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onsemi 1SMB12AT3G
- Part No.:
- 1SMB12AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB12AT3G.pdf
- Description:
- TVS DIODE 12VWM 19.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:52,250
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Product details
Overview
1SMB12AT3G 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 12 V working peak reverse voltage (VRWM), 14.7 V minimum breakdown voltage (VBR) at 1.0 mA test current, and clamps transients to ≤19.9 V at 30.2 A peak pulse current (IPP), making it suitable for DC power rail protection in industrial power supplies and automotive control modules.
For engineers reviewing the 1SMB12AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system operating voltage, clamping voltage margin relative to IC absolute maximum ratings, surge current capability under 10/1000 µs waveform, and UL 497B recognition for isolated loop circuit protection.
Technical Context
The 1SMB12AT3G operates as a Zener-based avalanche diode, entering conduction when reverse voltage exceeds its specified VBR range (13.3–14.7 V). Its low zener impedance and sub-1 ns response time enable rapid clamping of ESD and lightning-induced transients without thermal runaway under single-pulse conditions.
It is rated for 600 W peak pulse power (10/1000 µs waveform), with thermal resistance from junction-to-lead of 25 °C/W and junction-to-ambient of 226 °C/W. The device supports forward surge current up to 100 A (8.3 ms half-sine) and exhibits <5.0 µA leakage at VRWM.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 12 V - Maximum continuous reverse operating voltage before clamping begins; must exceed system DC bus voltage. |
| VBR (min/max) | 13.3 V / 14.7 V @ IT = 1.0 mA - Ensures reliable turn-on above normal operating voltage while avoiding false triggering. |
| VC @ IPP | 19.9 V @ 30.2 A - Clamped voltage during 10/1000 µs surge; defines maximum stress on downstream components. |
| PPK | 600 W @ 1 ms - Peak transient energy handling capacity; validates robustness against IEC 61000-4-5 Level 4 surges. |
| IR @ VRWM | 5.0 µA max - Low leakage preserves efficiency in high-impedance bias networks and battery-powered circuits. |
| Response Time | <1.0 ns - Enables suppression before fast-rising transients (e.g., ESD) damage CMOS inputs or communication interfaces. |
| UL Recognition | UL 497B (QVGQ2) - Certified for use in isolated loop protection circuits per safety standard for telecom and industrial interfaces. |
Pinout & Package
Package: SMB (Case 403A), surface-mount, Pb-free, void-free thermosetting plastic with modified L-bend leads and cathode polarity band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current path / Transient return path | Connected to ground or low-impedance return plane; forms current loop with protected line during clamping. |
| Cathode | Protected line connection / Zener anode terminal | Connected to the line being protected (e.g., +12 V rail); reverse-biased during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power | Supports IEC 61000-4-5 surge immunity up to 4 kV (line-earth) in properly designed PCB layouts. |
| ESD rating >16 kV HBM | Meets or exceeds IEC 61000-4-2 Level 4 (±15 kV air, ±8 kV contact) without external series impedance. |
| Low clamping ratio (VC/VBR ≈ 1.42) | Minimizes overvoltage margin required between protected IC's absolute max rating and system operating voltage. |
| UL 497B recognition | Validates suitability for safety-critical telecom and industrial isolation barrier protection applications. |
| SURMETIC™ package reliability | Proven moisture resistance and thermal cycling performance in automotive under-hood environments (−65°C to +150°C). |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: Protecting 12 V DC input rails in programmable logic controllers (PLCs) against load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed directly across input terminals to clamp surges before they reach upstream DC-DC converters and microcontrollers. Use Value: Limits transient voltage to ≤19.9 V, ensuring survival of 24 V-rated input stages and preventing latch-up in 3.3 V/5 V logic domains. |
Use Scenario: Safeguarding LIN bus transceivers and sensor supply lines in BCMs exposed to battery voltage spikes during alternator load dump. IC Role / Device Role / Timing Role: Parallel-connected TVS on 12 V sensor supply rail, activated within <1 ns to suppress 100 V/100 ms load dump events. Use Value: Maintains functional integrity of analog sensor front-ends and LIN PHY by holding rail voltage below 20 V during surge. |
| Medical Equipment Input Stage | Telecom Isolated Interface Protection |
Use Scenario: Shielding auxiliary 12 V power inputs in portable ultrasound devices from ESD and coupling noise in hospital environments. IC Role / Device Role / Timing Role: First-line transient suppressor on isolated DC input, preceding EMI filter and DC-DC stage. Use Value: Provides Class 3 (>16 kV HBM) ESD immunity without degrading signal integrity or requiring additional RC filtering. |
Use Scenario: Protecting RS-485 transceiver power pins in UL 497B-compliant isolated data interfaces used in building automation systems. IC Role / Device Role / Timing Role: UL-recognized TVS on isolated 12 V supply side of digital isolator, meeting safety requirements for secondary-side surge protection. Use Value: Enables compliance with UL 497B Strike Voltage Breakdown and Endurance Conditioning tests for protector-class certification. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ12A | Lower peak power (400 W), same VRWM (12 V), higher VC (20.9 V @ 19.7 A), SMA package (smaller footprint, lower thermal mass). | Better suited for space-constrained consumer electronics where 400 W surge margin is sufficient and board area is critical. | Select SMAJ12A only if system-level surge testing confirms 400 W rating meets IEC 61000-4-5 requirements and thermal derating allows full power at ambient temperature. |
| 1.5SMC12A | Higher peak power (1500 W), same VRWM (12 V), lower clamping (19.0 V @ 79.4 A), larger SMC package (7.1 mm × 6.2 mm vs. SMB 4.6 mm × 3.6 mm). | Preferred for high-reliability industrial motor drives where repeated 1 kV surges demand greater energy absorption and thermal margin. | Choose 1.5SMC12A when PCB layout permits larger footprint and system requires >600 W single-pulse handling or multi-pulse endurance beyond SMB thermal limits. |
Compared with SMAJ12A, the 1SMB12AT3G delivers 50% higher surge energy capacity in a compact SMB package but requires more careful thermal management; versus 1.5SMC12A, it trades 2.5× peak power for 40% smaller board area and faster response due to lower parasitic inductance.
Availability
1SMB12AT3G is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and medical equipment requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1SMB12AT3G 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 power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The 1SMB12AT3G belongs to the SMB-series Zener TVS family, engineered for cost-effective, high-reliability transient suppression in harsh environments where UL recognition, AEC-Q101 qualification, and consistent clamping performance are mandatory.
FAQ
What is the maximum clamping voltage of the 1SMB12AT3G under standard surge conditions?
The 1SMB12AT3G clamps to a maximum of 19.9 V at 30.2 A peak pulse current (IPP), measured using the industry-standard 10/1000 µs double-exponential surge waveform. This value is guaranteed across temperature and ensures downstream components rated for 20 V absolute maximum will remain within safe operating limits during transient events. The 1SMB12AT3G achieves this with minimal voltage overshoot due to its sub-1 ns response time and low package inductance.
Is the 1SMB12AT3G suitable for automotive applications?
Yes, the 1SMB12AT3G is AEC-Q101 qualified and PPAP capable, with operating temperature range from −65°C to +150°C and robust construction in ON Semiconductor's SURMETIC™ package. It is widely deployed in automotive body control modules, infotainment power rails, and sensor interfaces where load dump and ISO 7637-2 pulse 5a/b immunity are required. The 1SMB12AT3G also meets UL 497B for isolated loop protection in vehicle communication gateways.
How does the 1SMB12AT3G differ from bidirectional TVS diodes?
The 1SMB12AT3G is unidirectional and functions only during reverse-voltage transients - it behaves like a standard rectifier diode under forward bias. Unlike bidirectional TVS diodes (e.g., 1SMB12CAT3G), it does not suppress positive-going transients on grounded lines. This makes the 1SMB12AT3G ideal for protecting positive DC rails referenced to ground, where forward conduction is acceptable and reverse clamping is the sole requirement. Its unidirectional nature yields lower leakage and tighter VBR tolerance than equivalent bidirectional parts.
What is the thermal resistance and power derating behavior of the 1SMB12AT3G?
The 1SMB12AT3G has a junction-to-lead thermal resistance (RJL) of 25 °C/W and junction-to-ambient (RJA) of 226 °C/W on a FR-4 board with ON Semiconductor's recommended footprint. At ambient temperatures above 25°C, its DC power dissipation derates linearly at 4.4 mW/°C, while peak pulse power remains valid only at TL = 25°C. For sustained surge duty cycles, average power must be limited per Figure 3 in the datasheet to prevent thermal runaway - the 1SMB12AT3G is intended for non-repetitive events unless actively cooled.
Does the 1SMB12AT3G require external series impedance for ESD protection?
No, the 1SMB12AT3G provides intrinsic ESD protection rated at >16 kV per Human Body Model (HBM) without any external series resistor. Its low dynamic impedance and sub-1 ns response allow direct placement across protected lines (e.g., 12 V supply to ground), eliminating the need for added components that could degrade signal rise time or introduce voltage drop. However, for data line protection (e.g., CAN, LIN), a series resistor may still be needed to limit current into transceiver pins - the 1SMB12AT3G itself does not require it for basic power rail clamping.
1SMB12AT3G 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):
- 12V
- Voltage - Breakdown (Min):
- 13.3V
- Voltage - Clamping (Max) @ Ipp:
- 19.9V
- Current - Peak Pulse (10/1000µs):
- 30.2A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 1245pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB12AT3G FAQ
1.How can I place an order for 1SMB12AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB12AT3G 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 1SMB12AT3G reliable?
The price and inventory of 1SMB12AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB12AT3G is usually 5 days.
3.What payment methods are accepted for 1SMB12AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB12AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB12AT3G?
1SMB12AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB12AT3G 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 1SMB12AT3G?
For technical support, including 1SMB12AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB12AT3G requirements.
6.How does Aetrix verify that 1SMB12AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMB12AT3G 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 1SMB12AT3G meets industry standards.
7.What is the process for return or replacement of 1SMB12AT3G?
All 1SMB12AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB12AT3G, 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 1SMB12AT3G part is unused and in its original packaging.
Return procedure for 1SMB12AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB12AT3G Tags
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DESD3V3E1BL-7B
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