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Vishay General Semiconductor - Diodes Division SMBJ51D-M3/I
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- Part No.:
- SMBJ51D-M3/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ51D-M3/I.pdf
- Description:
- TVS DIODE 51VWM 81.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,237
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Product details
Overview
SMBJ51D-M3/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 51 V stand-off voltage (VWM), 57.6–61.8 V breakdown voltage (VBR) at 1 mA, 81.2 V maximum clamping voltage (VC) at 7.4 A peak pulse current, and 600 W peak pulse power rating with 10/1000 μs waveform - deployed in industrial power supplies and sensor interface circuits.
For engineers reviewing the SMBJ51D-M3/I datasheet, SMBJ51D-M3/I pinout, SMBJ51D-M3/I application, or SMBJ51D-M3/I equivalent, this page delivers verified electrical parameters, package dimensions, clamping behavior under surge conditions, thermal derating curves, and validated alternative parts for ESD and lightning-induced transient suppression in 24–48 V systems.
Technical Context
This TVS diode operates as a unidirectional clamping device: reverse-biased during normal operation with ≤0.5 μA leakage at 51 V, then rapidly avalanching to limit transient voltages when exceeding VBR. Its low incremental surge resistance and fast response time (<1 ns) ensure minimal let-through energy to downstream ICs like microcontrollers and RS-485 transceivers.
The SMBJ51D-M3/I is rated for 150 °C maximum junction temperature, meets MSL Level 1 per J-STD-020, and uses matte tin-plated leads compliant with J-STD-002 solderability standards. Its halogen-free, RoHS-compliant construction (M3 suffix) supports industrial-grade reliability under repetitive surge stress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 51 V - maximum continuous reverse operating voltage before significant leakage begins; sets protection threshold for 48 V nominal DC systems. |
| VBR (Breakdown Voltage) | 57.6–61.8 V at 1 mA - tight ±3.5 % tolerance ensures consistent triggering across production lots. |
| VC (Clamping Voltage) | 81.2 V at 7.4 A IPPM - defines worst-case voltage seen by protected circuit during 600 W transient event. |
| PPPM (Peak Pulse Power) | 600 W (10/1000 μs waveform) - quantifies single-event surge energy handling capability without failure. |
| ID (Reverse Leakage) | ≤0.5 μA at 51 V - negligible standby current avoids loading sensitive reference or bias networks. |
| RθJA | 125 °C/W (on minimum pad layout) - determines thermal rise under sustained power dissipation; requires PCB copper area management. |
| Polarity | Unidirectional - cathode marked by band; blocks forward conduction, clamps only reverse transients. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, M3 industrial grade. Dimensions: 4.57 mm × 3.94 mm × 2.20 mm (L × W × H); cathode indicated by molded band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Low-side reference node | Connected to ground or lowest potential rail; completes clamping path during transient events. |
| Cathode (banded end) | Protected line input | Connected to line being protected (e.g., 48 V supply rail); avalanche conduction occurs from cathode to anode. |
Key Features
| Feature | Design Value |
|---|---|
| ±3.5 % VBR tolerance | Enables precise coordination with system overvoltage thresholds without margin stacking in multi-stage protection schemes. |
| 600 W peak pulse power (10/1000 μs) | Withstands IEC 61000-4-5 Level 4 surges (4 kV line-earth) on 48 V DC distribution buses. |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow without baking; compatible with high-volume SMT assembly. |
| Low 0.5 μA leakage at VWM | Preserves battery life in always-on industrial sensors and avoids false triggers in high-impedance monitoring circuits. |
| Halogen-free & RoHS-compliant (M3) | Meets IPC-1752A material declaration requirements for automotive and industrial OEM programs. |
Applications
| Industrial PLC I/O Protection | 48 V Telecom Power Rail Clamp |
|---|---|
|
Use Scenario: Protecting digital input modules from inductive kickback and field-wiring transients in factory automation cabinets. IC Role / Device Role / Timing Role: Unidirectional TVS placed between field-side terminal and optocoupler input, clamping spikes before they reach isolation barrier. Use Value: Prevents latch-up or permanent damage to 24–48 V-rated logic inputs while maintaining <0.5 μA standby leakage. |
Use Scenario: Safeguarding DC-DC converter inputs in telecom base station power shelves exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary clamping device on 48 V backplane feed, coordinated with upstream MOVs and downstream polymer PTCs. Use Value: Limits let-through voltage to ≤81.2 V during 600 W transients, keeping downstream converters within absolute maximum ratings. |
| Automotive Body Control Module (BCM) | RS-485 Sensor Bus Protection |
|
Use Scenario: Suppressing load-dump and jump-start transients on 12–48 V auxiliary power nets in vehicle body electronics. IC Role / Device Role / Timing Role: Unidirectional TVS mounted directly at connector entry point, shunting energy to chassis ground. Use Value: Survives ISO 7637-2 Pulse 5a (75 V/350 ms) with no degradation due to 150 °C TJ max and robust silicon construction. |
Use Scenario: Shielding differential RS-485 transceivers in industrial sensor networks from ESD and cable discharge events. IC Role / Device Role / Timing Role: Paired unidirectional TVS devices (one per line) referenced to common-mode ground, clamping common-mode surges. Use Value: Maintains signal integrity with <1 ns response and 81.2 V clamping, preventing transceiver latch-up during 8 kV contact ESD (IEC 61000-4-2). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ51A-M3/I | Bidirectional variant; symmetric clamping in both polarities; same VBR/VWM range but no polarity marking. | Required where AC-coupled or floating lines (e.g., Ethernet PHY pairs) need protection against bipolar transients. | Select SMBJ51A-M3/I only if bidirectional clamping is explicitly required; SMBJ51D-M3/I is optimal for DC rails with defined ground reference. |
| SMCJ51A-M3/I | Larger SMC (DO-214AB) package; 1500 W PPPM rating; higher thermal mass; identical electrical specs except RθJA = 40 °C/W. | Suitable for higher-energy surge environments (e.g., outdoor power converters) where PCB space allows larger footprint. | Choose SMCJ51A-M3/I when 600 W is insufficient and board layout permits 7.11 mm × 6.22 mm footprint; otherwise SMBJ51D-M3/I offers best density/performance balance. |
Compared with SMBJ51A-M3/I, the SMBJ51D-M3/I provides superior unidirectional precision for grounded DC systems, while SMCJ51A-M3/I trades smaller size for higher surge capacity - making SMBJ51D-M3/I the preferred choice for space-constrained 48 V industrial controls where polarity is fixed.
Availability
SMBJ51D-M3/I is available at Aetrix Electronics and suitable for industrial automation, telecom power systems, and automotive body electronics requiring stable component supply, long-term lifecycle support, and traceable halogen-free sourcing.
Supply support for SMBJ51D-M3/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 application-specific performance.
The SMBJ series is engineered for high-reliability transient suppression in harsh environments - targeting industrial, telecom, and automotive applications where consistent clamping, low leakage, and MSL-1 manufacturability are critical.
FAQ
What is the maximum clamping voltage of SMBJ51D-M3/I at its rated peak pulse current?
The SMBJ51D-M3/I has a maximum clamping voltage (VC) of 81.2 V at 7.4 A peak pulse current (IPPM), measured using the standardized 10/1000 μs double-exponential surge waveform. This value defines the upper voltage limit imposed on protected circuitry during a full 600 W transient event, ensuring downstream components remain within safe operating limits.
Is SMBJ51D-M3/I suitable for protecting 48 V DC power supplies?
Yes, SMBJ51D-M3/I is specifically suited for 48 V DC systems: its 51 V stand-off voltage (VWM) provides adequate margin above nominal rail voltage, while its 57.6–61.8 V breakdown range ensures reliable triggering before damaging overvoltage occurs. The 81.2 V clamping voltage also stays well below typical 100 V absolute maximum ratings of industrial DC-DC converters.
Does SMBJ51D-M3/I have a bidirectional variant?
Yes - the bidirectional counterpart is SMBJ51A-M3/I (not SMBJ51CD). It shares identical voltage ratings and surge capability but clamps symmetrically in both directions, with no cathode band marking. SMBJ51D-M3/I remains unidirectional and must be oriented with the banded end toward the protected line.
What is the thermal resistance of SMBJ51D-M3/I on standard PCB pads?
The SMBJ51D-M3/I exhibits a typical junction-to-ambient thermal resistance (RθJA) of 125 °C/W when mounted on the minimum recommended pad layout per Vishay's datasheet. This value rises significantly without adequate copper area, so thermal design must allocate ≥5.0 mm × 5.0 mm copper for sustained power dissipation near its 1.0 W TA = 25 °C limit.
How does the M3 suffix affect SMBJ51D-M3/I's compliance and reliability?
The M3 suffix indicates SMBJ51D-M3/I is halogen-free, RoHS-compliant, and qualified to JESD 201 Class 2 for tin whisker resistance - confirming suitability for industrial and automotive applications with strict material and long-term reliability requirements. It also meets MSL Level 1, enabling direct placement without pre-baking.
SMBJ51D-M3/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):
- 51V
- Voltage - Breakdown (Min):
- 57.6V
- Voltage - Clamping (Max) @ Ipp:
- 81.2V
- Current - Peak Pulse (10/1000µs):
- 7.4A
- 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)
SMBJ51D-M3/I FAQ
1.How can I place an order for SMBJ51D-M3/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ51D-M3/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 SMBJ51D-M3/I reliable?
The price and inventory of SMBJ51D-M3/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ51D-M3/I is usually 5 days.
3.What payment methods are accepted for SMBJ51D-M3/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ51D-M3/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ51D-M3/I?
SMBJ51D-M3/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ51D-M3/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 SMBJ51D-M3/I?
For technical support, including SMBJ51D-M3/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ51D-M3/I requirements.
6.How does Aetrix verify that SMBJ51D-M3/I is sourced from the original manufacturer or authorized distributors?
All SMBJ51D-M3/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 SMBJ51D-M3/I meets industry standards.
7.What is the process for return or replacement of SMBJ51D-M3/I?
All SMBJ51D-M3/I units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ51D-M3/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 SMBJ51D-M3/I part is unused and in its original packaging.
Return procedure for SMBJ51D-M3/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ51D-M3/I Tags
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