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onsemi 1SMB70AT3
- Part No.:
- 1SMB70AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMB70AT3.pdf
- Description:
- TVS DIODE 70V 113V SMB
- Quantity:
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Inventory:6,379
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Product details
Overview
1SMB70AT3 from ON Semiconductor is a unidirectional 600 W peak power Zener transient voltage suppressor (TVS) designed for parallel overvoltage protection of sensitive electronics. It features a 70 V working peak reverse voltage (VRWM), 113 V maximum clamping voltage at 5.3 A peak pulse current, and sub-1 ns response time. It is used in industrial power supplies to safeguard rectifier stages and DC bus lines against lightning-induced surges.
For engineers reviewing the 1SMB70AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system DC bus voltage, VC < IC absolute maximum rating, low leakage (<5 µA @ 70 V), UL 497B recognition for isolated loop protection, and SMB package compatibility with high-density PCB layouts.
Technical Context
The 1SMB70AT3 operates as a silicon avalanche diode with Zener breakdown behavior, triggered when reverse voltage exceeds its 77.8 V minimum breakdown voltage at 1 mA test current. Its clamping action limits transient energy by diverting surge current away from protected circuitry while maintaining voltage below 113 V at 5.3 A.
It uses a single-junction planar construction in an SMB (DO-214AA) surface-mount package with cathode polarity band marking. Thermal performance is defined by 226 °C/W junction-to-ambient resistance on FR-4 board with minimum footprint, and it supports 100 A non-repetitive forward surge current per 8.3 ms half-sine pulse.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 70 V - Maximum continuous reverse operating voltage before clamping begins; must exceed system DC bus or signal line peak voltage. |
| VBR (min) | 77.8 V @ 1 mA - Guaranteed avalanche initiation threshold; ensures reliable turn-on above normal operating conditions. |
| VC @ IPP | 113 V @ 5.3 A - Maximum clamped voltage during 1 ms 600 W transient; defines worst-case stress on downstream components. |
| IPP | 5.3 A - Peak pulse current corresponding to 600 W dissipation; determines required upstream current-limiting impedance. |
| IR @ VRWM | 5.0 µA - Reverse leakage at rated working voltage; low enough to avoid measurable power loss or signal distortion in high-impedance circuits. |
| Response Time | <1.0 ns - Time from transient onset to clamping onset; enables protection of fast-edge digital and analog signals. |
| UL Recognition | UL 497B QVGQ2 - Certified for use in isolated loop telecom and industrial control protection circuits, not just flammability compliance. |
Pinout & Package
1SMB70AT3 is housed in an SMB (DO-214AA) surface-mount plastic package (Case 403A), featuring a modified L-bend leadform for enhanced pad adhesion and cathode polarity indicated by a band on the case body. Mounting orientation is unrestricted.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during clamping | Connected to ground or low-impedance return path; carries full surge current during transient events. |
| Cathode | Protected circuit node connection | Connected to the line or rail being protected (e.g., +48 V DC bus); voltage referenced to anode during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power | Handles IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) without failure when properly mounted with low-inductance layout. |
| ESD rating >16 kV HBM | Provides robust handling immunity during automated assembly and field service, reducing latent damage risk. |
| Low zener impedance | Ensures tight clamping voltage regulation across varying surge currents, minimizing voltage overshoot on protected nodes. |
| Pb-free SURMETIC™ package | Meets RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) for reflow compatibility. |
| AEC-Q101 qualified (SZ variant) | Validated for automotive under-hood environments including temperature cycling, mechanical shock, and humidity exposure. |
Applications
| Industrial Power Supply Protection | Telecom Line Interface |
|---|---|
Use Scenario: Protecting 48 V DC output rails in DIN-rail mounted AC/DC converters against load dump and lightning-induced surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between +48 V rail and chassis ground to clamp transients exceeding 70 V. Use Value: Limits voltage excursion to ≤113 V during 600 W surges, preventing damage to downstream DC-DC controllers and MOSFET gate drivers. |
Use Scenario: Shielding RS-485 transceivers connected to outdoor wiring in building automation systems. IC Role / Device Role / Timing Role: Cathode tied to data line (A/B), anode to ground; clamps common-mode surges induced on twisted-pair cabling. Use Value: UL 497B certification confirms suitability for isolated loop protection, enabling compliance with ANSI/TIA-568-C.2 requirements. |
| Automotive Body Control Module | Medical Equipment Input Stage |
Use Scenario: Safeguarding LIN bus transceivers and microcontroller I/O pins against battery reverse connection and jump-start transients. IC Role / Device Role / Timing Role: Mounted directly at connector entry point with minimal trace length to suppress sub-10 ns edge transients. Use Value: Sub-1 ns response time and low parasitic capacitance (260 pF) preserve signal integrity on 20 kbps LIN networks. |
Use Scenario: Protecting patient-connected ECG amplifier inputs from defibrillator discharge pulses and ESD events. IC Role / Device Role / Timing Role: Placed at front-end filter stage to limit transient energy before reaching precision instrumentation amplifiers. Use Value: 5 µA max leakage at 70 V prevents DC offset drift in high-gain, low-noise analog signal chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ70A | Same VRWM (70 V) and VC (113 V), but 400 W peak power rating and SMA package (smaller footprint, lower thermal mass). | Limited to lower-energy transients (IEC 61000-4-5 Level 3); unsuitable for 600 W surge duty cycles. | Select 1SMB70AT3 where sustained 600 W surge capability or higher thermal margin is required. |
| SMCJ70A | Same VRWM and VC, but 1500 W peak power rating and SMC package (larger footprint, higher thermal capacity). | Over-specified for 600 W applications; occupies 2.5× more PCB area and costs ~22% more. | Choose 1SMB70AT3 when space-constrained designs require optimal power density and cost efficiency. |
Compared with SMAJ70A and SMCJ70A, the 1SMB70AT3 delivers the precise 600 W surge rating in the smallest thermally adequate package, balancing PCB area, thermal performance, and cost for mid-tier industrial and telecom surge protection.
Availability
1SMB70AT3 is available at Aetrix Electronics and suitable for industrial power supplies, telecom infrastructure equipment, automotive control modules, and medical device input stages requiring stable component supply and long-term lifecycle support.
Supply support for 1SMB70AT3 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, sensor, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The 1SMB70AT3 belongs to the SMB-series unidirectional TVS family, engineered specifically for high-reliability, high-surge industrial and automotive applications where UL 497B certification, low clamping voltage, and robust thermal performance are critical.
FAQ
What is the maximum clamping voltage of the 1SMB70AT3 under standard surge conditions?
The 1SMB70AT3 has a maximum clamping voltage (VC) of 113 V when subjected to its rated peak pulse current of 5.3 A, measured using the 10/1000 µs waveform per IEC 61000-4-5. This value is guaranteed across temperature and represents the highest voltage seen at the protected node during a 600 W transient event. The 1SMB70AT3 maintains this clamping performance due to its low dynamic impedance and optimized junction design.
Is the 1SMB70AT3 suitable for bidirectional signal line protection?
No, the 1SMB70AT3 is a unidirectional TVS diode and is not suitable for bidirectional signal line protection such as RS-232 or USB data lines. It conducts only in reverse bias above VRWM and blocks forward current beyond its 3.5 V forward voltage rating. For bidirectional protection, ON Semiconductor offers the 1SMB70CAT3 (complementary version) or dedicated bidirectional families like SMBJ70CA. Using the 1SMB70AT3 on AC-coupled or dual-polarity lines risks forward conduction and potential failure.
Does the 1SMB70AT3 meet automotive qualification standards?
The base 1SMB70AT3 is not AEC-Q101 qualified; however, the SZ1SMB70AT3G variant is fully AEC-Q101 qualified and PPAP capable for automotive applications. Both share identical electrical specifications and SMB package dimensions, but the SZ-prefix part undergoes additional process controls, lot traceability, and stress testing per automotive requirements. For body control modules or infotainment systems requiring automotive-grade reliability, specify SZ1SMB70AT3G instead of 1SMB70AT3.
What is the junction-to-ambient thermal resistance of the 1SMB70AT3 on a standard PCB?
The 1SMB70AT3 has a junction-to-ambient thermal resistance (RJA) of 226 °C/W when mounted on an FR-4 board using ON Semiconductor's minimum recommended footprint (per Case 403A outline). This value assumes no copper pour or thermal vias. With 1 in² copper pad, RJA improves to 40 °C/W (junction-to-lead), enabling higher average power handling. Proper thermal layout is essential to sustain repeated 600 W surges without junction overheating.
How does the 1SMB70AT3 compare to the 1N6277A in terms of surge capability?
The 1SMB70AT3 provides 600 W peak pulse power in an SMB package, whereas the through-hole 1N6277A (DO-201AD) delivers 600 W in a larger package with higher thermal mass. Electrically, both share nearly identical VRWM (70 V), VBR (77.8 V min), and VC (113 V), but the 1SMB70AT3 offers superior board-level integration, lower profile, and Pb-free compliance. The 1SMB70AT3 is preferred for modern SMT production, while the 1N6277A remains viable for legacy through-hole designs or high-vibration environments requiring mechanical anchoring.
1SMB70AT3 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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1SMB70AT3 FAQ
1.How can I place an order for 1SMB70AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB70AT3 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 1SMB70AT3 reliable?
The price and inventory of 1SMB70AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB70AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB70AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB70AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB70AT3?
1SMB70AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB70AT3 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 1SMB70AT3?
For technical support, including 1SMB70AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB70AT3 requirements.
6.How does Aetrix verify that 1SMB70AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB70AT3 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 1SMB70AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB70AT3?
All 1SMB70AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB70AT3, 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 1SMB70AT3 part is unused and in its original packaging.
Return procedure for 1SMB70AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB70AT3 Tags
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