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onsemi 1SMB24AT3
- Part No.:
- 1SMB24AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB24AT3.pdf
- Description:
- TVS DIODE 24VWM 38.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:7,550
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Product details
Overview
1SMB24AT3 from onsemi is a unidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 24 V working peak reverse voltage (VRWM), 29.5 V maximum clamping voltage (VC) at 15.4 A peak pulse current (IPP), and sub-1 ns response time. It is used in power supply input stages, automotive ECUs, and industrial I/O interfaces to absorb ESD and lightning-induced surges.
For engineers reviewing the 1SMB24AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin vs. system DC rail, VC headroom relative to IC absolute maximum ratings, UL 497B certification for isolated loop protection, and SMB package thermal performance under repetitive surge conditions.
Technical Context
The 1SMB24AT3 operates as a Zener-based avalanche clamp, triggered when reverse voltage exceeds its 26.7–29.5 V breakdown range (VBR @ IT = 1 mA). Its low zener impedance and fast junction response enable effective suppression of 8/20 µs and 10/1000 µs transients without significant overshoot-provided layout minimizes trace inductance.
It is rated for 600 W non-repetitive peak power (1 ms pulse), with thermal derating to 0.55 W at TA = 25°C and 3.0 W at TL = 75°C. The device meets Class 3 ESD immunity (>16 kV HBM) and UL 497B recognition for isolated loop circuit protection, confirming suitability for telecom and industrial safety-critical interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 24 V - Maximum continuous reverse operating voltage before clamping begins; must exceed system DC rail by ≥10% to avoid leakage-induced heating. |
| VBR (min/typ/max) | 26.7 / 28.1 / 29.5 V @ 1 mA - Confirmed avalanche onset range; ensures predictable turn-on across temperature and unit variation. |
| VC @ IPP | 38.9 V @ 15.4 A - Clamped voltage during 10/1000 µs surge; defines worst-case stress on downstream components. |
| PPK | 600 W @ 1 ms - Peak surge energy handling capacity; validated per IEC 61000-4-5 Level 4 compliance testing. |
| IR @ VRWM | 5.0 µA max - Low leakage preserves efficiency in high-impedance bias networks and battery-backed circuits. |
| Response Time | <1.0 ns - Junction-limited switching speed; enables protection of high-speed interfaces without signal distortion. |
| UL Recognition | UL 497B QVGQ2 - Certified for use in primary-side isolated loop protectors, including telecom and process control systems. |
Pinout & Package
Package: SMB (Case 403A), surface-mount, void-free thermosetting plastic with modified L-bend leads. Cathode indicated by polarity band. Mounting position unrestricted; compatible with standard reflow profiles (260°C/10 s max).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during clamping | Connected to protected line (e.g., +12 V rail); carries full surge current to ground path. |
| Cathode | Clamp reference node | Connected to system ground or low-impedance return; defines clamping threshold relative to GND. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak power rating | Supports IEC 61000-4-5 Level 4 (4 kV line-to-ground) surge immunity without derating in compact SMB footprint. |
| UL 497B recognition | Validated for use in certified isolated loop protectors-eliminates need for additional safety agency retesting in end equipment. |
| ESD Class 3 (>16 kV HBM) | Meets IEC 61000-4-2 Level 4 requirements for user-accessible ports without external ESD staging. |
| Low clamping ratio (VC/VBR ≈ 1.38) | Minimizes voltage overshoot during fast transients, reducing risk of latch-up or gate oxide damage in downstream MOSFETs/ICs. |
| Pb-free (G suffix) and RoHS compliant | Enables direct drop-in replacement in legacy designs transitioning to lead-free assembly without requalification. |
Applications
| Industrial Power Supply Input | 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: Unidirectional TVS clamp placed between input rail and chassis ground to limit transient voltage to ≤40 V. Use Value: Prevents damage to upstream rectifier diodes and downstream DC/DC controller ICs during 12 V system load dump events (up to 60 V/100 ms). |
Use Scenario: CAN bus physical layer interface in body control module subjected to ESD and coupled noise from adjacent solenoid drivers. IC Role / Device Role / Timing Role: Secondary-level TVS on VCC line feeding CAN transceiver, supplementing primary front-end protection. Use Value: Absorbs >16 kV contact ESD per IEC 61000-4-2 while maintaining <100 ns response to preserve CAN bit timing integrity. |
| Medical Equipment Sensor Interface | Telecom Line Card Protection |
Use Scenario: 24 V auxiliary supply rail powering isolated analog sensor front-ends in patient-monitoring devices. IC Role / Device Role / Timing Role: UL 497B-certified TVS on secondary-side isolated rail to meet IEC 60601-1 creepage/clearance and surge immunity requirements. Use Value: Enables single-device compliance with both electrical safety (UL) and EMC (IEC 61000-4-5) standards for Class II medical equipment. |
Use Scenario: Protection of -48 V DC power feed on telecom line card supporting multiple subscriber lines. IC Role / Device Role / Timing Role: Primary overvoltage clamp on central office power distribution bus, coordinated with gas discharge tube (GDT) front-end. Use Value: Provides low-clamp, fast-response backup to GDT during fast-rising transients (e.g., induced lightning), limiting voltage to <40 V before GDT fully fires. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24A | Same SMB package, identical VRWM (24 V) and VC (38.9 V), but rated for 600 W per JEDEC JESD22-A114 (vs. onsemi's proprietary test method). | No UL 497B recognition; limited to non-safety-critical industrial use where agency certification is not mandated. | Select when cost sensitivity outweighs UL certification needs and design uses JEDEC-aligned test standards. |
| 1.5SMC24A | Larger SMC package (7.1 × 6.2 mm vs. SMB's 4.6 × 3.6 mm); same 24 V VRWM but higher thermal mass allows 10% higher average power dissipation. | Better suited for high-duty-cycle surge environments (e.g., motor drive controls) where SMB thermal limits may be exceeded. | Select when PCB space permits larger footprint and application requires sustained surge handling beyond 1×/minute repetition rate. |
Compared with SMBJ24A and 1.5SMC24A, the 1SMB24AT3 uniquely combines UL 497B certification, SMB-size board area efficiency, and verified 600 W surge capability-making it optimal for space-constrained, safety-certified industrial and telecom power rails.
Availability
1SMB24AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, medical sensor interfaces, and telecom line cards requiring stable component supply and long-term lifecycle support.
Supply support for 1SMB24AT3 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The 1SMB24AT3 belongs to the SMB series of unidirectional TVS diodes, engineered specifically for high-energy transient suppression in space-constrained, safety-certified applications such as industrial automation and telecom infrastructure.
FAQ
What is the clamping voltage of the 1SMB24AT3 under maximum surge conditions?
The 1SMB24AT3 exhibits a maximum clamping voltage (VC) of 38.9 V when subjected to its rated peak pulse current of 15.4 A (10/1000 µs waveform). This value is measured at TJ = 25°C and represents the worst-case voltage seen by downstream circuitry during a full-power transient event. Designers must ensure all protected components have absolute maximum ratings exceeding 38.9 V to prevent damage.
Does the 1SMB24AT3 meet UL 497B requirements for isolated loop protection?
Yes, the 1SMB24AT3 carries UL 497B recognition under file #E210057 in the QVGQ2 category for protectors. This certification validates its performance in isolated loop applications-including dielectric withstand, strike voltage breakdown, and endurance conditioning tests-making it suitable for telecom and industrial isolation barriers without requiring additional system-level safety retesting.
How does the 1SMB24AT3 differ from bidirectional TVS diodes like the 1SMB24AT3-BI?
The 1SMB24AT3 is unidirectional and optimized for DC-biased lines (e.g., +24 V power rails), providing low leakage (<5 µA) and precise clamping only in reverse bias. Bidirectional variants (e.g., 1SMB24AT3-BI) clamp symmetrically for AC-coupled signals like data lines but exhibit higher leakage and reduced DC blocking capability-making the 1SMB24AT3 the correct choice for power rail protection.
What is the thermal resistance and power derating behavior of the 1SMB24AT3?
The 1SMB24AT3 has a junction-to-ambient thermal resistance (RJA) of 226°C/W and junction-to-lead resistance (RJL) of 40°C/W. Its DC power dissipation derates linearly above 25°C (0.55 W at TA = 25°C → 0 W at ~150°C) and above 75°C for lead-temperature-limited operation (3.0 W at TL = 75°C → 0 W at ~150°C). These values assume ON Semiconductor's recommended minimum footprint on FR-4 board.
Can the 1SMB24AT3 replace older SMA-package TVS diodes in existing designs?
No-the 1SMB24AT3 uses the SMB package (4.6 × 3.6 mm), which is physically larger than SMA (4.3 × 2.6 mm) and incompatible with SMA footprints. While both packages share similar mounting orientation, the 1SMB24AT3 requires PCB pad revision due to increased body width and lead spacing. Migration requires layout update and thermal validation, though electrical characteristics remain functionally equivalent.
1SMB24AT3 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):
- 24V
- Voltage - Breakdown (Min):
- 26.7V
- Voltage - Clamping (Max) @ Ipp:
- 38.9V
- Current - Peak Pulse (10/1000µs):
- 15.4A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 675pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB24AT3 FAQ
1.How can I place an order for 1SMB24AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB24AT3 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 1SMB24AT3 reliable?
The price and inventory of 1SMB24AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB24AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB24AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB24AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB24AT3?
1SMB24AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB24AT3 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 1SMB24AT3?
For technical support, including 1SMB24AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB24AT3 requirements.
6.How does Aetrix verify that 1SMB24AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB24AT3 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 1SMB24AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB24AT3?
All 1SMB24AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB24AT3, 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 1SMB24AT3 part is unused and in its original packaging.
Return procedure for 1SMB24AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB24AT3 Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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ESD5Z3.3T1G
onsemi
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D5V0H1B2LP-7B
Diodes Incorporated
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D5V0P1B2LP-7B
Diodes Incorporated
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DESD5V0U1BA-7
Diodes Incorporated
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ESD5Z5.0T1G
onsemi
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DESD5V0U1BB-7
Diodes Incorporated
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D12V0L1B2LP-7B
Diodes Incorporated
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PESD2V0Y1BSFYL
Nexperia USA Inc.
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DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
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D5V0L1B2WS-7
Diodes Incorporated
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