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Vishay General Semiconductor - Diodes Division SMBJ78AHM3_B/I
- Part No.:
- SMBJ78AHM3_B/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78AHM3_B/I.pdf
- Description:
- 600W,78V 5%,UNIDIR,SMB TVS
- Quantity:
- Payment:
- Shipping:
Inventory:9,615
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Product details
Overview
SMBJ78AHM3_B/I from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in the SMB (DO-214AA) package, designed for robust overvoltage protection of DC power rails 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, and 600 W peak pulse power rating with 10/1000 µs waveform - deployed in industrial motor drives, automotive body control modules, and telecom power supplies.
For engineers reviewing the SMBJ78AHM3_B/I datasheet, SMBJ78AHM3_B/I pinout, SMBJ78AHM3_B/I application, or SMBJ78AHM3_B/I equivalent, key selection criteria include its halogen-free RoHS-compliant construction (HM3 suffix), AEC-Q101 qualification, 150 °C max junction temperature, and verified clamping performance under repetitive surge conditions per IEC 61000-4-5.
Technical Context
This TVS diode operates as a unidirectional clamping device, leveraging an avalanche breakdown mechanism to limit transient voltages above its VWM threshold. Its low incremental surge resistance (typical <1 Ω) ensures minimal voltage overshoot during fast-rising transients up to 40 A peak, while the glass-passivated junction delivers stable leakage (<1 µA at 78 V) and long-term reliability.
The SMBJ78AHM3_B/I is rated for 100 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine) and exhibits a thermal resistance of 100 °C/W (junction-to-ambient) on standard 5.0 mm × 5.0 mm copper pads - enabling effective heat dissipation in compact PCB layouts without forced cooling.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - Maximum continuous reverse operating voltage before significant conduction begins; defines safe DC rail margin. |
| VBR (Breakdown Voltage) | 86.7–95.8 V at 1 mA - Confirmed avalanche onset range; ensures reliable triggering above nominal system voltage. |
| VC (Clamping Voltage) | 126 V at 4.8 A (10/1000 µs) - Measured limiting voltage during surge; determines protected IC's maximum stress level. |
| PPPM (Peak Pulse Power) | 600 W - Sustained energy absorption capability for standardized lightning/surge waveforms per IEC 61000-4-5. |
| IPPM (Peak Pulse Current) | 4.8 A - Peak current handled at VC; directly correlates with system-level surge immunity level. |
| TJmax | 150 °C - Maximum allowable junction temperature; supports operation in under-hood automotive and industrial enclosures. |
| Package | SMB (DO-214AA) - Surface-mount footprint (5.21 mm × 4.06 mm × 2.20 mm); compatible with automated pick-and-place and reflow. |
Pinout & Package
Package: SMB (DO-214AA), molded plastic case with matte tin-plated leads; cathode indicated by band marking on one end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or return path; completes clamping loop when transient exceeds VWM. |
| Cathode | High-side connection point | Connected to protected line (e.g., 78 V rail); polarity-sensitive - reversal prevents clamping function. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Enables compliance with IEC 61000-4-5 Level 4 (4 kV) surge testing on 48 V and 78 V DC systems. |
| AEC-Q101 qualified (HM3 suffix) | Validated for automotive applications including BCM, lighting control, and infotainment power inputs. |
| Halogen-free, RoHS-compliant | Meets IPC-1752A material declaration requirements and EU Directive 2011/65/EU Annex II updates. |
| MSL Level 1 (260 °C peak) | Supports single-reflow assembly without moisture sensitivity concerns; no baking required pre-assembly. |
| Low clamping ratio (VC/VBR ≈ 1.32) | Minimizes overvoltage stress on downstream MOSFETs or regulators during ESD or load-dump events. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC I/O Protection |
|---|---|
|
Use Scenario: Protects 78 V auxiliary power rail in BCM against load dump transients (ISO 7637-2 Pulse 5a). IC Role / Device Role / Timing Role: Unidirectional TVS clamping device placed between input rail and ground. Use Value: Limits transient voltage to ≤126 V, preventing damage to 100 V-rated DC-DC controllers and CAN transceivers. |
Use Scenario: Shields 24–75 V digital I/O channels in programmable logic controllers from inductive switching spikes. IC Role / Device Role / Timing Role: Standoff-clamp protector on field-side signal lines interfacing solenoids or relays. Use Value: Responds in <1 ps to clamp 1 kV/µs transients, preserving signal integrity and reducing false triggering. |
| Telecom Power Supply Input | Motor Drive DC Bus Protection |
|
Use Scenario: Safeguards primary-side 78 V DC bus in telecom rectifier modules against lightning-induced surges. IC Role / Device Role / Timing Role: Primary overvoltage suppression element upstream of bulk capacitors and PFC stage. Use Value: Absorbs 600 W pulses without degradation, maintaining system uptime during outdoor cabinet surges. |
Use Scenario: Guards gate driver supply rails in 72–80 V BLDC motor inverters against cross-talk and flyback spikes. IC Role / Device Role / Timing Role: Localized clamping device adjacent to high-side gate drivers and bootstrap circuits. Use Value: Prevents latch-up in 100 V logic-level MOSFETs by holding gate-source voltage within safe limits. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78AHE3_B/I | Same electrical specs; RoHS-compliant but not halogen-free (E3 vs HM3). | Lacks halogen-free certification; unsuitable for automotive OEMs requiring IPC-1752A full material disclosure. | Select when halogen content is not regulated and cost optimization is prioritized. |
| SMAJ78A-M3/5B | Lower PPPM (400 W), larger SMA package (DO-214AC), same VWM/VC ratings. | Reduced surge margin; requires larger PCB area and lower thermal performance (RθJA = 140 °C/W). | Choose only if legacy SMA footprint compatibility is mandatory and 400 W suffices. |
Compared with SMBJ78AHM3_B/I, the E3 variant trades halogen-free compliance for lower cost, while the SMAJ78A-M3/5B sacrifices 33 % peak power handling and thermal efficiency for backward package compatibility - making SMBJ78AHM3_B/I optimal for new AEC-Q101–mandated designs demanding full environmental compliance and highest surge resilience.
Availability
SMBJ78AHM3_B/I is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, and telecom infrastructure requiring stable component supply with full halogen-free and AEC-Q101 assurance.
Supply support for SMBJ78AHM3_B/I 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, MOSFETs, optoelectronics, and passive components with emphasis on reliability and automotive-grade validation.
The SMBJ series is engineered for high-energy transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where robustness, repeatability, and regulatory compliance are critical.
FAQ
What is the clamping voltage of SMBJ78AHM3_B/I at its rated peak pulse current?
The SMBJ78AHM3_B/I has a maximum clamping voltage (VC) of 126 V when subjected to its specified peak pulse current of 4.8 A using the 10/1000 µs waveform. This value is measured per JEDEC standards and guarantees predictable overvoltage limiting behavior during surge events - essential for protecting downstream 100 V-rated components in the same circuit as SMBJ78AHM3_B/I.
Is SMBJ78AHM3_B/I suitable for automotive applications?
Yes, SMBJ78AHM3_B/I is AEC-Q101 qualified and carries the HM3 suffix denoting halogen-free, RoHS-compliant construction - meeting stringent automotive requirements for under-hood and body electronics. Its 150 °C junction rating, MSL Level 1 reflow compatibility, and validated surge performance make it appropriate for BCM, lighting control, and infotainment power stages where SMBJ78AHM3_B/I is deployed.
How does the HM3 suffix differ from the E3 suffix in Vishay SMBJ part numbers?
The HM3 suffix indicates halogen-free, RoHS-compliant, and AEC-Q101–qualified construction, whereas E3 denotes RoHS-compliant and commercial-grade only (no halogen-free claim or automotive qualification). For SMBJ78AHM3_B/I, HM3 ensures full material compliance for Tier 1 automotive supply chains, while SMBJ78AHE3_B/I lacks both halogen-free certification and AEC-Q101 validation - a critical distinction when specifying SMBJ78AHM3_B/I for OEM programs.
What is the thermal resistance of SMBJ78AHM3_B/I, and how does it affect layout design?
SMBJ78AHM3_B/I has a typical junction-to-ambient thermal resistance (RθJA) of 100 °C/W when mounted on 5.0 mm × 5.0 mm copper pads per terminal. This value assumes standard FR-4 PCB with minimum recommended pad layout; designers must allocate adequate copper area and avoid thermal bottlenecks to maintain TJ ≤ 150 °C during repetitive surges - a key constraint for sustained reliability of SMBJ78AHM3_B/I in high-duty-cycle applications.
Can SMBJ78AHM3_B/I be used in bidirectional protection circuits?
No, SMBJ78AHM3_B/I is a unidirectional TVS diode - identified by the "A" suffix and cathode band marking - and conducts only in reverse bias above VBR. For bidirectional protection, Vishay specifies the "CA" suffix (e.g., SMBJ78CA). Using SMBJ78AHM3_B/I in AC or symmetrical transient scenarios would result in forward conduction during negative excursions, potentially damaging the device or failing to protect - so SMBJ78AHM3_B/I must be applied strictly in DC-polarized configurations.
SMBJ78AHM3_B/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- 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)
SMBJ78AHM3_B/I FAQ
1.How can I place an order for SMBJ78AHM3_B/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78AHM3_B/I 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 SMBJ78AHM3_B/I reliable?
The price and inventory of SMBJ78AHM3_B/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78AHM3_B/I is usually 5 days.
3.What payment methods are accepted for SMBJ78AHM3_B/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78AHM3_B/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78AHM3_B/I?
SMBJ78AHM3_B/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78AHM3_B/I 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 SMBJ78AHM3_B/I?
For technical support, including SMBJ78AHM3_B/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78AHM3_B/I requirements.
6.How does Aetrix verify that SMBJ78AHM3_B/I is sourced from the original manufacturer or authorized distributors?
All SMBJ78AHM3_B/I 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 SMBJ78AHM3_B/I meets industry standards.
7.What is the process for return or replacement of SMBJ78AHM3_B/I?
All SMBJ78AHM3_B/I units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78AHM3_B/I, 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 SMBJ78AHM3_B/I part is unused and in its original packaging.
Return procedure for SMBJ78AHM3_B/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78AHM3_B/I Tags
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