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Taiwan Semiconductor Corporation SMBJ51A
- Part No.:
- SMBJ51A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ51A.pdf
- Description:
- TVS DIODE 51VWM 82.4VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:11,628
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Product details
Overview
SMBJ51A from Taiwan Semiconductor is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, designed for high-energy surge protection in DC power rails and signal lines. It features a 51 V working stand-off voltage (VWM), 56.7–62.7 V breakdown voltage (VBR), and clamps transients to ≤82.4 V at 7.6 A peak impulse current (IPP), making it suitable for automotive load-dump and industrial I/O protection.
For engineers reviewing the SMBJ51A datasheet, SMBJ51A pinout, SMBJ51A application, or SMBJ51A equivalent, key selection criteria include clamping voltage margin relative to protected IC VDD, leakage current below 1 µA at 51 V, compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b, and thermal derating above 25°C ambient using RθJA = 55°C/W.
Technical Context
The SMBJ51A operates as a unidirectional avalanche diode, triggering when reverse voltage exceeds its specified VBR range (56.7–62.7 V at 1 mA test current). Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 µA at VWM = 51 V).
It delivers 600 W peak pulse power (10/1000 µs waveform), with fast response time <1.0 ps and junction temperature range of –55°C to +150°C. Thermal resistance values (RθJC = 10°C/W, RθJA = 55°C/W) support reliable operation under sustained surge conditions in compact PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 51 V - Maximum continuous reverse operating voltage before conduction begins; defines safe DC rail margin. |
| VBR min/max | 56.7 / 62.7 V @ 1 mA - Breakdown voltage range confirming consistent avalanche turn-on across production lots. |
| VC @ IPP | ≤82.4 V @ 7.6 A - Clamping voltage during 10/1000 µs surge; determines maximum stress on downstream circuitry. |
| PPK | 600 W - Peak pulse power handling capability per single 10/1000 µs transient event. |
| ID @ VWM | <1 µA - Reverse leakage at rated stand-off voltage; ensures minimal standby power loss and signal integrity. |
| TJ max | +150°C - Maximum junction temperature; enables use in under-hood automotive or high-ambient industrial environments. |
Pinout & Package
Package: DO-214AA (SMB), surface-mount, cathode-banded unidirectional configuration. Matte tin-plated leads, RoHS-compliant, halogen-free, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; defines polarity-sensitive placement on PCB. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 51 V rail); carries full surge current during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable, repeatable VBR over temperature and lifetime; eliminates parameter drift due to surface contamination. |
| Clamping voltage ≤82.4 V | Provides ≥20% margin below typical 100 V automotive load-dump peaks, protecting 60 V-rated MOSFETs and controllers. |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive switch-off), Pulse 2a/2b (battery disconnect), and Pulse 3a/3b (switching noise), meeting OEM requirements. |
| Fast response time <1.0 ps | Activates before ESD or lightning-induced transients can damage sensitive inputs; no delay-induced overshoot. |
Applications
| Automotive Power Rail Protection | Industrial I/O Interface Protection |
|---|---|
Use Scenario: Protecting 5V–48V microcontroller power supplies and CAN/LIN bus lines against load dump and jump-start surges in vehicle ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp transients before they reach LDOs or MCU VDD pins. Use Value: Limits voltage excursion to ≤82.4 V during 600 W pulses, preventing latch-up or gate oxide rupture in 51 V system rails. |
Use Scenario: Safeguarding PLC analog input channels (4–20 mA, 0–10 V) and digital GPIOs from field-wiring induced surges and EFT bursts. IC Role / Device Role / Timing Role: Standoff protection device mounted at connector entry point, shunting energy away from precision ADC front-ends and isolation barriers. Use Value: Sub-1 µA leakage preserves measurement accuracy; 82.4 V clamping prevents saturation of op-amps and overvoltage damage to isolators. |
| LED Driver Supply Protection | Telecom DC Power Input Protection |
Use Scenario: Securing constant-current LED driver ICs and MOSFET switches in streetlight and signage systems exposed to lightning-induced surges on 24–48 V DC feeds. IC Role / Device Role / Timing Role: Primary surge suppression element placed upstream of buck controller ICs and high-side switches. Use Value: Withstands repetitive 600 W pulses without degradation; 150°C TJ rating supports operation inside thermally constrained outdoor enclosures. |
Use Scenario: Protecting PoE-powered equipment (e.g., IP cameras, wireless APs) from AC/DC adapter transients and Ethernet-coupled surges on 48 V DC input rails. IC Role / Device Role / Timing Role: First-line defense on DC input path before DC-DC converters and PMICs, absorbing energy from external power supply faults. Use Value: 51 V VWM aligns with 48 V nominal PoE+ systems; 82.4 V VC ensures downstream 60 V-rated FETs remain within SOA 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 |
|---|---|---|---|
| SMBJ51CA | Bidirectional variant; symmetric VBR (56.7–62.7 V) in both polarities; same VWM, VC, and PPK ratings. | Required for AC-coupled or dual-polarity signal lines (e.g., RS-485, USB D+/D−); not suitable for DC rail protection where polarity matters. | Select SMBJ51CA only when protecting bidirectional data lines; SMBJ51A remains optimal for unidirectional power rails. |
| SAC51A | Same VWM (51 V) and VC (82.4 V), but lower PPK (400 W); smaller SOD-123FL package; higher RθJA (~125°C/W). | Limited to lower-energy transients (e.g., ESD-only); unsuitable for ISO 7637-2 Pulse 1/2a/2b; requires tighter thermal layout. | Choose SAC51A only for space-constrained, low-surge applications; SMBJ51A is required for full automotive-grade surge immunity. |
Compared with SMBJ51CA and SAC51A, the SMBJ51A uniquely balances 600 W surge capacity, unidirectional polarity control, and DO-214AA thermal performance-making it the preferred choice for robust DC power rail protection where clamping margin, reliability, and standard SMB footprint matter.
Availability
SMBJ51A is available at Aetrix Electronics and suitable for automotive electronics, industrial PLCs, LED lighting systems, and telecom power supplies requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for SMBJ51A 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs, with global distribution and AEC-Q200 qualified product lines.
The SMBJ series was developed specifically for high-reliability transient suppression in automotive and industrial environments, emphasizing ISO 7637-2 compliance, tight VBR tolerance, and robust thermal performance in surface-mount packages.
FAQ
What is the maximum clamping voltage of SMBJ51A under surge conditions?
The SMBJ51A has a maximum clamping voltage (VC) of 82.4 V when subjected to its rated peak impulse current (IPP) of 7.6 A using the standard 10/1000 µs waveform. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during transient events. Designers must verify that this clamping level remains safely below the absolute maximum ratings of downstream components.
Is SMBJ51A suitable for bidirectional signal line protection?
No, SMBJ51A is a unidirectional TVS diode intended for DC power rail or single-polarity signal protection. For bidirectional applications such as RS-485, CAN, or AC-coupled interfaces, the SMBJ51CA variant-featuring symmetrical breakdown in both directions-must be used instead. Using SMBJ51A on bidirectional lines risks forward conduction and failure during negative transients.
Does SMBJ51A meet automotive surge immunity standards?
Yes, SMBJ51A meets ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (battery disconnection), and Pulse 3a/3b (switching noise), as confirmed in Taiwan Semiconductor's official documentation. Its 600 W peak power rating and controlled clamping behavior make it suitable for AEC-Q200-compliant designs when paired with appropriate board-level layout practices.
What is the leakage current specification for SMBJ51A at its working voltage?
SMBJ51A exhibits a maximum blocking leakage current (ID) of less than 1 µA when biased at its working stand-off voltage (VWM) of 51 V. This ultra-low leakage ensures minimal power loss in always-on systems and preserves signal integrity in high-impedance sensing circuits, such as those found in battery monitoring or precision analog front-ends.
Can SMBJ51A be used in place of SMBJ51 without redesigning the PCB?
Yes, SMBJ51A and SMBJ51 share identical DO-214AA (SMB) package dimensions, pinout, and mounting footprint. However, SMBJ51A offers tighter VBR tolerance (56.7–62.7 V vs. 56.7–69.3 V for SMBJ51) and lower clamping voltage (82.4 V vs. 91.1 V), providing improved protection margin. No PCB changes are needed for drop-in replacement, though system-level validation is recommended.
SMBJ51A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 7.3A
- 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 (SMB)
SMBJ51A FAQ
1.How can I place an order for SMBJ51A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ51A 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 SMBJ51A reliable?
The price and inventory of SMBJ51A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ51A is usually 5 days.
3.What payment methods are accepted for SMBJ51A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ51A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ51A?
SMBJ51A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ51A 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 SMBJ51A?
For technical support, including SMBJ51A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ51A requirements.
6.How does Aetrix verify that SMBJ51A is sourced from the original manufacturer or authorized distributors?
All SMBJ51A 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 SMBJ51A meets industry standards.
7.What is the process for return or replacement of SMBJ51A?
All SMBJ51A units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ51A, 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 SMBJ51A part is unused and in its original packaging.
Return procedure for SMBJ51A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ51A Tags
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