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onsemi 1SMC12AT3
- Part No.:
- 1SMC12AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- -
- Datasheet:
-
1SMC12AT3.pdf
- Description:
- TVS DIODE 12V 19.9V SMC
- Quantity:
- Payment:
- Shipping:
Inventory:2,028
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Product details
Overview
1SMC12AT3 from ON Semiconductor is a unidirectional 1500 W peak power Zener transient voltage suppressor (TVS) designed for parallel clamping protection of DC power rails and signal lines. It features a 12 V working peak reverse voltage (VRWM), 14.7 V nominal breakdown voltage (VBR) at 1 A test current, and clamps to ≤19.9 V at 75.3 A peak pulse current - making it suitable for automotive power line surge suppression per ISO 7637-2 and industrial IEC 61000-4-5 Level 4.
For engineers reviewing the 1SMC12AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC VDD, peak pulse current handling under 8.3 ms surge waveforms, UL 497B certification for isolated loop circuits, and SMC package thermal performance in high-reliability PCB layouts.
Technical Context
The 1SMC12AT3 operates as a silicon avalanche diode with Zener-based breakdown mechanism, delivering sub-1 ns response time and low dynamic impedance (<0.5 Ω typical) during transient events. Its unidirectional polarity enables asymmetric clamping - conducting only during negative transients on the anode side - and requires cathode-to-rail connection for positive-line protection.
Thermal design relies on junction-to-lead resistance of 54.6 °C/W and 4.0 W DC power dissipation at 75 °C lead temperature. The device is rated for −65 °C to +150 °C operating range and supports 200 A non-repetitive forward surge current, enabling robustness against repetitive load dump pulses in 12 V automotive systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 12 V - maximum continuous reverse voltage before clamping begins; sets minimum system operating voltage margin |
| VBR @ IT=1 A | 14.7 V (nominal) - precise avalanche onset point used for tolerance-based circuit margining |
| VC @ IPP=75.3 A | ≤19.9 V - clamped voltage during 8.3 ms surge; determines maximum stress on downstream ICs |
| PPK | 1500 W @ 1 ms - peak surge energy handling capacity aligned with IEC 61000-4-5 waveform requirements |
| IR @ VRWM | ≤5 μA - ultra-low leakage ensures minimal standby power loss in battery-backed systems |
| Response Time | <1 ns - enables effective suppression of fast ESD and lightning-induced edge transients |
| UL 497B | Certified - validated for isolated loop circuit protection including strike voltage, endurance, and dielectric withstand tests |
Pinout & Package
1SMC12AT3 is housed in the SMC (Case 403) surface-mount plastic package: void-free thermosetting body, modified L-bend leads, cathode indicated by molded notch, and RoHS-compliant Pb-free construction. Dimensions: 5.84 mm × 6.86 mm × 2.13 mm (L × W × H).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current sink path | Connected to protected line (e.g., 12 V rail); conducts during overvoltage events toward ground |
| Cathode | Reference/return node | Connected to system ground or low-impedance return plane; defines clamping reference potential |
Key Features
| Feature | Design Value |
|---|---|
| 1500 W peak pulse power | Supports IEC 61000-4-5 Level 4 (4 kV/2 Ω) surge testing without derating in standard PCB footprints |
| Clamp voltage ≤19.9 V @ 75.3 A | Provides ≥2.1 V margin below typical 22 V absolute maximum rating of automotive microcontrollers |
| ESD rating >16 kV HBM | Eliminates need for secondary ESD protection on board-level interfaces exposed to handling environments |
| UL 497B recognition | Validated for telecom and industrial isolated loop applications - includes full strike voltage and endurance compliance |
| −65 °C to +150 °C operation | Enables deployment in engine bay, powertrain, and industrial control enclosures without thermal derating |
Applications
| Automotive Power Line Protection | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Suppresses load dump transients (up to 60 V, 400 ms) on 12 V vehicle battery-fed ECUs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and ground, clamping within 1 ns to protect CAN transceivers and MCU power inputs. Use Value: Maintains <19.9 V clamp level across full temperature range, preventing latch-up or permanent damage to 3.3 V/5 V logic supplies. |
Use Scenario: Shields 24 V digital input modules from field-wiring induced surges in factory automation cabinets. IC Role / Device Role / Timing Role: Parallel-connected TVS on each channel input, referenced to common ground, activated by fast-rising transients from relay coil flyback or motor switching. Use Value: Withstands 1500 W surges without degradation, ensuring >100,000 surge cycles per channel per IEC 61000-4-4 compliance. |
| Medical Equipment Power Rails | Telecom Isolated Loop Interfaces |
Use Scenario: Protects auxiliary 12 V DC-DC converter outputs powering analog sensor front-ends in diagnostic imaging systems. IC Role / Device Role / Timing Role: Low-leakage (≤5 μA) TVS placed post-filtering to avoid compromising signal integrity while blocking EFT bursts. Use Value: Sub-μA leakage preserves battery life in portable ultrasound units; UL 497B certification satisfies medical isolation barrier requirements. |
Use Scenario: Clamps induced surges on RS-485 or current-loop (4–20 mA) interfaces connected to outdoor sensors in smart grid infrastructure. IC Role / Device Role / Timing Role: UL 497B-recognized TVS installed on isolated side of signal transformer, referenced to local ground to prevent insulation breakdown. Use Value: Certified performance under dielectric withstand and discharge tests ensures long-term reliability in harsh outdoor environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMC12AT3G | Automotive-grade variant with AEC-Q101 qualification, identical electrical specs and SMC package | Required for production automotive ECUs; supports PPAP documentation and extended temperature screening | Select 1SMC12AT3 for industrial/commercial use; choose SZ1SMC12AT3G when automotive qualification is mandatory |
| SMBJ12A | Lower peak power (600 W), same VRWM (12 V), SMB package (smaller footprint, higher thermal resistance) | Suitable for space-constrained consumer electronics with lower surge threat levels (IEC 61000-4-5 Level 2) | Use SMBJ12A where board area is critical and surge energy does not exceed 600 W; retain 1SMC12AT3 for full 1500 W immunity |
Compared with SZ1SMC12AT3G and SMBJ12A, the 1SMC12AT3 offers the optimal balance of industrial-grade surge robustness, UL 497B certification, and cost-effective SMC packaging - making it ideal for non-automotive applications requiring full 1500 W IEC 61000-4-5 compliance without AEC-Q101 overhead.
Availability
1SMC12AT3 is available at Aetrix Electronics and suitable for automotive power line protection, industrial PLC I/O protection, and medical equipment power rails requiring stable component supply and full IEC/UL compliance.
Supply support for 1SMC12AT3 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 discrete devices for automotive, industrial, and cloud power applications.
The 1SMC12AT3 belongs to the SMC-series Zener TVS family, engineered for high-energy transient suppression in harsh environments - emphasizing clamping precision, surge repeatability, and regulatory certification for mission-critical systems.
FAQ
What is the clamping voltage of the 1SMC12AT3 under maximum surge conditions?
The 1SMC12AT3 clamps to a maximum of 19.9 V when subjected to its rated peak pulse current of 75.3 A (8.3 ms waveform). This value is measured per Figure 2 in the ON Semiconductor datasheet and represents the upper limit of voltage seen by protected circuitry during worst-case transients - critical for verifying margin against downstream IC absolute maximum ratings.
Is the 1SMC12AT3 RoHS-compliant and halogen-free?
Yes, the 1SMC12AT3 is manufactured in ON Semiconductor's Pb-free SURMETIC™ package and complies with RoHS Directive 2011/65/EU. While the datasheet confirms Pb-free status, halogen content is not explicitly specified; however, ON Semiconductor's standard SMC packaging meets JEDEC JS709C requirements for low-halogen materials unless otherwise noted in part-specific documentation.
Can the 1SMC12AT3 be used in bidirectional configurations?
No - the 1SMC12AT3 is strictly unidirectional, as confirmed in the datasheet footnote stating "Bidirectional devices will not be available in this series." For bidirectional protection, engineers must select alternate families such as the P6SMB series or explicitly marked bidirectional variants like 1.5KE12CA; using two 1SMC12AT3 devices in series opposition is not recommended due to mismatched VBR tolerances and undefined clamping symmetry.
What is the thermal resistance from junction to ambient for the 1SMC12AT3?
The 1SMC12AT3 has a junction-to-ambient thermal resistance (RJA) of 165 °C/W when mounted on an FR-4 board using ON Semiconductor's minimum recommended footprint. This value assumes no copper pour or thermal vias; actual RJA improves significantly with added copper area - e.g., 2 in² pad reduces RJA to ~50 °C/W, directly impacting safe operating area during repetitive surge events.
Does the 1SMC12AT3 require a series current-limiting resistor in typical applications?
No - the 1SMC12AT3 is designed for direct parallel connection across protected lines and does not require a series resistor. Its low dynamic impedance and fast response enable self-limiting behavior during transients. However, a small series impedance (e.g., ferrite bead or trace inductance) may be intentionally retained to reduce di/dt-induced overshoot, as noted in the datasheet's Application Notes section on inductive effects.
1SMC12AT3 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:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
1SMC12AT3 FAQ
1.How can I place an order for 1SMC12AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMC12AT3 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 1SMC12AT3 reliable?
The price and inventory of 1SMC12AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMC12AT3 is usually 5 days.
3.What payment methods are accepted for 1SMC12AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMC12AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMC12AT3?
1SMC12AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMC12AT3 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 1SMC12AT3?
For technical support, including 1SMC12AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMC12AT3 requirements.
6.How does Aetrix verify that 1SMC12AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMC12AT3 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 1SMC12AT3 meets industry standards.
7.What is the process for return or replacement of 1SMC12AT3?
All 1SMC12AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMC12AT3, 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 1SMC12AT3 part is unused and in its original packaging.
Return procedure for 1SMC12AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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