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onsemi 1SMB22AT3
- Part No.:
- 1SMB22AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB22AT3.pdf
- Description:
- TVS DIODE 22VWM 35.5VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:4,309
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Product details
Overview
1SMB22AT3 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 22 V working peak reverse voltage (VRWM), 25.65 V nominal Zener breakdown voltage (VBR) at 1.0 mA test current, and clamps to ≤35.5 V at 16.9 A peak pulse current (IPP), with <1.0 ns response time and <5.0 µA leakage above 10 V. It is widely deployed in automotive power supplies and industrial control I/O interfaces.
For engineers reviewing the 1SMB22AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to system operating voltage, surge current handling under 1 ms pulses, UL 497B certification for isolated loop protection, and SMB package thermal performance in high-density PCB layouts.
Technical Context
The 1SMB22AT3 operates as a voltage-clamping transient suppressor in parallel with protected circuitry, leveraging avalanche breakdown to shunt surge energy away from sensitive components. Its low zener impedance and fast <1.0 ns response ensure minimal overshoot during ESD or lightning-induced transients.
It is rated for 600 W non-repetitive peak pulse power (10/1000 µs waveform), supports 100 A forward surge current (8.3 ms half-sine), and maintains stable clamping across −65°C to +150°C junction temperature range. Thermal resistance from junction-to-lead is 40°C/W, enabling reliable operation on FR-4 boards with minimum recommended footprint.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 22 V - Maximum continuous reverse operating voltage before clamping begins; must exceed system DC rail voltage. |
| VBR (min/typ/max) | 24.4 / 25.65 / 26.9 V @ 1.0 mA - Ensures predictable turn-on threshold with tight tolerance for consistent protection level. |
| VC @ IPP | ≤35.5 V @ 16.9 A - Clamping voltage under full 600 W surge; defines maximum stress seen by downstream ICs. |
| PPK | 600 W @ 1 ms - Peak transient energy absorption capability; validated per 10/1000 µs waveform standard. |
| IR @ VRWM | ≤5.0 µA - Low leakage preserves efficiency in battery-powered or high-impedance sensing circuits. |
| Response Time | <1.0 ns - Enables suppression of nanosecond-scale ESD events before damage occurs to CMOS inputs. |
| ESD Rating | Class 3 (>16 kV HBM) - Meets stringent electrostatic discharge immunity requirements for automotive and industrial environments. |
| UL Recognition | UL 497B QVGQ2 - Certified for isolated loop circuit protection, including strike voltage, endurance, and dielectric withstand tests. |
Pinout & Package
Package: SMB (Case 403A), surface-mount, void-free thermosetting plastic with modified L-bend leads and cathode polarity band. Mounting position is unrestricted; max soldering temperature is 260°C for 10 seconds.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction or surge shunting | Connected to lower-potential side (e.g., ground or return path); forms low-impedance surge path when device avalanches. |
| Cathode | Current exit terminal during reverse-biased clamping | Connected to protected line (e.g., 24 V rail); voltage at this node is clamped to ≤35.5 V during transients. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power rating | Handles high-energy surges (e.g., ISO 7637-2 Pulse 5a) without degradation in automotive power systems. |
| Low clamping ratio (VC/VBR ≈ 1.39) | Minimizes overvoltage stress on downstream components while maintaining robust margin above VRWM. |
| UL 497B recognition (QVGQ2) | Validates suitability for safety-critical isolated loop protection in medical and industrial communication interfaces. |
| Pb-free (G suffix) and RoHS-compliant | Enables compliance with global environmental regulations and lead-free reflow assembly processes. |
| Thermal resistance RJL = 40°C/W | Supports sustained power dissipation on standard FR-4 PCBs using ON Semiconductor's recommended 1-in² copper pad layout. |
Applications
| Automotive Power Supply Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: Suppresses load dump transients (ISO 7637-2 Pulse 5) on 24 V vehicle ECUs and body control modules. IC Role / Device Role / Timing Role: Voltage-clamping TVS placed between battery rail and regulator input to limit voltage excursion to ≤35.5 V. Use Value: Prevents permanent damage to LDOs and microcontrollers during 120 V/500 ms load dump events. |
Use Scenario: Protects 24 V digital input channels in programmable logic controllers against field-wiring induced surges. IC Role / Device Role / Timing Role: Parallel-connected transient suppressor on each optocoupler input line, clamping within 1 ns. Use Value: Maintains signal integrity and prevents false triggering or latch-up in isolated input stages. |
| Medical Equipment Isolated Interface | Telecom Power Feeding Protection |
Use Scenario: Shields RS-485 transceivers and isolated ADC front-ends in patient-monitoring devices from ESD and surge coupling. IC Role / Device Role / Timing Role: UL 497B-certified TVS on secondary-side data/power lines to meet IEC 60601-1 creepage and isolation requirements. Use Value: Ensures continued safe operation during 15 kV contact ESD events without compromising galvanic isolation. |
Use Scenario: Guards PoE (Power over Ethernet) midspan injectors against lightning-induced common-mode surges on 48 V DC feed lines. IC Role / Device Role / Timing Role: Unidirectional clamp on DC output rail, coordinated with upstream GDT and series impedance for multi-stage protection. Use Value: Limits voltage to <36 V during 10/1000 µs surges, preventing MOSFET gate oxide rupture in DC-DC controllers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ22A | Same SMB package, identical VRWM (22 V) and VC (35.5 V), but rated for 600 W with tighter VBR tolerance (24.4–26.9 V vs. 24.4–26.9 V); no UL 497B listing. | Lacks UL 497B certification; unsuitable for medical isolated loop or telecom safety-critical designs requiring recognized protector status. | Select SMBJ22A only when UL recognition is not required and cost optimization is prioritized over regulatory compliance. |
| 1.5SMC22A | Higher 1500 W peak power rating, same VRWM and VBR range, but larger SMC (DO-214AB) package (7.11 × 6.22 mm vs. SMB's 4.32 × 2.62 mm). | Requires more PCB area and has higher parasitic inductance; less effective for ultrafast ESD where layout inductance dominates overshoot. | Choose 1.5SMC22A only when system-level surge testing exceeds 600 W requirements and board space permits larger footprint. |
Compared with SMBJ22A and 1.5SMC22A, the 1SMB22AT3 uniquely combines UL 497B recognition, SMB-size compactness, and verified 600 W surge capability-making it the preferred choice for space-constrained, safety-certified industrial and automotive applications where regulatory validation is mandatory.
Availability
1SMB22AT3 is available at Aetrix Electronics and suitable for automotive power supply protection, industrial PLC I/O conditioning, and medical isolated interface designs requiring stable component supply, long-term lifecycle support, and traceable Pb-free sourcing.
Supply support for 1SMB22AT3 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 part of onsemi) is a global semiconductor manufacturer specializing in power management, analog, sensor, and discrete solutions for automotive, industrial, and cloud power applications.
The 1SMB22AT3 belongs to the SMB-series transient voltage suppressor family, engineered specifically for high-reliability, high-surge industrial and automotive systems requiring UL-recognized, surface-mount overvoltage protection with minimal PCB footprint.
FAQ
What is the clamping voltage of the 1SMB22AT3 under maximum surge conditions?
The 1SMB22AT3 clamps to a maximum of 35.5 V at its rated peak pulse current of 16.9 A (10/1000 µs waveform). This value is guaranteed across temperature and process variation, and defines the upper voltage limit imposed on protected circuitry during transient events. The 1SMB22AT3 achieves this with low dynamic impedance, ensuring consistent clamping performance even under repeated surges.
Does the 1SMB22AT3 have UL 497B certification, and what does that mean for my design?
Yes, the 1SMB22AT3 carries UL 497B recognition under file QVGQ2, validating its use in isolated loop circuit protection. This certification confirms successful completion of strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge testing-critical for medical, telecom, and industrial systems requiring certified surge protection. The 1SMB22AT3 is among the few SMB-sized TVS diodes with this specific listing.
What is the thermal resistance and power derating behavior of the 1SMB22AT3?
The 1SMB22AT3 has a junction-to-lead thermal resistance (RJL) of 40°C/W and a junction-to-ambient resistance (RJA) of 226°C/W on standard FR-4. Its DC power dissipation derates linearly above 75°C ambient: 3.0 W at 75°C, decreasing by 25 mW/°C. For reliable long-term operation, maintain PCB copper area per ON Semiconductor's Case 403A footprint recommendation to sustain thermal performance.
How does the 1SMB22AT3 compare to bidirectional TVS diodes in surge protection applications?
The 1SMB22AT3 is unidirectional and optimized for DC rail protection where polarity is fixed (e.g., 24 V supply lines), offering lower leakage (<5.0 µA) and tighter VBR tolerance than equivalent bidirectional parts. Bidirectional variants like 1SMB22CAT3 are needed only for AC or floating signal lines subject to voltage reversals; using them on DC rails adds unnecessary leakage and reduces clamping margin. The 1SMB22AT3 delivers superior performance in polarity-defined applications.
Is the 1SMB22AT3 suitable for automotive load dump protection per ISO 7637-2?
Yes, the 1SMB22AT3 is routinely deployed for ISO 7637-2 Pulse 5a (load dump) suppression in 24 V automotive systems. With its 600 W peak power rating, 35.5 V clamping voltage, and ability to handle 100 A forward surge current (8.3 ms), it meets the energy absorption and voltage limiting requirements for protecting downstream regulators and microcontrollers. Layout best practices-short traces, direct grounding-must be followed to minimize inductive overshoot.
1SMB22AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 22V
- Voltage - Breakdown (Min):
- 24.4V
- Voltage - Clamping (Max) @ Ipp:
- 35.5V
- Current - Peak Pulse (10/1000µs):
- 16.9A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 730pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB22AT3 FAQ
1.How can I place an order for 1SMB22AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB22AT3 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 1SMB22AT3 reliable?
The price and inventory of 1SMB22AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB22AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB22AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB22AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB22AT3?
1SMB22AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB22AT3 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 1SMB22AT3?
For technical support, including 1SMB22AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB22AT3 requirements.
6.How does Aetrix verify that 1SMB22AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB22AT3 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 1SMB22AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB22AT3?
All 1SMB22AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB22AT3, 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 1SMB22AT3 part is unused and in its original packaging.
Return procedure for 1SMB22AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB22AT3 Tags
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