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Vishay General Semiconductor - Diodes Division SMBJ78CA-M3/5B
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- Part No.:
- SMBJ78CA-M3/5B
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ78CA-M3/5B.pdf
- Description:
- TVS DIODE 78VWM 126VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:2,686
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Product details
Overview
SMBJ78CA-M3/5B 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 signal or power 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 capability with 10/1000 µs waveform - used to protect MOSFETs, sensor interfaces, and industrial I/O circuits against ESD and inductive switching surges.
For engineers reviewing the SMBJ78CA-M3/5B datasheet, SMBJ78CA-M3/5B pinout, SMBJ78CA-M3/5B application, or SMBJ78CA-M3/5B equivalent, key selection criteria include bidirectional clamping symmetry, low clamping ratio (VC/VBR ≈ 1.34), MSL Level 1 moisture sensitivity, halogen-free RoHS compliance (M3 suffix), and compatibility with automated SMT placement on PCBs with 5.0 mm × 5.0 mm copper pads per terminal.
Technical Context
This bidirectional TVS operates identically in both polarities, with symmetrical breakdown and clamping characteristics. Its glass-passivated junction enables fast response time (<1 ns) and stable performance over temperature (VBR tempco = 0.106 %/°C), while the low incremental surge resistance ensures minimal voltage overshoot during transient events.
The device is rated for repetitive 10/1000 µs pulses at 0.01 % duty cycle and derates linearly above TA = 25 °C (RθJA = 100 °C/W). It meets UL 497B recognition (QVGQ2) and is qualified to JESD201 Class 2 whisker resistance, with matte tin-plated leads solderable per J-STD-002 and JESD22-B102.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 78 V - maximum continuous reverse operating voltage before clamping begins; defines safe operating margin for 72–84 V nominal bus systems. |
| VBR (min/max) | 86.7 V / 95.8 V at IT = 1 mA - guaranteed symmetric breakdown threshold in both directions; ensures predictable turn-on across manufacturing lot and temperature. |
| VC @ IPPM | 126 V at 4.8 A - clamped voltage during 10/1000 µs transient; limits downstream IC stress to ≤126 V under worst-case 600 W surge. |
| PPPM | 600 W - peak pulse power handling with 10/1000 µs waveform; supports protection of 24 V, 48 V, and 72 V industrial control lines. |
| ID @ VWM | 1.0 µA - ultra-low leakage at stand-off voltage; avoids signal distortion or bias shift in high-impedance sensor or analog front-end circuits. |
| TJ max. | +150 °C - maximum junction temperature; enables operation in enclosed enclosures or near heat-generating components without derating. |
| Package | SMB (DO-214AA) - standardized 2-pin surface-mount outline with 5.59 mm × 4.06 mm footprint; compatible with IPC-7351B SMB footprint and standard reflow profiles. |
Pinout & Package
Package: SMB (DO-214AA), bidirectional - no polarity marking; terminals are symmetrical anode/cathode pair. Mounting requires 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per lead for rated thermal and surge performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient return path (bidirectional) | Acts as cathode during positive transients and anode during negative transients; connects to protected line (e.g., RS-485 A/B, CAN H/L, or DC bus). |
| Cathode | Transient return path (bidirectional) | Electrically identical to Anode; forms symmetrical clamp pair - either terminal may connect to line or ground depending on layout constraints. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Identical VBR and VC in both polarities - eliminates need for polarity-aware placement and supports AC-coupled or floating signal lines (e.g., Ethernet PHY, isolated RS-485). |
| 600 W peak pulse power | Handles IEC 61000-4-5 Level 4 surges (4 kV, 2 Ω source) on 48 V lines without failure when mounted per recommended pad layout. |
| MSL Level 1 rating | Unlimited floor life at ≤30 °C/60 % RH - allows direct use from reel without baking, reducing SMT line downtime and moisture-related defects. |
| Halogen-free & RoHS-compliant (M3) | Fulfills EU RoHS Directive 2011/65/EU and JEDEC JS709E halogen restrictions - required for export to EU, South Korea, and China RoHS markets. |
| UL 497B recognized (QVGQ2) | Validated for telecom and industrial protector applications per Underwriters Laboratories - simplifies end-equipment safety certification. |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Protecting 24 V digital input channels in programmable logic controllers from inductive kickback (e.g., solenoid de-energization) and field-wiring ESD. IC Role / Device Role: Bidirectional transient clamp placed between input terminal and controller GPIO, referenced to local ground. Use Value: Limits transient voltage to ≤126 V, preventing latch-up or damage to 3.3 V/5 V microcontroller inputs via optocoupler or level-shifter isolation stages. |
Use Scenario: Safeguarding LIN bus transceivers and window motor driver ICs against load dump and jump-start surges in vehicle body electronics. IC Role / Device Role: Line-side TVS on LIN data line and 12 V supply rail, installed upstream of LDO regulators and communication ICs. Use Value: Withstands 10/1000 µs surges up to 600 W while maintaining <1 µA leakage - avoids false wake-up or communication errors during low-power sleep modes. |
| Telecom Power Feeding Interface | Smart Sensor Signal Conditioning |
|
Use Scenario: Protecting PoE-powered devices (e.g., IP cameras) on 48 V DC feed lines against lightning-induced common-mode surges entering via Ethernet cable shield. IC Role / Device Role: Common-mode clamp between +48 V and return, paired with differential-mode TVS on data pairs. Use Value: Symmetric 78 V VWM aligns with IEEE 802.3af/at hold-up requirements; 126 V VC ensures downstream DC-DC converter input remains within absolute max rating. |
Use Scenario: Shielding analog output pins (e.g., 4–20 mA transmitter) and digital sensor outputs (I²C, SPI) from ESD events during factory handling or field maintenance. IC Role / Device Role: Low-leakage TVS placed directly at connector interface, before precision op-amps or ADC drivers. Use Value: 1.0 µA ID at 78 V prevents loading of high-impedance sensor bridges or current-loop sense resistors; SMB footprint minimizes board space without sacrificing surge margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ78CA-E3/5B | Same electrical specs and SMB package; RoHS-compliant but contains brominated flame retardants (not halogen-free). | Acceptable for commercial-grade non-automotive designs where halogen content is unrestricted. | Select SMBJ78CA-E3/5B only if halogen-free compliance is not mandated by regional regulations or OEM specifications. |
| SMCJ78CA-M3 | Higher 1500 W PPPM rating in larger SMC (DO-214AB) package; same VWM/VBR/VC specs; RθJA = 40 °C/W vs. 100 °C/W. | Better suited for high-energy surge environments (e.g., outdoor telecom cabinets) where PCB area permits larger footprint. | Choose SMCJ78CA-M3 when system-level surge testing exceeds IEC 61000-4-5 Level 4 or when thermal management requires lower junction-to-ambient resistance. |
Compared with SMBJ78CA-M3/5B, SMBJ78CA-E3/5B offers identical protection performance but lacks halogen-free status, while SMCJ78CA-M3 delivers 2.5× higher surge energy handling at the cost of 2.5× larger board area and different thermal design requirements.
Availability
SMBJ78CA-M3/5B is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control modules, and telecom power feeding interfaces requiring stable component supply, halogen-free compliance, and UL-recognized surge immunity.
Supply support for SMBJ78CA-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 efficiency, and AEC-Q qualification.
The SMBJ series was engineered for robust, automated-solderable transient protection in harsh industrial and automotive environments - balancing high surge capability, low leakage, and compact SMB packaging for space-constrained PCBs.
FAQ
What is the clamping voltage of SMBJ78CA-M3/5B at its rated peak pulse current?
The SMBJ78CA-M3/5B has a maximum clamping voltage (VC) of 126 V at 4.8 A peak pulse current (IPPM) with a 10/1000 µs waveform. This value is measured under standardized test conditions per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during a full-rated transient event. The SMBJ78CA-M3/5B maintains this clamping performance bidirectionally, ensuring consistent protection regardless of surge polarity.
Is SMBJ78CA-M3/5B suitable for automotive applications?
SMBJ78CA-M3/5B is not AEC-Q101 qualified - it carries the commercial-grade M3 suffix, not HM3_X. For automotive use, Vishay specifies the HM3_X variant (e.g., SMBJ78CAHM3_B/I), which undergoes additional stress testing per AEC-Q101. The SMBJ78CA-M3/5B remains appropriate for industrial and telecom applications where AEC-Q101 is not mandated, but should not be deployed in safety-critical or OEM automotive ECUs without formal qualification validation.
How does the M3 suffix affect the environmental compliance of SMBJ78CA-M3/5B?
The M3 suffix on SMBJ78CA-M3/5B indicates halogen-free, RoHS-compliant construction per JEDEC JS709E and EU Directive 2011/65/EU, with brominated and chlorinated flame retardants excluded from the molding compound. This distinguishes it from the E3 suffix (RoHS-compliant but not halogen-free) and supports compliance with strict environmental requirements in EU, South Korea, and China markets. The SMBJ78CA-M3/5B meets all applicable material declarations without compromising electrical or thermal performance.
What is the thermal resistance of SMBJ78CA-M3/5B, and how does it impact layout design?
SMBJ78CA-M3/5B 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 minimum recommended pad layout per Vishay's datasheet Figure 5. To maintain TJ ≤ 150 °C under sustained 5.0 W power dissipation, designers must ensure adequate copper area and avoid excessive ambient temperature rise. The SMBJ78CA-M3/5B does not require heatsinking for transient-only operation but benefits from thermal relief in high-duty-cycle scenarios.
Can SMBJ78CA-M3/5B be used in place of a unidirectional TVS like SMBJ78A-M3/5B?
No - SMBJ78CA-M3/5B is strictly bidirectional and lacks polarity marking, whereas SMBJ78A-M3/5B is unidirectional with a cathode band. Substituting them requires circuit review: bidirectional use enables AC or floating-line protection but doubles leakage path; unidirectional use provides lower forward voltage drop (VF ≤ 3.5 V at 50 A) for DC rail clamping. The SMBJ78CA-M3/5B cannot replace SMBJ78A-M3/5B in circuits relying on DC blocking or asymmetric surge paths without redesigning grounding and placement.
SMBJ78CA-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:
- -
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMBJ)
SMBJ78CA-M3/5B FAQ
1.How can I place an order for SMBJ78CA-M3/5B through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ78CA-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 SMBJ78CA-M3/5B reliable?
The price and inventory of SMBJ78CA-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 SMBJ78CA-M3/5B is usually 5 days.
3.What payment methods are accepted for SMBJ78CA-M3/5B?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ78CA-M3/5B transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ78CA-M3/5B?
SMBJ78CA-M3/5B orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ78CA-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 SMBJ78CA-M3/5B?
For technical support, including SMBJ78CA-M3/5B datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ78CA-M3/5B requirements.
6.How does Aetrix verify that SMBJ78CA-M3/5B is sourced from the original manufacturer or authorized distributors?
All SMBJ78CA-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 SMBJ78CA-M3/5B meets industry standards.
7.What is the process for return or replacement of SMBJ78CA-M3/5B?
All SMBJ78CA-M3/5B units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ78CA-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 SMBJ78CA-M3/5B part is unused and in its original packaging.
Return procedure for SMBJ78CA-M3/5B:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ78CA-M3/5B Tags
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