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Vishay General Semiconductor - Diodes Division SMBJ78CAHM3_B/H
- Part No.:
- SMBJ78CAHM3_B/H
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78CAHM3_B/H.pdf
- Description:
- 600W,78V 5%,BIDIR,SMB TVS
- Quantity:
- Payment:
- Shipping:
Inventory:4,146
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Product details
Overview
SMBJ78CAHM3_B/H from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, designed for clamping voltage transients on power and signal lines. It features a 78 V stand-off voltage (VWM), 86.7–95.8 V breakdown voltage (VBR) at 1 mA, 126 V maximum clamping voltage (VC) at 4.8 A peak pulse current (IPPM), and 600 W peak pulse power (10/1000 µs waveform), used to protect MOSFETs, ICs, and sensor interfaces in industrial power supplies and telecom line cards.
For engineers reviewing the SMBJ78CAHM3_B/H datasheet, SMBJ78CAHM3_B/H pinout, SMBJ78CAHM3_B/H application, or SMBJ78CAHM3_B/H equivalent, this page delivers verified electrical specs, bidirectional clamping behavior, thermal derating curves, JEDEC-compliant SMB package dimensions, and AEC-Q101-qualified halogen-free alternatives - all critical for surge protection layout validation and automotive-grade BOM selection.
Technical Context
This device operates as a bidirectional avalanche diode with symmetrical clamping in both polarities, enabling transient suppression without polarity sensitivity on AC-coupled or floating lines. Its 126 V clamping voltage at 4.8 A ensures robust overvoltage limiting during 10/1000 µs surges while maintaining low incremental surge resistance and sub-nanosecond response time.
The SMBJ78CAHM3_B/H uses glass-passivated junction construction, meets MSL Level 1 per J-STD-020 (peak reflow 260 °C), and is halogen-free and RoHS-compliant per Vishay HM3 suffix designation. Its thermal resistance (RθJA = 100 °C/W) and junction temperature range (–55 °C to +150 °C) support operation in high-ambient industrial environments with minimal heatsinking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - Maximum continuous reverse voltage before significant leakage; defines operating margin below clamping threshold. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Guaranteed avalanche initiation range; ensures consistent turn-on across production lots. |
| VC (Clamping Voltage) | 126 V at IPPM = 4.8 A - Peak voltage seen by protected circuit during 10/1000 µs surge; determines downstream component stress. |
| PPPM (Peak Pulse Power) | 600 W (10/1000 µs) - Surge energy handling capacity; supports IEC 61000-4-5 Level 4 compliance with proper PCB layout. |
| ID (Reverse Leakage) | 1.0 µA max at VWM - Minimal standby power loss and signal integrity impact on high-impedance nodes. |
| TJ max | +150 °C - Enables use in under-hood automotive modules or enclosed industrial enclosures without active cooling. |
| Package | SMB (DO-214AA) - Standardized 2-pin SMD outline with 5.0 mm × 3.94 mm footprint; compatible with automated pick-and-place and reflow. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, bidirectional configuration with no polarity marking - both terminals are electrically symmetrical.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Transient conduction path | Identical terminals; conducts in either direction when voltage exceeds |VBR| - eliminates orientation concerns during placement. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC lines, differential buses, or ungrounded sensor outputs without external polarity management. |
| 600 W peak pulse power (10/1000 µs) | Supports EN 61000-4-5 4 kV surge testing with standard PCB copper pad layout (0.2" × 0.2") without derating. |
| Halogen-free & RoHS-compliant (HM3 suffix) | Fulfills IPC-1752A material declaration requirements and EU RoHS Directive 2011/65/EU for green manufacturing. |
| MSL Level 1 rating | Allows unlimited floor life and standard reflow profile (peak 260 °C) without dry-pack or baking preconditioning. |
| AEC-Q101 qualified option available | HM3 variant supports automotive subsystems requiring qualification per JESD22-A108; base P/NHM3_X denotes qualified revision. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) CAN Bus Lines |
|---|---|
|
Use Scenario: Suppresses load-dump and jump-start transients on 24 V DC input rails feeding switching regulators and microcontrollers. IC Role / Device Role: Primary clamping element placed upstream of input filter capacitors and DC-DC controllers. Use Value: Limits rail voltage to ≤126 V during 100 ms, 35 V load dump events, preventing overvoltage failure of 36 V-rated input stages. |
Use Scenario: Protects CANH/CANL differential pair against ESD and coupled transients in vehicle door modules and lighting ECUs. IC Role / Device Role: Bidirectional TVS placed across differential bus lines, referenced to chassis ground via low-inductance layout. Use Value: Clamps ±25 kV contact ESD (IEC 61000-4-2) and 42 V inductive spikes to safe levels (<15 V differential swing), preserving CAN transceiver integrity. |
| Telecom Line Card Surge Protection | Industrial Sensor Signal Conditioning Interface |
|
Use Scenario: Shields Ethernet PHY front-end and PoE interface components from lightning-induced surges on RJ45 ports. IC Role / Device Role: Secondary-level TVS mounted adjacent to magnetics, complementing primary gas discharge tube (GDT) protection. Use Value: Responds within <1 ns to clamp residual transients to <130 V after GDT crowbarring, protecting 100BASE-TX transformers rated for 150 V isolation. |
Use Scenario: Guards analog output lines (e.g., 4–20 mA, 0–10 V) of pressure/temperature transmitters exposed to field wiring faults. IC Role / Device Role: Low-leakage (1 µA) bidirectional suppressor placed at connector entry point, before signal conditioning op-amps. Use Value: Maintains signal accuracy with <1 µA leakage at 78 V, while clamping 1 kV/µs fast transients to <130 V to prevent op-amp latch-up or ADC saturation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78CAHE3_B/H | Same electrical specs and SMB package; RoHS-compliant but not halogen-free (E3 vs HM3). | Preferred for commercial-grade systems where halogen content is unrestricted and cost is prioritized. | Select when halogen-free certification is not required and procurement favors standard E3 suffix inventory. |
| SMAJ78CAHM3 | Lower PPPM (400 W vs 600 W); SMA package (smaller footprint, higher RθJA = 140 °C/W). | Suitable only for lower-energy transients or space-constrained designs with adequate thermal relief. | Choose only if board area is critical and surge threat level is limited to IEC 61000-4-2 Level 3 (±8 kV contact). |
Compared with SMBJ78CAHM3_B/H, the HE3 variant trades halogen-free compliance for broader distributor availability, while the SMAJ78CAHM3 reduces surge margin and thermal performance to fit tighter layouts - neither offers drop-in replacement capability without layout or derating review.
Availability
SMBJ78CAHM3_B/H is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, telecom line cards, and sensor interface circuits requiring stable component supply with halogen-free and AEC-Q101-qualified traceability.
Supply support for SMBJ78CAHM3_B/H 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, and protection devices with emphasis on reliability, power efficiency, and automotive qualification.
The SMBJ series was developed for high-energy transient suppression in harsh environments, targeting industrial automation, automotive subsystems, and infrastructure equipment where robustness and long-term stability are mandatory.
FAQ
What is the clamping voltage of SMBJ78CAHM3_B/H at its rated peak pulse current?
The SMBJ78CAHM3_B/H has a maximum clamping voltage (VC) of 126 V at its specified peak pulse current (IPPM) of 4.8 A under a 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees the upper voltage limit imposed on protected circuitry during standardized surge events - critical for validating downstream component voltage ratings against IEC 61000-4-5 compliance requirements. The SMBJ78CAHM3_B/H maintains this clamping performance across its full operating temperature range.
Is SMBJ78CAHM3_B/H suitable for automotive applications?
Yes - the HM3 suffix indicates halogen-free and RoHS-compliant construction, and Vishay offers AEC-Q101-qualified versions under ordering codes like SMBJ78CAHM3_B/I (where "_B/I" denotes qualified revision). While SMBJ78CAHM3_B/H itself is commercial-grade, its design basis, thermal specs (TJ max = +150 °C), and mechanical robustness align with automotive subsystem requirements; actual qualification status must be confirmed via the specific revision code and Vishay's official AEC-Q101 certificate for the exact P/N. SMBJ78CAHM3_B/H serves as the foundation for qualified variants.
How does the bidirectional nature of SMBJ78CAHM3_B/H affect PCB layout?
The SMBJ78CAHM3_B/H has no polarity marking and identical electrical behavior in both directions, so PCB layout requires no anode/cathode orientation check - the device can be placed in either direction across protected lines. This simplifies automated assembly and eliminates risk of reverse installation. Layout best practices still apply: short, low-inductance traces to the protected node, symmetric grounding to minimize loop area, and adherence to Vishay's recommended 0.2" × 0.2" copper pads per terminal to sustain 600 W pulse power without thermal runaway. SMBJ78CAHM3_B/H benefits directly from this symmetry in AC or floating applications.
What is the maximum reverse leakage current for SMBJ78CAHM3_B/H at its stand-off voltage?
The SMBJ78CAHM3_B/H exhibits a maximum reverse leakage current (ID) of 1.0 µA at its rated stand-off voltage (VWM) of 78 V and TA = 25 °C. This ultra-low leakage preserves signal integrity on high-impedance sensor outputs and minimizes standby power loss in battery-operated systems. Leakage remains below 5 µA up to +85 °C per Vishay's derating curves, making SMBJ78CAHM3_B/H suitable for precision analog interfaces where leakage-induced offset or drift must be avoided - a key differentiator versus higher-leakage TVS alternatives.
Does SMBJ78CAHM3_B/H require heatsinking in typical applications?
No external heatsink is required for SMBJ78CAHM3_B/H in standard surge protection applications because its 600 W peak pulse power is rated with 0.2" × 0.2" copper pads per terminal - sufficient for transient dissipation. Its thermal resistance (RθJA = 100 °C/W) and 150 °C max junction temperature allow reliable operation at +85 °C ambient with no additional thermal relief. Continuous power dissipation is limited to 5.0 W, but TVS devices only conduct during transient events (ms duration), so steady-state heating is negligible. SMBJ78CAHM3_B/H relies on PCB copper as its thermal path, not external heatsinks.
SMBJ78CAHM3_B/H Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Bulk
- 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):
- 4.8A
- Power - Peak Pulse:
- 600W
- 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-214AA (SMB)
SMBJ78CAHM3_B/H FAQ
1.How can I place an order for SMBJ78CAHM3_B/H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78CAHM3_B/H 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 SMBJ78CAHM3_B/H reliable?
The price and inventory of SMBJ78CAHM3_B/H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78CAHM3_B/H is usually 5 days.
3.What payment methods are accepted for SMBJ78CAHM3_B/H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78CAHM3_B/H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78CAHM3_B/H?
SMBJ78CAHM3_B/H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78CAHM3_B/H 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 SMBJ78CAHM3_B/H?
For technical support, including SMBJ78CAHM3_B/H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78CAHM3_B/H requirements.
6.How does Aetrix verify that SMBJ78CAHM3_B/H is sourced from the original manufacturer or authorized distributors?
All SMBJ78CAHM3_B/H 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 SMBJ78CAHM3_B/H meets industry standards.
7.What is the process for return or replacement of SMBJ78CAHM3_B/H?
All SMBJ78CAHM3_B/H units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78CAHM3_B/H, 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 SMBJ78CAHM3_B/H part is unused and in its original packaging.
Return procedure for SMBJ78CAHM3_B/H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78CAHM3_B/H Tags
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