unused and in its original packaging.
Return procedure for SMBJ78C-E3/5B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78C-E3/5B Tags
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