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onsemi 1SMB70AT3G
- Part No.:
- 1SMB70AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB70AT3G.pdf
- Description:
- TVS DIODE 70VWM 113VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:182,860
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Product details
Overview
1SMB70AT3G 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 <1.0 ns response time. It is widely deployed in industrial power supplies and automotive ECUs to suppress ESD and lightning-induced transients.
For engineers reviewing the 1SMB70AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin vs. system operating voltage, peak pulse current capability under 10/1000 µs waveform, UL 497B recognition for isolated loop protection, and SMB package thermal performance in high-density PCB layouts.
Technical Context
The 1SMB70AT3G operates as a unidirectional Zener-based TVS diode, leveraging avalanche breakdown to clamp transient voltages above its VRWM of 70 V. Its low zener impedance and fast intrinsic response (<1.0 ns) enable effective suppression of ESD (Class 3, >16 kV HBM) and surge events per IEC 61000-4-5.
It is rated for 600 W peak pulse power (10/1000 µs waveform), with thermal derating starting at 75°C junction temperature. The device uses ON Semiconductor's SURMETIC™ SMB package (Case 403A), optimized for surface-mount reliability, solderability, and thermal conduction via modified L-bend leads.
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 rail voltage. |
| VBR (min) | 77.8 V @ IT = 1.0 A - Minimum breakdown voltage ensures reliable turn-on above VRWM with margin against tolerance drift. |
| VC @ IPP | 113 V @ 5.3 A - Clamping voltage during 10/1000 µs surge; defines worst-case overvoltage seen by protected ICs. |
| PPK | 600 W @ 1 ms - Peak transient energy handling capacity; validates robustness against IEC 61000-4-5 Level 4 surges. |
| Ctyp | 260 pF @ 0 V, 1 MHz - Junction capacitance impacts high-speed signal integrity; suitable for DC/low-frequency power rails, not USB or HDMI. |
| IR @ VRWM | 5.0 µA max - Low leakage preserves efficiency in battery-backed or high-impedance sensing circuits. |
| Response Time | <1.0 ns - Enables suppression of fast-rising ESD events before downstream components experience overstress. |
Pinout & Package
Package: SMB (Case 403A), surface-mount, Pb-free, void-free thermosetting plastic body with cathode polarity band. Dimensions: 4.32 mm × 3.56 mm × 2.20 mm (L × W × H); thermal resistance RJA = 226 °C/W (FR-4, minimum footprint).
| 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 line connection | Connected to the line being protected (e.g., +12 V rail); polarity band identifies this terminal on PCB silkscreen. |
Key Features
| Feature | Design Value |
|---|---|
| UL 497B Recognition (QVGQ2) | Validated for isolated loop circuit protection in telecom and industrial interfaces-enables compliance without additional certification effort. |
| AEC-Q101 Qualified (SZ variant) | Qualified for automotive applications including engine control modules and body electronics; supports PPAP documentation requirements. |
| ESD Robustness | Class 3 (>16 kV HBM) ensures immunity to human-body model discharges common in assembly and field service environments. |
| SURMETIC™ Package | Enhanced thermal dissipation and mechanical reliability vs. standard SMB; enables stable operation at 150°C junction temperature. |
| Low Clamping Ratio | VC/VRWM = 113/70 ≈ 1.61 - Tight ratio minimizes overvoltage stress on downstream ICs while maintaining safe margin above VBR. |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Protecting 24 V DC input stage of programmable logic controller (PLC) power supply against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VIN and GND, clamping transients before they reach primary-side controller ICs. Use Value: Limits voltage to ≤113 V during 5.3 A surge, preventing latch-up or gate oxide damage in MOSFET drivers and PWM controllers. |
Use Scenario: Safeguarding LIN bus transceiver inputs in door module against ESD and battery reversal spikes. IC Role / Device Role / Timing Role: Standoff protection device on LIN signal line (VBAT-referenced), absorbing fast transients before reaching transceiver ESD structures. Use Value: Sub-1 ns response prevents data corruption during 15 kV contact discharge; UL 497B recognition supports functional safety validation. |
| Medical Equipment Input Stage | Telecom DC Feeder Protection |
|
Use Scenario: Shielding auxiliary 5 V/12 V rails in patient monitor power distribution board from conducted surges on AC mains input. IC Role / Device Role / Timing Role: Secondary-stage TVS after primary MOV/fuse, providing precise clamping where low leakage (<5 µA) is critical for low-power standby circuits. Use Value: 70 V VRWM aligns with 48 V SELV-derived rails; 260 pF capacitance avoids signal distortion on analog sensor bias lines. |
Use Scenario: Protecting -48 V DC feeder lines in remote radio head (RRH) base station against lightning-induced surges on outdoor cabling. IC Role / Device Role / Timing Role: Primary overvoltage clamp on power feed line entering enclosure, coordinated with upstream gas discharge tube (GDT). Use Value: 600 W peak power handles multi-kA induced surges; UL 497B qualification confirms suitability for telecom isolation barrier compliance. |
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 lower PPK = 400 W; SMA package (smaller footprint, higher RJA = 290 °C/W). | Preferred for space-constrained consumer designs where 400 W surge rating suffices; less suitable for industrial 600 W requirement. | Select SMAJ70A only if board area is critical and surge test profile does not exceed 400 W. |
| SMCJ70A | Higher PPK = 1500 W; same VRWM/VC; larger SMC package (7.11 mm × 6.22 mm) with lower RJA = 170 °C/W. | Used in high-reliability infrastructure equipment requiring margin beyond IEC 61000-4-5 Level 4; requires PCB layout revision. | Choose SMCJ70A when long-term surge endurance or extended thermal margin is required, accepting larger footprint. |
Compared with SMAJ70A, the 1SMB70AT3G delivers 50% higher surge power in the same SMB footprint; versus SMCJ70A, it trades 2.3× smaller area for 60% lower peak power-making it optimal for cost-sensitive industrial 600 W applications where space and thermal design are balanced.
Availability
1SMB70AT3G is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, medical auxiliary rails, and telecom DC feeders requiring stable component supply, RoHS-compliant packaging, and UL-recognized surge protection.
Supply support for 1SMB70AT3G 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, sensing, and connectivity solutions for automotive, industrial, and cloud power applications.
The 1SMB70AT3G belongs to the SMB-series unidirectional TVS family, engineered for high-surge, low-leakage protection of DC power rails and signal lines in harsh electromagnetic environments.
FAQ
What is the maximum clamping voltage of the 1SMB70AT3G under standard surge conditions?
The 1SMB70AT3G exhibits a maximum clamping voltage (VC) of 113 V when subjected to its rated peak pulse current (IPP) of 5.3 A under the standard 10/1000 µs waveform. This value is measured per the test conditions defined in the ON Semiconductor datasheet and represents the upper bound of voltage imposed on the protected circuit during a worst-case transient event. Designers must ensure downstream components have sufficient voltage margin above this 113 V clamping level.
Is the 1SMB70AT3G suitable for bidirectional signal line protection?
No, the 1SMB70AT3G is a unidirectional TVS diode and is not suitable for bidirectional signal line protection such as RS-485 or CAN buses. Its electrical behavior is asymmetric: it conducts only when the cathode is biased positively relative to the anode beyond VRWM. For bidirectional applications, ON Semiconductor offers the complementary 1SMB70CAT3G ('C' suffix) variant, which provides symmetrical clamping for AC-coupled or differential signals.
Does the 1SMB70AT3G meet automotive qualification standards?
The base 1SMB70AT3G is not AEC-Q101 qualified; however, the SZ1SMB70AT3G variant-identical in electrical and mechanical specifications-is fully AEC-Q101 qualified and PPAP capable. The 'SZ' prefix denotes automotive-grade traceability, process control, and extended temperature validation (−65°C to +150°C). For automotive BCM or ADAS applications, SZ1SMB70AT3G must be specified.
What is the junction capacitance of the 1SMB70AT3G and how does it affect circuit design?
The 1SMB70AT3G has a typical junction capacitance (Ctyp) of 260 pF at 0 V bias and 1 MHz. This capacitance appears in parallel with the protected line and may attenuate high-frequency signals or cause timing skew in fast digital interfaces. It is appropriate for DC power rails, low-speed analog sensors, and LIN bus protection-but unsuitable for USB 2.0, HDMI, or RF front-end circuits where sub-10 pF loading is required.
How does the UL 497B recognition benefit system-level certification of equipment using the 1SMB70AT3G?
The 1SMB70AT3G holds UL 497B recognition (File #E210057, Category QVGQ2) specifically for isolated loop circuit protection. This pre-certification eliminates the need to retest the entire system for surge withstand in telecom, industrial I/O, and medical isolation barriers. Engineers can reference the UL file number in their technical files to streamline IEC 62368-1 or IEC 60601-1 compliance submissions without additional component-level validation.
1SMB70AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 70V
- Voltage - Breakdown (Min):
- 77.8V
- Voltage - Clamping (Max) @ Ipp:
- 113V
- Current - Peak Pulse (10/1000µs):
- 5.3A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 260pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB70AT3G FAQ
1.How can I place an order for 1SMB70AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB70AT3G 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 1SMB70AT3G reliable?
The price and inventory of 1SMB70AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB70AT3G is usually 5 days.
3.What payment methods are accepted for 1SMB70AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB70AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB70AT3G?
1SMB70AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB70AT3G 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 1SMB70AT3G?
For technical support, including 1SMB70AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB70AT3G requirements.
6.How does Aetrix verify that 1SMB70AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMB70AT3G 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 1SMB70AT3G meets industry standards.
7.What is the process for return or replacement of 1SMB70AT3G?
All 1SMB70AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB70AT3G, 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 1SMB70AT3G part is unused and in its original packaging.
Return procedure for 1SMB70AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB70AT3G Tags
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onsemi
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DESD3V3E1BL-7B
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