My Inquiry
My Account
Vishay General Semiconductor - Diodes Division SMBJ78A-M3/5B
;;2.jpg)
- Part No.:
- SMBJ78A-M3/5B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78A-M3/5B.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:4,665
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMBJ78A-M3/5B 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 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 (IPPM), and 600 W peak pulse power rating with 10/1000 µs waveform - deployed in industrial motor drives, telecom power supplies, and automotive body control modules.
For engineers reviewing the SMBJ78A-M3/5B datasheet, SMBJ78A-M3/5B pinout, SMBJ78A-M3/5B application, or SMBJ78A-M3/5B equivalent, key selection criteria include clamping performance under 4.8 A surge, thermal resistance (RθJA = 100 °C/W), halogen-free RoHS compliance (M3 suffix), unidirectional polarity, and compatibility with automated SMT assembly on standard PCB pad layouts.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: when reverse voltage exceeds VBR, it avalanches to divert transient energy away from downstream ICs or MOSFETs. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1.0 µA at 78 V), while the SMB package supports high surge current handling without thermal runaway under repetitive 0.01% duty cycle pulses.
The device complies with IEC 61000-4-2 (ESD) and IEC 61000-4-4 (EFT) immunity requirements when properly laid out, and its 150 °C max junction temperature and MSL Level 1 rating enable reflow compatibility up to 260 °C peak. It is not AEC-Q101 qualified (lacks HE3/HM3 suffix), distinguishing it from automotive-grade variants.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 78 V - maximum continuous reverse operating voltage before significant leakage; defines safe DC rail margin for 72–80 V systems |
| 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 100 V-rated components |
| PPPM (Peak Pulse Power) | 600 W - energy-handling capacity for standardized 10/1000 µs waveform; supports IEC 61000-4-5 Level 3 surges |
| RθJA | 100 °C/W - thermal resistance junction-to-ambient on 0.2" × 0.2" copper pads; informs derating above 25 °C ambient |
| Polarity | Unidirectional - cathode marked by band; blocks forward conduction, clamps only reverse transients |
| Compliance | Halogen-free, RoHS-compliant (M3 suffix); meets JESD201 Class 2 whisker resistance |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, 2-terminal case with molded epoxy body and matte tin-plated leads. Dimensions: 4.57 mm × 3.94 mm × 2.20 mm (L × W × H), cathode band marking on one end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest-potential node; completes clamping path during reverse surge |
| Cathode | High-side transient input | Connected to protected line (e.g., 78 V rail); avalanche conduction occurs from cathode to anode |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power (10/1000 µs) | Enables protection against severe lightning-induced surges per IEC 61000-4-5 without external heat sinking |
| 126 V clamping at 4.8 A | Keeps protected 100 V MOSFETs or DC-DC controllers within safe operating area during 4.8 A transient events |
| Low incremental surge resistance | Minimizes voltage overshoot during fast-rising transients (<1 ns response), improving protection fidelity |
| MSL Level 1, 260 °C peak reflow | Supports single-pass lead-free reflow without moisture-related popcorning or delamination |
| Halogen-free, RoHS-compliant (M3) | Fulfills environmental compliance for industrial and consumer electronics sold in EU, China, and Korea |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Protection of 72–80 V DC bus against switching transients from IGBT gate drivers and relay coil flyback. IC Role / Device Role / Timing Role: Shunt clamping TVS placed across bulk capacitor input to limit voltage spikes to ≤126 V. Use Value: Prevents overvoltage failure of 100 V-rated electrolytic capacitors and gate drivers during 4.8 A inductive kick events. |
Use Scenario: Input-stage surge suppression on -48 V or +72 V telecom rectifier outputs exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary clamping element on DC output rail, coordinated with upstream MOVs and filters. Use Value: Limits transient voltage to 126 V during 600 W 10/1000 µs surges, preserving integrity of downstream DC-DC converters. |
| Automotive Body Control Modules | Programmable Logic Controllers |
Use Scenario: Protection of LIN bus power pins and microcontroller supply inputs against load dump and jump-start transients. IC Role / Device Role / Timing Role: Unidirectional TVS on 12 V or 24 V auxiliary rails, sized for 78 V standoff to accommodate battery variation. Use Value: Clamps 4.8 A surges to 126 V, preventing latch-up or burnout in 5 V/3.3 V LDO regulators fed from protected rails. |
Use Scenario: Field I/O protection in industrial PLC backplanes where 24 V or 48 V sensor/actuator lines face ESD and inductive coupling. IC Role / Device Role / Timing Role: Point-of-entry TVS on each channel's power line, mounted near connector to minimize loop inductance. Use Value: Ensures <1 µA leakage at 78 V standby, avoiding false triggering in high-impedance analog input circuits. |
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 electrical specs, RoHS-compliant but not halogen-free (E3 vs. M3) | Acceptable where halogen-free requirement is not mandated (e.g., non-EU commercial gear) | Select E3 for cost-sensitive, non-halogen-restricted designs; verify local regulatory compliance. |
| SMBJ78CA-M3/5B | Bidirectional variant; symmetric VBR (±86.7–95.8 V); no polarity marking | Required for AC-coupled or dual-polarity signal lines (e.g., RS-485, CAN bus) where reverse conduction must be blocked both ways | Choose CA version only if bidirectional clamping is needed; unidirectional SMBJ78A-M3/5B is optimal for DC rails. |
Compared with SMBJ78A-E3/5B, the M3 variant adds halogen-free compliance without performance trade-offs; versus SMBJ78CA-M3/5B, the unidirectional SMBJ78A-M3/5B provides lower leakage and avoids unnecessary bidirectional conduction in DC applications.
Availability
SMBJ78A-M3/5B is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, and programmable logic controllers requiring stable component supply, long-term obsolescence management, and consistent halogen-free material compliance.
Supply support for SMBJ78A-M3/5B 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, power handling, and industrial-grade qualification.
The SMBJ series was engineered for high-energy transient suppression in harsh environments - targeting DC power rail protection in industrial, telecom, and transportation systems where 600 W surge capability and stable clamping are critical.
FAQ
What is the maximum clamping voltage of SMBJ78A-M3/5B and under what test condition?
The SMBJ78A-M3/5B has a maximum clamping voltage (VC) of 126 V, measured at a peak pulse current (IPPM) of 4.8 A using the standardized 10/1000 µs double-exponential waveform. This value defines the upper voltage limit imposed on protected circuitry during worst-case surge events, and is confirmed per Vishay Document Number 88392, page 2.
Is SMBJ78A-M3/5B suitable for automotive applications requiring AEC-Q101 qualification?
No, SMBJ78A-M3/5B is not AEC-Q101 qualified. It carries the M3 suffix indicating halogen-free RoHS compliance for commercial-grade use. For automotive applications, Vishay specifies AEC-Q101 variants with HE3 or HM3 suffixes (e.g., SMBJ78AHE3_B), which undergo additional stress testing and lot traceability - SMBJ78A-M3/5B lacks those qualifications.
What does the "M3" suffix signify in SMBJ78A-M3/5B?
The "M3" suffix in SMBJ78A-M3/5B denotes halogen-free, RoHS-compliant construction meeting JEDEC J-STD-020 MSL Level 1 and JESD201 Class 2 whisker resistance requirements. It distinguishes the part from E3 (RoHS-compliant but not halogen-free) and HE3/HM3 (AEC-Q101 qualified) variants, confirming suitability for environmentally regulated industrial and consumer products.
How does SMBJ78A-M3/5B differ from SMBJ78CA-M3/5B?
SMBJ78A-M3/5B is unidirectional with cathode-band polarity marking and specified VBR only in reverse bias, whereas SMBJ78CA-M3/5B is bidirectional with symmetric breakdown (±86.7–95.8 V) and no polarity marking. The unidirectional SMBJ78A-M3/5B exhibits lower reverse leakage (<1.0 µA at 78 V) and is intended for DC rail protection; the CA version suits AC or dual-polarity signal lines like RS-485.
What PCB pad layout is recommended for optimal thermal performance of SMBJ78A-M3/5B?
Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad area per terminal for SMBJ78A-M3/5B to achieve the rated RθJA of 100 °C/W. Using smaller pads increases thermal resistance, reducing surge current capability and accelerating junction temperature rise - especially critical during repetitive 0.01% duty cycle pulses.
SMBJ78A-M3/5B Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AA, SMB
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMBJ)
SMBJ78A-M3/5B FAQ
1.How can I place an order for SMBJ78A-M3/5B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78A-M3/5B 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 SMBJ78A-M3/5B reliable?
The price and inventory of SMBJ78A-M3/5B are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ78A-M3/5B is usually 5 days.
3.What payment methods are accepted for SMBJ78A-M3/5B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78A-M3/5B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78A-M3/5B?
SMBJ78A-M3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78A-M3/5B 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 SMBJ78A-M3/5B?
For technical support, including SMBJ78A-M3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78A-M3/5B requirements.
6.How does Aetrix verify that SMBJ78A-M3/5B is sourced from the original manufacturer or authorized distributors?
All SMBJ78A-M3/5B 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 SMBJ78A-M3/5B meets industry standards.
7.What is the process for return or replacement of SMBJ78A-M3/5B?
All SMBJ78A-M3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78A-M3/5B, 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 SMBJ78A-M3/5B part is unused and in its original packaging.
Return procedure for SMBJ78A-M3/5B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78A-M3/5B Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Comparator circuit design covering voltage thresholds, input limits, open-collector outputs, LM393 wiring, op-amp differences, hysteresis, timing, window detection and practical fault diagnosis.
Schmitt triggers use separate rising and falling thresholds to stabilize slow or noisy signals. This guide covers hysteresis, 74HC14 and 74HCT14 selection, comparator calculations, RC oscillators and p…
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
