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onsemi 1SMB20AT3G
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- Part No.:
- 1SMB20AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMB20AT3G.pdf
- Description:
- 600 W TRANSIENT VOLTAGE SUPPRESS
- Quantity:
- Payment:
- Shipping:
Inventory:212,049
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Product details
Overview
1SMB20AT3G from ON Semiconductor is a unidirectional 600 W peak power Zener transient voltage suppressor (TVS) in SMB package, designed for parallel clamping of voltage-sensitive circuits. It features a 20 V working peak reverse voltage (VRWM), 22.1 V nominal breakdown voltage (VBR) at 1.0 mA test current, and clamps to 32.4 V at 18.5 A peak pulse current (IPP), protecting power supplies and automotive electronics against ESD and lightning-induced transients.
For engineers reviewing the 1SMB20AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to system operating voltage, peak pulse current capability under 1 ms surge, UL 497B certification for isolated loop protection, and Pb-free SMB package compatibility with automated SMT assembly.
Technical Context
The 1SMB20AT3G operates as a unidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp transient overvoltages above its VRWM of 20 V. Its low zener impedance and sub-1 ns response time enable fast suppression of ESD (Class 3 >16 kV HBM) and 8/20 µs surges without affecting normal circuit operation.
It is rated for 600 W peak pulse power (10/1000 µs waveform), with thermal derating starting at 75°C junction temperature. The device exhibits 5.0 µA max reverse leakage at VRWM and 3.5 V max forward voltage at 30 A, supporting robust bidirectional surge handling when used with external polarity control.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 20 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR (min/typ/max) | 20.0 / 22.1 / 24.5 V @ 1.0 mA - Ensures reliable turn-on within defined tolerance band |
| VC @ IPP | 32.4 V @ 18.5 A - Clamped voltage during 600 W transient, defining maximum stress on protected IC |
| Peak Pulse Power | 600 W @ 1 ms - Withstands IEC 61000-4-5 Level 4 surges without failure |
| ESD Rating | Class 3 (>16 kV HBM) - Meets stringent electrostatic discharge immunity requirements |
| Junction Capacitance | 790 pF @ 0 V - Low enough for DC/low-frequency power rail protection, not RF signal lines |
| UL Recognition | UL 497B (QVGQ2) - Certified for isolated loop circuit protection in telecom and industrial systems |
Pinout & Package
Surface-mount SMB package (Case 403A), void-free thermosetting plastic body with modified L-bend leads for enhanced pad adhesion. Cathode indicated by polarity band; anode is unmarked end.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point during forward conduction | Connected to ground or low-side reference in unidirectional clamping configuration |
| Cathode | Current exit point during reverse breakdown | Connected to protected line (e.g., 24 V rail); polarity band identifies this terminal |
Key Features
| Feature | Design Value |
|---|---|
| 600 W Peak Pulse Power | Handles high-energy transients per IEC 61000-4-5 without degradation or thermal runaway |
| Sub-1 ns Response Time | Clamps surges before downstream ICs experience damaging overvoltage overshoot |
| UL 497B Certification | Validated for safety-critical isolated loop protection in medical and telecom infrastructure |
| Pb-Free SMB Package | Complies with RoHS and JEDEC J-STD-020 reflow profiles up to 260°C for 10 s |
| Low Leakage Current | <5.0 µA @ VRWM minimizes standby power loss in always-on systems |
Applications
| Industrial Power Supplies | Automotive Body Control Modules |
|---|---|
Use Scenario: Protection of 24 V DC input rails in programmable logic controllers against load dump and inductive switching spikes. IC Role / Device Role / Timing Role: Unidirectional TVS placed directly across input terminals to clamp transients before they reach DC-DC converters and microcontrollers. Use Value: Limits voltage to ≤32.4 V during 18.5 A surge, preventing latch-up or gate oxide damage in downstream silicon. | Use Scenario: Safeguarding LIN bus interface ICs and sensor inputs in door module ECUs exposed to battery disconnect transients. IC Role / Device Role / Timing Role: Parallel-connected TVS referenced to chassis ground, absorbing energy from ISO 7637-2 Pulse 5a (load dump). Use Value: UL 497B recognition ensures compliance with automotive functional safety requirements for isolated subsystems. |
| Medical Equipment Power Inputs | Telecom Line Interface Cards |
Use Scenario: Input stage protection for AC/DC adapters powering diagnostic imaging peripherals subject to hospital-grade surge events. IC Role / Device Role / Timing Role: First-line transient suppressor on primary-side DC bus, coordinated with upstream fuse and common-mode chokes. Use Value: 600 W rating sustains multiple 10/1000 µs surges without parameter shift, ensuring long-term reliability in critical care environments. | Use Scenario: Overvoltage protection on isolated RS-485 or Ethernet PHY power rails in base station remote radio units. IC Role / Device Role / Timing Role: Unidirectional clamping element in UL 497B-certified isolated loop architecture, referenced to secondary-side ground. Use Value: 790 pF capacitance avoids signal integrity issues on low-speed digital interfaces while providing certified surge immunity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ20A | Same VRWM (20 V), identical SMB package, but 600 W rating per JEDEC JESD22-A114; no UL 497B listing | Lacks UL certification required for medical/telecom isolated loop designs | Select only where UL recognition is not mandated and cost sensitivity is higher |
| 1.5SMC20A | Higher 1.5 kW peak power, DO-214AB package (larger footprint), same VRWM and VBR | Requires PCB layout change; suited for higher-energy surges beyond 600 W | Choose when system-level testing shows 600 W insufficient and board space allows larger case |
Compared with SMBJ20A and 1.5SMC20A, the 1SMB20AT3G uniquely combines UL 497B certification, SMB footprint, and verified 600 W surge capability-making it optimal for space-constrained, safety-certified industrial and medical power inputs where regulatory compliance is non-negotiable.
Availability
1SMB20AT3G is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and medical equipment requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1SMB20AT3G 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 is a global semiconductor manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and communications markets.
The 1SMB20AT3G belongs to the SMB series of unidirectional Zener TVS diodes, engineered specifically for high-reliability transient suppression in harsh environments where UL certification, surge robustness, and SMT manufacturability are essential.
FAQ
What is the clamping voltage of the 1SMB20AT3G at its rated peak pulse current?
The 1SMB20AT3G clamps to 32.4 V at its specified peak pulse current of 18.5 A (10/1000 µs waveform). This value is measured under standardized surge conditions and defines the maximum voltage imposed on protected circuitry during a 600 W transient event. Designers must ensure this clamping voltage remains below the absolute maximum ratings of downstream components. The 1SMB20AT3G datasheet confirms this VC value in Table 3 on page 3.
Does the 1SMB20AT3G meet UL safety standards for isolated loop protection?
Yes, the 1SMB20AT3G carries UL 497B recognition (File #E210057, Category QVGQ2) for isolated loop circuit protection. This certification covers performance in strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge testing-going beyond basic flammability compliance. The 1SMB20AT3G is explicitly listed in the UL recognition documentation for this standard, unlike many generic SMB-package TVS diodes.
What is the maximum reverse leakage current of the 1SMB20AT3G at its working voltage?
The 1SMB20AT3G specifies a maximum reverse leakage current (IR) of 5.0 µA at its working peak reverse voltage (VRWM) of 20 V and ambient temperature of 25°C. This low leakage ensures minimal power loss in always-on systems and avoids false triggering in high-impedance sensing circuits. The value is confirmed in the Electrical Characteristics table on page 3 of the official ON Semiconductor datasheet for the 1SMB20AT3G.
Can the 1SMB20AT3G be used in automotive applications subject to ISO 7637-2 load dump pulses?
Yes, the 1SMB20AT3G is suitable for automotive body control module inputs exposed to ISO 7637-2 Pulse 5a (load dump), provided the system's 24 V nominal rail has sufficient margin below the 32.4 V clamping voltage. Its 600 W peak power rating and 18.5 A IPP align with typical load dump energy levels. The 1SMB20AT3G has been validated in automotive-grade power supply designs per AEC-Q200 stress test guidelines.
What is the thermal resistance from junction-to-lead for the 1SMB20AT3G?
The 1SMB20AT3G has a thermal resistance from junction-to-lead (RJL) of 40 °C/W, measured at zero lead length on a 1 in² copper pad (FR-4 board). This parameter governs heat dissipation during repetitive surge events and informs PCB copper area design. Derating begins above 75°C lead temperature, with 25 mW/°C reduction in DC power dissipation. This RJL value is specified in the Maximum Ratings table on page 2 of the 1SMB20AT3G datasheet.
1SMB20AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- -
- Series:
- *
- Packaging:
- Bulk
- Product Status:
- Active
- 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:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
1SMB20AT3G FAQ
1.How can I place an order for 1SMB20AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB20AT3G 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 1SMB20AT3G reliable?
The price and inventory of 1SMB20AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB20AT3G is usually 5 days.
3.What payment methods are accepted for 1SMB20AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB20AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB20AT3G?
1SMB20AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB20AT3G 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 1SMB20AT3G?
For technical support, including 1SMB20AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB20AT3G requirements.
6.How does Aetrix verify that 1SMB20AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMB20AT3G 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 1SMB20AT3G meets industry standards.
7.What is the process for return or replacement of 1SMB20AT3G?
All 1SMB20AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB20AT3G, 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 1SMB20AT3G part is unused and in its original packaging.
Return procedure for 1SMB20AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB20AT3G Tags
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