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onsemi SZ1SMC51AT3G
- Part No.:
- SZ1SMC51AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SZ1SMC51AT3G.pdf
- Description:
- TRANS VOLTAGE SUPPRESSOR DIODE
- Quantity:
- Payment:
- Shipping:
Inventory:2,488
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Product details
Overview
SZ1SMC51AT3G from onsemi is a unidirectional 1500 W peak power Zener transient voltage suppressor (TVS) diode designed for parallel clamping protection of sensitive electronics against ESD, lightning, and inductive load transients. It features a 51 V working peak reverse voltage (VRWM), 62.7 V breakdown voltage (VBR) at 1 A test current, 82.4 V maximum clamping voltage (VC) at 18.2 A peak pulse current, and <1 ns response time. It is widely deployed in automotive power supply rails and industrial I/O interfaces.
For engineers reviewing the SZ1SMC51AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC VDD, VRWM compatibility with steady-state operating voltage, UL 497B certification for isolated loop systems, and AEC−Q101 qualification for automotive deployment.
Technical Context
The SZ1SMC51AT3G operates as a unidirectional Zener-based TVS diode, conducting only in reverse bias above its breakdown threshold while presenting high impedance below VRWM. Its low dynamic impedance and sub-nanosecond turn-on enable effective suppression of fast-rising transients such as ESD (IEC 61000-4-2 Level 4) and ISO 7637-2 pulses.
It is thermally rated for 75 °C lead temperature operation with 54.6 °C/W junction-to-lead thermal resistance and supports forward surge current up to 200 A (8.3 ms half-sine). The device uses ON Semiconductor's SURMETIC™ SMC package with modified L-bend leads and Pb-free finish, qualified per AEC−Q101 for automotive underhood applications.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 51 V - Maximum continuous reverse operating voltage before clamping begins; must exceed system DC rail voltage. |
| VBR @ IT=1 A | 62.7 V - Measured Zener breakdown voltage; defines onset of avalanche conduction under transient stress. |
| VC @ IPP=18.2 A | 82.4 V - Maximum clamped voltage during 1 ms 1500 W pulse; determines worst-case overvoltage seen by protected circuit. |
| IPP | 18.2 A - Peak pulse current corresponding to 1500 W dissipation; used to size series impedance for current limiting. |
| Response Time | <1 ns - Enables suppression of transients faster than most microcontroller I/O or CAN bus edges. |
| ESD Rating | Class 3 (>16 kV HBM) - Meets stringent electrostatic discharge immunity requirements for automotive and industrial terminals. |
| UL Recognition | UL 497B - Certified for use in isolated loop circuit protection, including telecom and process control signal lines. |
Pinout & Package
Package: SMC (Case 403), surface-mount, Pb-free, void-free thermosetting plastic with cathode polarity notch and modified L-bend leads. Dimensions: 5.59–6.10 mm (D) × 6.60–7.11 mm (E) × 1.90–2.41 mm (A), 0.76–1.27 mm lead length (L).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current sink during clamping | Connected to ground or low-impedance return path; carries full transient current during suppression event. |
| Cathode | High-side connection point | Connected to protected line (e.g., 48 V supply rail); polarity notch on package identifies this terminal. |
Key Features
| Feature | Design Value |
|---|---|
| AEC−Q101 qualification | Validated for automotive underhood environments (−65 °C to +150 °C), enabling use in engine control modules and ADAS power supplies. |
| UL 497B recognition | Approved for isolated loop protection in safety-critical industrial communication systems, including RS-485 and 4–20 mA loops. |
| 1500 W peak power rating | Supports robust suppression of high-energy transients such as ISO 7637-2 Pulse 5a (load dump) without degradation. |
| Low leakage <5 µA @ VRWM | Minimizes standby power loss in always-on automotive modules and avoids false triggering in high-impedance sensor interfaces. |
| Sub-ns response time | Clamps transients before logic-level devices experience latch-up or gate oxide damage, critical for protecting CAN FD and LIN transceivers. |
Applications
| Automotive Power Rail Protection | Industrial I/O Interface Protection |
|---|---|
Use Scenario: Protecting 48 V battery-supplied ECUs from load dump transients and alternator ripple. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between battery rail and ground, clamping surges above 51 V. Use Value: Limits peak voltage to 82.4 V during 1500 W transients, preventing damage to downstream PMICs and MCU power inputs. | Use Scenario: Safeguarding RS-485 transceivers in factory automation PLCs from ESD and cable-induced surges. IC Role / Device Role / Timing Role: Line-side TVS connected across differential pair (A/B) and ground to absorb common-mode transients. Use Value: UL 497B certification ensures compliance with isolation barrier requirements for functional safety in process control networks. |
| Medical Equipment Power Input | Telecom DC Power Feeds |
Use Scenario: Shielding AC/DC adapter outputs in portable diagnostic devices from mains-coupled surges. IC Role / Device Role / Timing Role: Secondary-side TVS on regulated 24 V output rail, guarding against internal switching noise and external coupling. Use Value: Low 5 µA leakage preserves battery life in battery-backed medical instruments without compromising surge immunity. | Use Scenario: Protecting PoE-powered network switches from lightning-induced surges on 48 V DC feed lines. IC Role / Device Role / Timing Role: Primary protection device on DC input side, coordinated with upstream GDT and downstream polymer PTC. Use Value: 18.2 A IPP rating enables coordination with 100 kA-rated gas discharge tubes in multi-stage telecom surge protection architectures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SZ1SMB51AT3G | Same electrical specs but SMB package (lower 600 W peak power rating); smaller footprint (3.56 × 3.94 mm vs. 5.84 × 6.86 mm). | Limited to lower-energy transients; unsuitable for ISO 7637-2 Pulse 5a load dump. | Select when board space is constrained and surge energy does not exceed 600 W. |
| SMCJ51A | Identical SMC package and 1500 W rating; same VRWM/VBR/VC, but not AEC−Q101 qualified or UL 497B recognized. | Not approved for automotive underhood or certified isolated-loop systems. | Select for cost-sensitive industrial power supplies where automotive qualification is unnecessary. |
Compared with SZ1SMC51AT3G, SZ1SMB51AT3G offers identical voltage parameters in a smaller package but sacrifices 60% peak power handling, while SMCJ51A matches power and form factor but lacks automotive qualification and UL safety recognition-making SZ1SMC51AT3G the sole choice for AEC−Q101-compliant or UL 497B–certified designs.
Availability
SZ1SMC51AT3G is available at Aetrix Electronics and suitable for automotive power rail protection, industrial I/O interface hardening, and medical equipment power input conditioning requiring stable component supply across extended production lifecycles.
Supply support for SZ1SMC51AT3G 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
onsemi (Nasdaq: ON) is a global semiconductor supplier delivering energy-efficient, intelligent power and sensing solutions for automotive, industrial, cloud, medical, and IoT applications.
The SZ1SMCxxxAT3G series belongs to onsemi's automotive-grade transient voltage suppressor portfolio, engineered specifically for robust, standards-compliant protection of high-reliability electronic systems in harsh environments.
FAQ
What is the clamping voltage of SZ1SMC51AT3G at its rated peak pulse current?
The SZ1SMC51AT3G has a maximum clamping voltage (VC) of 82.4 V when subjected to its rated peak pulse current (IPP) of 18.2 A under a 1 ms waveform. This value is measured per the standard 10/1000 μs surge test condition and defines the upper voltage limit imposed on the protected circuit during transient events. Designers must ensure that this clamping level remains safely below the absolute maximum ratings of downstream components.
Is SZ1SMC51AT3G suitable for bidirectional signal line protection?
No, SZ1SMC51AT3G is a unidirectional TVS diode and is not suitable for bidirectional signal line protection such as USB or HDMI. Its design allows conduction only in reverse bias above breakdown, making it appropriate for DC power rail protection. For bidirectional applications, a symmetric TVS like SZ1SMC51AT3G's bidirectional counterpart (e.g., SZ1SMC51AT3G-BD, if available) or discrete back-to-back configuration would be required-neither of which applies to the SZ1SMC51AT3G itself.
Does SZ1SMC51AT3G meet automotive reliability standards?
Yes, SZ1SMC51AT3G is AEC−Q101 qualified and PPAP capable, confirming its suitability for automotive applications including engine control units, body electronics, and ADAS power supplies. It operates across −65 °C to +150 °C and is manufactured under onsemi's automotive quality management system. The "SZ" prefix explicitly denotes compliance with automotive site and change control requirements beyond standard commercial-grade parts.
What is the thermal resistance from junction to lead for SZ1SMC51AT3G?
The thermal resistance from junction to lead (RJL) for SZ1SMC51AT3G is 54.6 °C/W, measured at TL = 75 °C with zero lead length on a 1 in² copper pad (FR-4 board). This parameter is critical for calculating junction temperature rise during repetitive surge events and informs PCB copper area requirements for thermal management in high-duty-cycle applications.
How does the UL 497B recognition benefit designs using SZ1SMC51AT3G?
UL 497B recognition confirms that SZ1SMC51AT3G meets Underwriters Laboratories' requirements for protectors in isolated loop circuits, including passing strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge tests. This certification enables direct use in safety-critical industrial communication systems (e.g., 4–20 mA loops, RS-485 fieldbus) without additional system-level validation, reducing time-to-certification for end equipment.
SZ1SMC51AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 51V
- Voltage - Breakdown (Min):
- 56.7V
- Voltage - Clamping (Max) @ Ipp:
- 82.4V
- Current - Peak Pulse (10/1000µs):
- 18.2A
- Power - Peak Pulse:
- 1500W (1.5kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMC
SZ1SMC51AT3G FAQ
1.How can I place an order for SZ1SMC51AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for SZ1SMC51AT3G 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 SZ1SMC51AT3G reliable?
The price and inventory of SZ1SMC51AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SZ1SMC51AT3G is usually 5 days.
3.What payment methods are accepted for SZ1SMC51AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SZ1SMC51AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SZ1SMC51AT3G?
SZ1SMC51AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SZ1SMC51AT3G 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 SZ1SMC51AT3G?
For technical support, including SZ1SMC51AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SZ1SMC51AT3G requirements.
6.How does Aetrix verify that SZ1SMC51AT3G is sourced from the original manufacturer or authorized distributors?
All SZ1SMC51AT3G 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 SZ1SMC51AT3G meets industry standards.
7.What is the process for return or replacement of SZ1SMC51AT3G?
All SZ1SMC51AT3G units undergo pre-shipment inspection (PSI). If there is an issue with SZ1SMC51AT3G, 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 SZ1SMC51AT3G part is unused and in its original packaging.
Return procedure for SZ1SMC51AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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