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onsemi 1SMB33AT3
- Part No.:
- 1SMB33AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMB33AT3.pdf
- Description:
- TVS DIODE 33V 53.3V SMB
- Quantity:
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Inventory:2,178
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Product details
Overview
1SMB33AT3 from ON Semiconductor is a unidirectional 600 W peak power TVS diode designed for transient overvoltage protection in DC power rails and signal lines. It features a 33 V working peak reverse voltage (VRWM), 40.6 V minimum breakdown voltage (VBR) at 1.0 mA, 53.3 V clamping voltage (VC) at 11.3 A peak pulse current (IPP), and <1.0 ns response time. It is used in industrial power supplies to suppress ESD and lightning-induced surges.
For engineers reviewing the 1SMB33AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 10/1000 µs surge, UL 497B certification for isolated loop protection, low leakage (<5.0 µA above 10 V), and SMB package compatibility with automated SMT assembly.
Technical Context
The 1SMB33AT3 operates as a Zener-based transient voltage suppressor, leveraging avalanche breakdown to clamp fast-rising transients. Its unidirectional configuration provides reverse-biased protection only, requiring correct polarity placement across protected nodes.
It delivers 600 W peak pulse power per 1 ms 10/1000 µs waveform, with thermal resistance of 226 °C/W (junction-to-ambient) and 40 °C/W (junction-to-lead), enabling robust surge handling in compact SMB packages. Clamping occurs at 53.3 V under 11.3 A IPP, with typical junction capacitance of 510 pF at 0 V bias and 1 MHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 33 V - Maximum continuous reverse operating voltage before clamping begins; sets minimum system voltage margin. |
| VBR (min) | 40.6 V @ 1.0 mA - Guaranteed avalanche initiation threshold; ensures reliable turn-on during overvoltage events. |
| VC @ IPP | 53.3 V @ 11.3 A - Maximum clamped voltage during 600 W surge; defines worst-case stress on downstream circuitry. |
| IPP | 11.3 A - Peak pulse current supported at rated clamping voltage; determines surge energy absorption capability. |
| Response Time | <1.0 ns - Enables suppression of sub-nanosecond ESD transients before sensitive ICs experience overstress. |
| Leakage Current | <5.0 µA @ VRWM - Minimizes standby power loss and avoids false triggering in high-impedance circuits. |
| UL Recognition | UL 497B (QVGQ2) - Certified for isolated loop circuit protection; validates reliability in telecom and industrial interfaces. |
Pinout & Package
1SMB33AT3 is housed in an SMB (DO-214AA) surface-mount plastic package (Case 403A), featuring a cathode band marking for polarity identification. The package uses modified L-bend leads for enhanced solder joint reliability and supports reflow soldering at 260°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction | Connected to lower-potential side of protected line; enables bidirectional surge path only when paired with complementary devices. |
| Cathode | Current exit terminal during reverse-biased clamping | Connected to higher-potential side (e.g., VCC rail); defines unidirectional clamping direction and polarity-sensitive placement. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power | Handles IEC 61000-4-5 Level 4 surges (4 kV line-earth) without degradation in SMB footprint. |
| ESD rating >16 kV HBM | Provides intrinsic immunity to human-body-model ESD events without external shielding or layout mitigation. |
| Low zener impedance | Ensures stable clamping voltage across varying surge currents, reducing voltage overshoot on protected nodes. |
| Pb-free (RoHS-compliant) | Meets global environmental regulations and supports lead-free reflow profiles without reliability compromise. |
| Void-free Surmetic molding | Eliminates internal delamination risks during thermal cycling, enhancing long-term field reliability in automotive/industrial environments. |
Applications
| Industrial Power Supply Protection | Automotive ECUs |
|---|---|
Use Scenario: Protecting 24 V DC input rails in programmable logic controllers against load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VIN and GND to clamp positive-going surges exceeding 33 V. Use Value: Limits voltage to ≤53.3 V during 11.3 A transients, preventing damage to upstream rectifiers and downstream DC-DC controllers. | Use Scenario: Safeguarding CAN transceiver power pins in engine control units exposed to ISO 7637-2 Pulse 5a load dump events. IC Role / Device Role / Timing Role: Standoff device absorbing 600 W surges within 1 ms, coordinated with upstream fuse timing. Use Value: Maintains system uptime by surviving repetitive 12 V/24 V load dump spikes without parametric shift or failure. |
| Medical Equipment Interfaces | Telecom Line Cards |
Use Scenario: Shielding isolated RS-485 data lines in patient monitors from ESD and surge coupling via shared chassis ground. IC Role / Device Role / Timing Role: UL 497B-certified protector on secondary-side signal lines, ensuring compliance with IEC 60601-1 creepage requirements. Use Value: Prevents latch-up or burnout in isolated interface ICs while maintaining signal integrity up to 10 Mbps. | Use Scenario: Protecting Ethernet PHY power inputs in DSLAM line cards from lightning-induced common-mode surges on AC mains-derived supplies. IC Role / Device Role / Timing Role: Primary-level clamping device on +3.3 V or +5 V rails feeding PHY ICs, coordinated with MOVs on AC side. Use Value: Reduces MTBF risk by limiting transient energy transferred to sensitive analog front-end circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33A | Same VRWM (33 V) and VC (53.3 V), but rated for 600 W with 10/1000 µs waveform; identical SMB package. | No functional difference in clamping behavior; validated for same IEC 61000-4-5 surge classes. | Select SMBJ33A if sourcing from manufacturers with broader second-source availability or specific qualification requirements. |
| 1.5SMC33A | Higher package thermal mass (SMC vs SMB); 600 W rating with 10/1000 µs, but larger footprint (7.11 × 6.22 mm vs 4.32 × 3.56 mm). | Preferred where board space allows and higher thermal inertia improves long-term surge endurance under repeated events. | Choose 1.5SMC33A when PCB layout permits larger footprint and thermal derating margins are critical for high-reliability deployments. |
Compared with SMBJ33A and 1.5SMC33A, the 1SMB33AT3 offers identical electrical protection performance in the smallest standardized SMB outline, enabling higher component density and lower assembly cost in space-constrained industrial and telecom designs.
Availability
1SMB33AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive ECUs, medical equipment interfaces, and telecom line cards requiring stable component supply and UL 497B-certified surge protection.
Supply support for 1SMB33AT3 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
ON Semiconductor (now onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and consumer markets.
The 1SMB33AT3 belongs to the SMB series of unidirectional TVS diodes, engineered for high-energy transient suppression in harsh environments-designed to protect voltage-sensitive components in communication systems, automotive electronics, and industrial controls.
FAQ
What is the maximum clamping voltage of the 1SMB33AT3 under surge conditions?
The 1SMB33AT3 has a maximum clamping voltage (VC) of 53.3 V when subjected to its rated peak pulse current (IPP) of 11.3 A, measured using the standard 10/1000 µs double-exponential waveform. This value is guaranteed across temperature and ensures downstream circuitry remains below destructive voltage thresholds during transient events. The 1SMB33AT3 maintains this clamping performance consistently due to its low zener impedance and optimized junction design.
Is the 1SMB33AT3 RoHS-compliant and lead-free?
Yes, the 1SMB33AT3 is Pb-free and RoHS-compliant, indicated by the "G" suffix in its full ordering code (1SMB33AT3G). It meets JEDEC J-STD-020 moisture sensitivity level 1 and supports standard lead-free reflow profiles up to 260°C for 10 seconds. The 1SMB33AT3 uses ON Semiconductor's void-free Surmetic molding compound, ensuring mechanical integrity and thermal reliability without lead-based materials.
Does the 1SMB33AT3 meet UL safety standards?
Yes, the 1SMB33AT3 carries UL 497B recognition (File #E210057, Category QVGQ2) for isolated loop circuit protection. This certification covers rigorous testing including strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge performance-validating its suitability for safety-critical telecom and industrial interfaces. The 1SMB33AT3 is not just compliant but specifically listed under UL's protector classification, unlike many competitors with only flammability-only recognition.
What is the thermal resistance of the 1SMB33AT3, and how does it affect power handling?
The 1SMB33AT3 has a junction-to-ambient thermal resistance (RJA) of 226 °C/W and junction-to-lead resistance (RJL) of 40 °C/W, measured on FR-4 board with ON Semiconductor's recommended footprint. These values define its ability to dissipate heat during repetitive surges: at 25°C ambient, it sustains 0.55 W DC power, derating linearly above 25°C. The 1SMB33AT3 relies on short-duration pulse operation (not continuous dissipation) for its 600 W peak rating, making thermal design focused on PCB copper area and lead thermal mass rather than heatsinking.
Can the 1SMB33AT3 be used for bidirectional transient protection?
No, the 1SMB33AT3 is strictly unidirectional and must be used with correct polarity-cathode to the higher-potential node (e.g., VCC). For bidirectional protection, ON Semiconductor offers the 1SMB33CAT3 variant (not the 1SMB33AT3). Using the 1SMB33AT3 in reverse-biased configurations outside its specified VRWM will not provide clamping and may result in catastrophic failure. Always verify polarity alignment in schematics and layout for the 1SMB33AT3 to ensure intended protection behavior.
1SMB33AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- -
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- -
- Unidirectional Channels:
- -
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- -
- Voltage - Breakdown (Min):
- -
- Voltage - Clamping (Max) @ Ipp:
- -
- Current - Peak Pulse (10/1000µs):
- -
- Power - Peak Pulse:
- -
- Power Line Protection:
- -
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
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- Grade:
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- Qualification:
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- Mounting Type:
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- Supplier Device Package:
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1SMB33AT3 FAQ
1.How can I place an order for 1SMB33AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB33AT3 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 1SMB33AT3 reliable?
The price and inventory of 1SMB33AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB33AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB33AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB33AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB33AT3?
1SMB33AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB33AT3 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 1SMB33AT3?
For technical support, including 1SMB33AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB33AT3 requirements.
6.How does Aetrix verify that 1SMB33AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB33AT3 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 1SMB33AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB33AT3?
All 1SMB33AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB33AT3, 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 1SMB33AT3 part is unused and in its original packaging.
Return procedure for 1SMB33AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB33AT3 Tags
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