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STMicroelectronics SMBJ33A-TR
- Part No.:
- SMBJ33A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ33A-TR.pdf
- Description:
- TVS DIODE 33VWM 53.3VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:24,409
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Product details
Overview
SMBJ33A-TR from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for primary-level surge protection on DC power rails and signal lines. It features a 33 V standoff voltage (VRM), 53.3 V clamping voltage at 11.8 A (10/1000 µs), 600 W peak pulse power rating, and operates up to 150 °C junction temperature-deployed in industrial power supplies and automotive body control modules to safeguard MOSFETs and microcontrollers against IEC 61000-4-4 and -4-2 transients.
For engineers reviewing the SMBJ33A-TR datasheet, SMBJ33A-TR pinout, SMBJ33A-TR application, or SMBJ33A-TR equivalent, key selection criteria include clamping performance under 10/1000 µs surges, low leakage (<0.2 µA @ 25 °C), UL497B recognition for isolated loop circuits, and SMB package thermal robustness in high-reliability 24 V DC systems.
Technical Context
This TVS diode uses planar silicon junction technology to achieve stable breakdown behavior and low dynamic resistance (1.08 Ω), enabling precise voltage clamping during fast-rising transients such as inductive switch-off spikes or ESD events. Its unidirectional configuration supports DC-biased protection paths without reverse conduction.
The device complies with IEC 61000-4-2 (30 kV air/contact discharge) and IEC 61000-4-4 Level 4 (4 kV), and is UL497B-recognized (E136224) for use in isolated loop circuit protection-making it suitable for safety-critical industrial interfaces where failure mode must remain short-circuit under overstress.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 33 V - Maximum continuous reverse operating voltage before clamping initiates; sets protection threshold for 24 V nominal DC rails. |
| Breakdown Voltage (VBR min) | 36.7 V @ 1 mA - Guaranteed minimum avalanche onset; ensures reliable triggering above system operating voltage. |
| Clamping Voltage (VCL) | 53.3 V @ 11.8 A (10/1000 µs) - Peak voltage seen by protected IC during surge; limits stress on downstream 3.3 V/5 V logic. |
| Peak Pulse Power (PPP) | 600 W (10/1000 µs) - Sustained energy absorption capability at 25 °C; derates to 350 W at 150 °C junction temp. |
| Leakage Current (IRM) | 0.2 µA @ 25 °C - Minimal standby current draw; preserves battery life and avoids false triggering in low-power sensor nodes. |
| Junction Temperature Range | –55 °C to +150 °C - Enables deployment in under-hood automotive or industrial environments without thermal derating penalties. |
| Package | SMB (DO-214AA) - Standardized surface-mount outline (5.6 × 3.95 mm) with IPC-7531-compliant footprint and matte tin leads. |
Pinout & Package
SMBJ33A-TR is housed in an SMB (DO-214AA) package: a 2-terminal, unidirectional surface-mount device with cathode band marking. The package measures 5.6 mm × 3.95 mm × 2.45 mm (L × W × H), features J-STD-002-compliant solderable matte tin-plated leads, and is rated MSL Level 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Low-side reference node | Connected to ground or low-voltage rail; completes clamping path when transient exceeds VRM. |
| Cathode (banded end) | Protected line input | Connected to the line being protected (e.g., 24 V supply); conducts surge current to ground during overvoltage. |
Key Features
| Feature | Design Value |
|---|---|
| UL497B Recognition | Agency file E136224 confirms suitability for isolated loop circuit protection in industrial control systems. |
| High-Temperature Stability | Rated for full 600 W surge handling up to 150 °C junction temperature-critical for enclosed power converters. |
| Low Dynamic Resistance | 1.08 Ω enables tight clamping window (53.3 V @ 11.8 A), minimizing voltage overshoot on sensitive loads. |
| ESD Robustness | Exceeds IEC 61000-4-2 Level 4: 30 kV air/contact discharge-protects USB, CAN, and RS-485 interfaces. |
| Planar Junction Construction | Delivers consistent VBR tolerance and low leakage across temperature-essential for long-life embedded deployments. |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module |
|---|---|
|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) power supply exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary surge clamp on main DC rail, placed upstream of DC-DC converter input. Use Value: Limits transient voltage to ≤53.3 V, preventing damage to 60 V-rated input MOSFETs and ensuring uninterrupted operation during 100 ms load dump events. |
Use Scenario: LIN bus line protection in door module ECU subjected to battery reversal and ESD during assembly. IC Role / Device Role / Timing Role: Unidirectional TVS on LIN signal line (biased at 12 V), referenced to chassis ground. Use Value: Clamps fast ESD transients (<1 ns rise time) below 53.3 V while adding <10 pF capacitance-preserving LIN signal integrity at 19.2 kbps. |
| Telecom DC Feeder Protection | Smart Meter Power Input |
|
Use Scenario: –48 V DC telecom power feed line vulnerable to lightning-induced surges on outdoor cabinets. IC Role / Device Role / Timing Role: First-stage protector on –48 V rail, coordinated with MOV-based secondary protection. Use Value: Absorbs 600 W (10/1000 µs) surges without thermal runaway, maintaining clamping voltage within safe margin for –53 V-rated rectifier diodes. |
Use Scenario: 220 V AC-to-DC auxiliary supply input in smart electricity meter installed in utility substations. IC Role / Device Role / Timing Role: Secondary surge suppressor on 12 V DC output rail feeding metrology IC and RTC. Use Value: Provides low-leakage (<0.2 µA) protection that avoids drift in precision voltage references while surviving repeated 4 kV IEC 61000-4-4 surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33CA-TR | Bidirectional version; symmetric clamping (±53.3 V); higher capacitance (~25 pF @ 0 V). | Required for AC-coupled or dual-polarity signal lines (e.g., RS-485, CAN FD differential pairs). | Select only if protecting bidirectional signals; not interchangeable on DC rails due to reverse conduction risk. |
| SMAJ33A-TR | Lower power rating (400 W vs. 600 W); larger VCL (59 V @ 6.8 A); same SMB footprint but lower thermal mass. | Suitable for cost-sensitive consumer electronics with lower surge exposure (IEC 61000-4-4 Level 2). | Use where 600 W headroom is unnecessary; avoid in industrial/automotive where 4 kW (8/20 µs) capability matters. |
Compared with SMBJ33CA-TR and SMAJ33A-TR, SMBJ33A-TR uniquely balances high 600 W surge capacity, low 1.08 Ω dynamic resistance, and UL497B certification-making it the preferred choice for safety-critical 24 V DC protection where clamping precision and regulatory compliance are non-negotiable.
Availability
SMBJ33A-TR is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, telecom DC feeders, and smart meter power inputs requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for SMBJ33A-TR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, specializing in power management, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.
SMBJ33A-TR belongs to ST's high-reliability TVS diode portfolio, engineered specifically for robust transient suppression in harsh environments-emphasizing low leakage, high-temperature stability, and international safety certifications.
FAQ
What is the maximum clamping voltage of SMBJ33A-TR under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 53.3 V at 11.8 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature at a rate of 1000 ppm/°C (αT = 10⁻⁴/°C), reaching ~55.5 V at 150 °C junction temperature per the datasheet's thermal coefficient formula.
Is SMBJ33A-TR suitable for protecting CAN bus lines?
No-SMBJ33A-TR is unidirectional and optimized for DC rail protection, not differential data lines. For CAN FD or high-speed CAN, a bidirectional TVS like SMBJ33CA-TR or a dedicated low-capacitance CAN protector (e.g., ESDCAN03-2BM) is required to avoid signal distortion and ensure common-mode transient immunity.
Does SMBJ33A-TR meet automotive qualification standards?
SMBJ33A-TR is not AEC-Q200 qualified, though its –55 °C to +150 °C operating range and robust surge ratings make it widely used in non-safety-critical automotive subsystems (e.g., body electronics). For ASIL-B/C applications, ST recommends AEC-Q200-qualified alternatives like the SMA6J33A-Q or automotive-grade Transil™ series.
How does the SMB package compare thermally to SMA or SMC packages for this device?
The SMB package offers lower thermal resistance than SMA (DO-214AC) but higher than SMC (DO-214AB). With Rth(j-a) ≈ 120 °C/W on a standard FR4 PCB (70 µm Cu), SMBJ33A-TR dissipates heat effectively for intermittent surges; however, for sustained high-power operation, SMC-packaged equivalents (e.g., SMCJ33A) provide ~30% better thermal performance due to larger copper area and lead frame mass.
SMBJ33A-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 11.8A
- 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:
- SMB
SMBJ33A-TR FAQ
1.How can I place an order for SMBJ33A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ33A-TR 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 SMBJ33A-TR reliable?
The price and inventory of SMBJ33A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ33A-TR is usually 5 days.
3.What payment methods are accepted for SMBJ33A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ33A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ33A-TR?
SMBJ33A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ33A-TR 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 SMBJ33A-TR?
For technical support, including SMBJ33A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ33A-TR requirements.
6.How does Aetrix verify that SMBJ33A-TR is sourced from the original manufacturer or authorized distributors?
All SMBJ33A-TR 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 SMBJ33A-TR meets industry standards.
7.What is the process for return or replacement of SMBJ33A-TR?
All SMBJ33A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ33A-TR, 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 SMBJ33A-TR part is unused and in its original packaging.
Return procedure for SMBJ33A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ33A-TR Tags
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