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onsemi 1SMA33AT3G
- Part No.:
- 1SMA33AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA33AT3G.pdf
- Description:
- TVS DIODE 33VWM 53.3VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:17,887
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Product details
Overview
1SMA33AT3G from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed for clamping overvoltage transients in DC power rails and signal lines. It features a 33 V working peak reverse voltage (VRWM), 53.3 V clamping voltage at 7.5 A peak pulse current, and <1 ns response time. It is used in automotive power supply protection and industrial control I/O interfaces.
For engineers reviewing the 1SMA33AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin vs. operating voltage, clamping voltage headroom, surge current capability, junction capacitance (375 pF), and AEC−Q101 qualification status.
Technical Context
This device operates as a unidirectional Zener-based TVS diode, conducting only during reverse overvoltage events above its breakdown threshold. Its low zener impedance and fast response ensure effective suppression of ESD and lightning-induced transients without affecting normal circuit operation.
It is rated for 400 W peak pulse power (10/1000 µs waveform), supports 40 A forward surge current, and maintains stable clamping performance across −65 °C to +150 °C operating temperature range. The SMA package enables surface-mount integration with top-slide or bottom-board mounting flexibility.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 33 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR (min/typ/max) | 36.7 / 38.65 / 40.6 V @ 1 mA - Ensures reliable turn-on above system nominal voltage |
| VC @ IPP | 53.3 V @ 7.5 A - Clamping voltage defines worst-case voltage seen by protected IC during surge |
| IPP | 7.5 A - Peak pulse current capacity under standard 10/1000 µs transient waveform |
| CJ | 375 pF @ 0 V, 1 MHz - Limits high-frequency signal integrity impact on data lines |
| ESD Rating | Class 3 (>16 kV HBM) - Meets IEC 61000-4-2 Level 4 for system-level ESD robustness |
| Package | SMA (Case 403D) - Standardized SMD outline with cathode band marking and 2.6 mm × 4.3 mm footprint |
Pinout & Package
The 1SMA33AT3G uses an SMA (DO-214AC) surface-mount package with two terminals: Cathode (marked by molded polarity band) and Anode. The flat handling surface supports accurate automated placement, and the low-profile design allows board-side or top-side mounting.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Transient conduction path during overvoltage | Connected to protected line; conducts when reverse voltage exceeds VBR, shunting surge to ground |
| Anode | Reference/return node | Typically tied to system ground or lower-potential rail; completes clamping current path |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power rating | Withstands high-energy transients such as ISO 7637-2 pulse 5a (load dump) in automotive 12 V systems |
| 33 V VRWM with 53.3 V clamping | Provides ≥10 V margin above 24 V nominal rail while limiting downstream IC stress to safe levels |
| AEC−Q101 qualified | Validated for automotive under-hood and body electronics applications requiring reliability certification |
| 375 pF junction capacitance | Permits use on moderate-speed digital lines (e.g., CAN, LIN, RS-485) without signal degradation |
| Lead-free SURMETIC® package | RoHS-compliant construction with corrosion-resistant finish and 260 °C solderability |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: Protecting microcontroller power inputs in automotive body control modules exposed to load dump transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamping device placed between VCC and GND near point-of-load. Use Value: Limits transient voltage to ≤53.3 V, preventing latch-up or permanent damage to 3.3 V/5 V logic ICs powered from regulated 12 V–24 V supplies. | Use Scenario: Shielding 24 V digital input channels in programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Reverse-biased transient suppressor connected across input optocoupler terminals. Use Value: Absorbs 400 W surges per IEC 61000-4-5 (Level 3), ensuring immunity to 1 kV/2 Ω ring wave transients without false triggering. |
| MEDICAL EQUIPMENT POWER SUPPLY INPUT | TELECOM POWER INTERFACE PROTECTION |
Use Scenario: Safeguarding AC/DC adapter outputs feeding isolated DC-DC converters in diagnostic imaging subsystems. IC Role / Device Role / Timing Role: Primary-stage TVS on secondary-side 12 V/24 V output rail. Use Value: Maintains compliance with IEC 60601-1 creepage/clearance requirements while suppressing fast transients from relay switching or motor commutation. | Use Scenario: Protecting PoE-powered Ethernet switch ports against induced surges from nearby lightning strikes. IC Role / Device Role / Timing Role: Line-to-ground TVS on DC bias feed of 48 V PSE interface. Use Value: Clamps common-mode surges to <55 V, preserving IEEE 802.3af/at compliance and avoiding PSE shutdown due to overvoltage detection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMA33AT3G | Identical electrical specs; AEC−Q101 certified with PPAP documentation support | Required for automotive OEM production programs needing full traceability and change control | Select when automotive qualification and process validation are mandatory |
| 1.5SMC33A | Same VRWM and VC, but larger SMC package (7.1 mm × 6.2 mm); 1500 W peak power rating | Better suited for higher-energy transients where PCB space permits larger footprint | Choose for industrial applications demanding >400 W surge margin and thermal mass |
Compared with 1SMA33AT3G, SZ1SMA33AT3G adds automotive-grade process controls and documentation, while 1.5SMC33A trades compact size for higher surge capacity-enabling design flexibility based on space constraints and energy threat level.
Availability
1SMA33AT3G is available at Aetrix Electronics and suitable for automotive power rail protection, industrial PLC I/O protection, and medical equipment power supply input applications requiring stable component supply and long-term sourcing continuity.
Supply support for 1SMA33AT3G 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 communications markets.
The 1SMAxxAT3G series belongs to ON Semiconductor's SURMETIC® TVS portfolio, engineered specifically for cost-sensitive, high-reliability overvoltage protection in harsh environments including automotive under-hood and factory automation systems.
FAQ
What is the maximum clamping voltage of the 1SMA33AT3G under standard test conditions?
The 1SMA33AT3G has a maximum clamping voltage (VC) of 53.3 V when subjected to its rated peak pulse current (IPP) of 7.5 A using the 10/1000 µs waveform. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during a transient event. The 1SMA33AT3G maintains this clamping performance across its specified operating temperature range.
Is the 1SMA33AT3G suitable for automotive applications?
Yes, the 1SMA33AT3G meets industrial reliability standards and is functionally identical to the AEC−Q101-qualified SZ1SMA33AT3G variant. While the base 1SMA33AT3G part number itself is not AEC−Q101 certified, its construction, materials, and electrical characteristics align with automotive-grade requirements. For production automotive use, the SZ1SMA33AT3G should be selected to ensure full qualification compliance.
What is the junction capacitance of the 1SMA33AT3G and how does it affect circuit performance?
The 1SMA33AT3G exhibits a typical junction capacitance (CJ) of 375 pF at 0 V bias and 1 MHz. This value impacts high-frequency signal integrity: on data lines like CAN or RS-485, it introduces minimal loading below ~10 Mbps but may attenuate edges in >50 Mbps interfaces. The 1SMA33AT3G remains appropriate for most industrial serial buses where bandwidth demands are moderate and transient protection takes priority over ultra-low capacitance.
How does the 1SMA33AT3G compare to bidirectional TVS diodes in terms of application scope?
The 1SMA33AT3G is unidirectional and intended for DC-biased lines where polarity is fixed-such as power rails or single-ended signal paths referenced to ground. Unlike bidirectional TVS diodes, it does not protect against positive-going transients on grounded lines. For AC-coupled or floating signals (e.g., telecom lines), a bidirectional device like 1SMA33CAT3G would be required. The 1SMA33AT3G offers tighter clamping and lower leakage than equivalent bidirectional parts in its intended use cases.
What is the thermal resistance and derating behavior of the 1SMA33AT3G in real-world PCB layouts?
The 1SMA33AT3G has a junction-to-ambient thermal resistance (RJA) of 250 °C/W on a standard FR-4 board with minimum recommended footprint, and junction-to-lead resistance (RJL) of 50 °C/W. Its DC power dissipation derates linearly above 25°C ambient (4.0 mW/°C) and above 75°C lead temperature (20 mW/°C). In practice, sustained power dissipation must remain below 0.5 W at 25°C ambient; the 1SMA33AT3G is optimized for transient-not continuous-power handling.
1SMA33AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 7.5A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 375pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA33AT3G FAQ
1.How can I place an order for 1SMA33AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA33AT3G 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 1SMA33AT3G reliable?
The price and inventory of 1SMA33AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA33AT3G is usually 5 days.
3.What payment methods are accepted for 1SMA33AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA33AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA33AT3G?
1SMA33AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA33AT3G 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 1SMA33AT3G?
For technical support, including 1SMA33AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA33AT3G requirements.
6.How does Aetrix verify that 1SMA33AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMA33AT3G 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 1SMA33AT3G meets industry standards.
7.What is the process for return or replacement of 1SMA33AT3G?
All 1SMA33AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA33AT3G, 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 1SMA33AT3G part is unused and in its original packaging.
Return procedure for 1SMA33AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA33AT3G Tags
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