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onsemi 1SMC70AT3
- Part No.:
- 1SMC70AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMC70AT3.pdf
- Description:
- TVS 1500W 70V UNIDIRECT SMC
- Quantity:
- Payment:
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Inventory:9,109
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Product details
Overview
1SMC70AT3 from ON Semiconductor is a unidirectional 1500 W transient voltage suppressor (TVS) diode designed for parallel clamping protection of sensitive electronics against ESD, lightning-induced surges, and inductive switching transients. It features a 70 V working peak reverse voltage (VRWM), 86 V typical breakdown voltage (VBR) at 1 A test current, 113 V maximum clamping voltage (VC) at 13.3 A peak pulse current, and sub-1 ns response time. It is widely deployed in industrial power supplies and automotive ECUs where robust overvoltage immunity is required.
For engineers reviewing the 1SMC70AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to system operating voltage, peak pulse current handling under IEC 61000-4-5 surge waveforms, UL 497B certification for isolated loop protection, and SMC package thermal performance in high-density PCB layouts.
Technical Context
The 1SMC70AT3 operates as a unidirectional Zener-based TVS diode with avalanche breakdown behavior, optimized for fast transient suppression without forward conduction during normal operation. Its junction design delivers low dynamic impedance (<1 Ω typical at IPP) and stable temperature coefficient across −65°C to +150°C operating range.
It complies with UL 497B for isolated loop circuit protection and meets Class 3 ESD immunity (>16 kV HBM). The device is rated for non-repetitive 1 ms pulses up to 1500 W and supports forward surge current up to 200 A (8.3 ms half-sine), making it suitable for primary-side surge protection in AC/DC front-ends and DC bus lines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 70 V - Maximum continuous reverse operating voltage before clamping begins; sets minimum system voltage margin for reliable standby operation. |
| VBR @ IT=1 A | 77.8 V (min) to 91.25 V (max) - Breakdown onset range; defines threshold where avalanche conduction initiates under controlled test conditions. |
| VC @ IPP=13.3 A | 113 V - Maximum clamped voltage during 1 ms 13.3 A surge; determines worst-case overvoltage stress on downstream components. |
| PPK | 1500 W - Peak pulse power rating at TL=25°C; defines single-event energy absorption capability per IEC 61000-4-5 waveform. |
| IR @ VRWM | 5 µA max - Reverse leakage at rated working voltage; ensures negligible standby power loss and signal integrity in high-impedance circuits. |
| Response Time | <1 ns - Time from transient onset to clamping initiation; critical for protecting nanosecond-scale logic and analog interfaces. |
| Thermal Resistance RJA | 165 °C/W - Junction-to-ambient thermal resistance on FR-4 board; informs derating requirements above 25°C ambient. |
Pinout & Package
1SMC70AT3 is housed in an SMC (DO-214AB) surface-mount plastic package (Case 403), featuring a modified L-bend lead form for enhanced solder joint reliability and cathode polarity indicated by a molded notch. The package measures 5.59–6.10 mm × 6.60–7.11 mm × 1.90–2.41 mm (L×W×H) and is Pb-free compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction or surge clamping | Connected to ground or low-impedance return path in unidirectional protection configuration. |
| Cathode | Current exit terminal during clamping; marked by molded notch | Connected to protected line (e.g., DC input rail); defines polarity-sensitive placement on PCB. |
Key Features
| Feature | Design Value |
|---|---|
| UL 497B Recognition | Qualified for protector category under UL 497B (File #E210057), enabling use in certified isolated loop telecom and industrial control systems. |
| 1500 W Peak Pulse Power | Withstands single-event surges up to 1500 W at 1 ms pulse width, meeting Level 4 IEC 61000-4-5 (4 kV/2 Ω) requirements without external series impedance. |
| ESD Robustness | Class 3 HBM rating (>16 kV) ensures immunity to human-body model discharges common in manufacturing and field service environments. |
| Low Clamping Ratio | VC/VRWM ≈ 1.61 (113 V / 70 V) - tight ratio minimizes overvoltage overshoot while maintaining sufficient margin above operating voltage. |
| Thermal Performance | RJL = 54.6 °C/W (junction-to-lead) enables effective heat transfer to copper pour, supporting sustained surge duty in thermally constrained designs. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Protects AC/DC converter input stage against line surges, load dump transients, and ESD events in factory automation power supplies. IC Role / Device Role / Timing Role: Unidirectional clamping diode placed between rectified DC bus and chassis ground, activated only during overvoltage events. Use Value: Limits transient voltage to ≤113 V, preventing damage to bridge rectifiers, bulk capacitors, and primary-side controllers such as UC384x or VIPer series ICs. |
Use Scenario: Shields LIN bus interface and microcontroller I/O pins from battery voltage spikes and alternator load dump in vehicle body electronics. IC Role / Device Role / Timing Role: Standby protection element connected between LIN line and ground, responding within <1 ns to suppress >100 V transients. Use Value: Maintains signal integrity below ISO 16750-2 Level IV thresholds (100 V/100 ms) while adding <0.5 pF capacitance-negligible for 20 kbps LIN signaling. |
| Medical Equipment DC Rail Protection | Programmable Logic Controller (PLC) Digital I/O |
|
Use Scenario: Safeguards 24 V DC auxiliary rails in diagnostic imaging equipment against coupling from MRI gradient coil switching noise. IC Role / Device Role / Timing Role: Primary overvoltage clamp on regulated 24 V supply feeding FPGA configuration circuitry and sensor bias networks. Use Value: Clamps 13.3 A surges to 113 V, ensuring downstream LDOs (e.g., TPS7A47) remain within absolute maximum ratings and avoid latch-up. |
Use Scenario: Protects 24 V digital input channels in industrial PLC backplanes from field-wiring induced transients and relay contact bounce. IC Role / Device Role / Timing Role: Discrete TVS mounted directly at terminal block entry point, shunting surge energy before optocoupler input stage. Use Value: Absorbs 1500 W surges without degradation, preserving optocoupler CTR stability and eliminating false triggering in safety-critical discrete I/O modules. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ70A | Same VRWM (70 V) and VC (113 V), but lower PPK = 600 W; SMB package has higher RJA (210 °C/W) and smaller footprint. | Limited to lower-energy transients (IEC 61000-4-5 Level 2); unsuitable for 4 kV/2 Ω surge testing without series impedance. | Select SMBJ70A only when board space is constrained and surge threat level is ≤1 kV line-to-ground. |
| 1.5SMC70A | Identical electrical specs and SMC package, but obsolete marking (no 'G' suffix); RoHS-compliant version is 1.5SMC70AT3G. | No functional difference; legacy part may lack current UL 497B documentation or Pb-free traceability. | Prefer 1SMC70AT3 for new designs requiring full compliance documentation and guaranteed Pb-free sourcing. |
Compared with SMBJ70A and 1.5SMC70A, the 1SMC70AT3 provides superior surge energy handling (1500 W vs. 600 W or legacy 1500 W without updated certification), verified UL 497B recognition, and guaranteed Pb-free construction-making it the preferred choice for industrial and automotive applications demanding full regulatory alignment and long-term supply continuity.
Availability
1SMC70AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive electronic control units, and medical diagnostic equipment requiring stable component supply and certified surge protection performance.
Supply support for 1SMC70AT3 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, and cloud power applications.
The 1SMC70AT3 belongs to the SMC-series Zener TVS family, engineered specifically for high-energy transient suppression in harsh electromagnetic environments-targeting reliability-critical infrastructure where failure is not an option.
FAQ
What is the maximum clamping voltage of the 1SMC70AT3 under standard surge conditions?
The 1SMC70AT3 exhibits a maximum clamping voltage (VC) of 113 V when subjected to its rated peak pulse current of 13.3 A with a 1 ms pulse width. This value is measured per the standard 10/1000 µs surge waveform and represents the worst-case voltage seen by protected circuitry during transient events. Designers must ensure this clamping level remains safely below the absolute maximum ratings of downstream components.
Does the 1SMC70AT3 meet UL 497B certification, and what does that mean for system design?
Yes, the 1SMC70AT3 carries UL 497B recognition (File #E210057) in the Protector category, confirming successful validation across strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge tests. This certification allows direct use in UL-listed isolated loop systems-such as telecom interfaces and industrial fieldbus nodes-without requiring additional system-level surge testing or external protective components.
Can the 1SMC70AT3 be used in bidirectional protection configurations?
No, the 1SMC70AT3 is explicitly a unidirectional TVS diode, as confirmed by ON Semiconductor's datasheet and marking diagram. Bidirectional variants are not offered in the SMC5.0AT3 series. For AC-line or differential-signal protection requiring symmetrical clamping, designers must select dedicated bidirectional parts such as SMBJ70CA or SMAJ70CA-never substitute unidirectional devices in reverse-biased AC applications.
What is the thermal resistance and derating behavior of the 1SMC70AT3 at elevated ambient temperatures?
The 1SMC70AT3 has a junction-to-ambient thermal resistance (RJA) of 165 °C/W on standard FR-4 board. Its DC power dissipation derates linearly above 25°C ambient at 6.1 mW/°C, dropping to 0.75 W at 25°C and zero at approximately 140°C. For pulsed operation, Figure 3 in the datasheet shows 50% peak power derating at 100°C ambient-critical for high-temperature enclosures like engine bay electronics.
How does the 1SMC70AT3 compare to older 1.5SMC70A parts in terms of compliance and reliability?
The 1SMC70AT3 supersedes legacy 1.5SMC70A with verified Pb-free construction ('G' suffix), updated UL 497B documentation, and tighter process controls reflected in improved parameter consistency. While electrical specs align, the 1SMC70AT3 guarantees RoHS compliance, full traceability, and ongoing production support-whereas 1.5SMC70A is obsolete and lacks current certification records or supply chain assurance.
1SMC70AT3 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:
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- 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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1SMC70AT3 FAQ
1.How can I place an order for 1SMC70AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMC70AT3 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 1SMC70AT3 reliable?
The price and inventory of 1SMC70AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMC70AT3 is usually 5 days.
3.What payment methods are accepted for 1SMC70AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMC70AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMC70AT3?
1SMC70AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMC70AT3 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 1SMC70AT3?
For technical support, including 1SMC70AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMC70AT3 requirements.
6.How does Aetrix verify that 1SMC70AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMC70AT3 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 1SMC70AT3 meets industry standards.
7.What is the process for return or replacement of 1SMC70AT3?
All 1SMC70AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMC70AT3, 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 1SMC70AT3 part is unused and in its original packaging.
Return procedure for 1SMC70AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMC70AT3 Tags
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