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onsemi 1SMA51AT3G
- Part No.:
- 1SMA51AT3G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA51AT3G.pdf
- Description:
- TVS DIODE 51VWM 82.4VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:7,350
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Product details
Overview
1SMA51AT3G from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) in SMA package, designed for clamping high-energy transients in DC power rails and signal lines. It features a 51 V working peak reverse voltage (VRWM), 59.7 V nominal breakdown voltage (VBR) at 1 A test current, 82.4 A maximum peak pulse current (IPP), and clamps to 121 V at IPP - used in automotive power supply protection and industrial I/O interface surge suppression.
For engineers reviewing the 1SMA51AT3G datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system operating voltage, VC ≤ protected circuit's absolute maximum rating, low zener impedance for fast clamping, ESD Class 3 (>16 kV HBM) robustness, and SMA surface-mount compatibility with FR-4 PCB thermal derating profiles.
Technical Context
This TVS diode operates as a unidirectional clamping device, conducting only during reverse overvoltage events above its VBR threshold while presenting high impedance under normal bias. Its 1 ns typical response time and low dynamic impedance ensure effective suppression of EFT/burst and lightning-induced surges per IEC 61000-4-4/5.
The device uses a planar Zener junction structure optimized for stable breakdown and repeatable clamping performance across temperature (−65°C to +150°C). Thermal design relies on junction-to-lead resistance (RJL = 20 °C/W) and junction-to-ambient resistance (RJA = 250 °C/W) with defined derating curves for continuous and pulsed operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 51 V - minimum reverse standoff voltage before clamping begins; must exceed system's max DC or peak AC operating voltage. |
| VBR @ IT=1 A | 59.7 V (nominal) - precise Zener breakdown threshold defining turn-on point for transient suppression. |
| VC @ IPP | 121 V - maximum clamped voltage at 82.4 A peak pulse; determines worst-case stress on downstream ICs. |
| PPK | 400 W @ 1 ms - peak surge energy handling capability per single non-repetitive 10/1000 µs waveform. |
| IR @ VRWM | 2.5 µA - leakage current at rated standoff voltage; ensures minimal quiescent power loss in standby. |
| ESD Rating | Class 3 (>16 kV HBM) - qualifies for high-robustness interfaces like automotive body control modules and industrial fieldbus nodes. |
Pinout & Package
SMA package (Case 403D-02), surface-mount, low-profile plastic housing with molded cathode band polarity indicator. Dimensions: 4.06–4.57 mm × 2.29–2.92 mm × 1.91–2.41 mm (L×W×H); flat handling surface enables accurate pick-and-place placement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal / low-side reference | Connected to ground or lower-potential rail; defines reference for reverse-biased clamping operation. |
| Cathode | Reverse-bias input / transient injection node | Connected to protected line (e.g., 12 V battery rail); conducts surge current to anode when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Supports IEC 61000-4-5 Level 4 (4 kV line-earth) surge testing without failure in properly designed layouts. |
| <1 ns response time | Clamps transients before sensitive logic or analog circuitry experiences damaging overvoltage excursion. |
| Pb-free (RoHS-compliant) packaging | Enables compliance with global environmental regulations and lead-free reflow soldering processes (260°C/10 s). |
| Low zener impedance | Maintains tight VC tolerance across IPP range, ensuring predictable clamping behavior under varying surge magnitudes. |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital Input Protection |
|---|---|
Use Scenario: Protecting 12 V/24 V battery-fed ECUs against load dump and alternator ripple transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed between power rail and chassis ground to clamp surges >60 V. Use Value: Limits voltage seen by PMICs and microcontrollers to ≤121 V, preventing latch-up or oxide breakdown. | Use Scenario: Shielding 24 V digital input channels in programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Standoff protection device mounted at connector entry point, shunting transient energy to common ground. Use Value: Enables reliable operation in factory environments with frequent EFT bursts and cable coupling noise. |
| Medical Equipment Power Supply Input | Telecom Line Interface Surge Suppression |
Use Scenario: Safeguarding isolated DC-DC converter inputs in patient-connected devices against mains-coupled transients. IC Role / Device Role / Timing Role: Primary-stage TVS on secondary-side 5 V/12 V rails upstream of LDO regulators. Use Value: Meets IEC 60601-1 creepage/clearance requirements while providing <1 ns reaction to fast-rising spikes. | Use Scenario: Front-end protection for RS-485 transceivers in building automation networks exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Unidirectional clamping element between differential pair and local ground plane. Use Value: Maintains signal integrity by limiting common-mode overvoltage without distorting data timing windows. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ51A | Same VRWM (51 V) and VC (121 V), but 600 W PPK in SMB package; higher thermal mass. | Better suited for higher-duty-cycle surge environments due to larger case size and lower RJA. | Select SMBJ51A when board space allows and thermal budget requires >400 W single-pulse margin. |
| 1N6330 | Same electrical specs (51 V VRWM, 121 V VC), but DO-204AC (DO-15) through-hole package. | Requires wave soldering or hand assembly; not compatible with automated SMT lines. | Choose 1N6330 only for legacy through-hole designs or prototyping where rework flexibility is prioritized. |
Compared with SMBJ51A and 1N6330, the 1SMA51AT3G offers optimal balance of compact SMA footprint, 400 W surge capability, and RoHS-compliant surface-mount manufacturability - ideal for space-constrained automotive and industrial PCBs requiring high-volume SMT assembly.
Availability
1SMA51AT3G is available at Aetrix Electronics and suitable for automotive power rail protection, industrial PLC digital input protection, and medical equipment power supply input requiring stable component supply and full traceability.
Supply support for 1SMA51AT3G 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 solutions for automotive, industrial, and cloud power applications.
The 1SMAxxAT3 series was engineered specifically for cost-sensitive, high-reliability transient suppression in surface-mount power systems - emphasizing low-profile packaging, consistent clamping, and robust surge endurance in harsh environments.
FAQ
What is the maximum clamping voltage of the 1SMA51AT3G under surge conditions?
The 1SMA51AT3G clamps to a maximum of 121 V at its rated peak pulse current of 82.4 A (10/1000 µs waveform). This value is measured per standard test conditions and represents the upper limit of voltage imposed on protected circuitry during a 400 W transient event. Designers must ensure downstream components tolerate this clamped voltage under worst-case surge scenarios.
Does the 1SMA51AT3G support lead-free reflow soldering processes?
Yes, the 1SMA51AT3G is Pb-free and qualified for lead-free reflow soldering with a maximum peak temperature of 260°C for 10 seconds. Its Surmetic SMA package meets J-STD-020 moisture sensitivity level (MSL) requirements and is compatible with standard FR-4 PCB thermal profiles used in high-volume SMT assembly lines.
How does the 1SMA51AT3G differ from bidirectional TVS diodes like the 1SMA51CAT3?
The 1SMA51AT3G is unidirectional and functions only during reverse overvoltage events, blocking forward current beyond ~3.5 V VF. In contrast, the 1SMA51CAT3 is bidirectional and clamps symmetrically in both polarities - making it suitable for AC lines or differential signals. The 1SMA51AT3G is preferred for DC power rail protection where polarity is fixed and lower capacitance is beneficial.
What is the thermal derating behavior of the 1SMA51AT3G above 75°C ambient?
Above 75°C, the 1SMA51AT3G's DC power dissipation derates linearly at 20 mW/°C from its 1.5 W rating at TL = 75°C. At 100°C lead temperature, its usable DC power drops to 1.0 W. For pulsed operation, Figure 3 in the datasheet shows peak power derating to ~70% of 400 W at 100°C ambient, based on thermal time constants of the SMA package.
Can the 1SMA51AT3G be used in parallel to increase surge current handling?
No - paralleling 1SMA51AT3G devices is not recommended due to mismatched VBR tolerances (±5% typical), which cause uneven current sharing and potential thermal runaway. For higher IPP, select a single higher-rated device such as SMBJ51A (600 W) or 1.5KE51A (1500 W) with matched thermal characteristics and layout symmetry.
1SMA51AT3G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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):
- -
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 250pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA51AT3G FAQ
1.How can I place an order for 1SMA51AT3G through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA51AT3G 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 1SMA51AT3G reliable?
The price and inventory of 1SMA51AT3G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA51AT3G is usually 5 days.
3.What payment methods are accepted for 1SMA51AT3G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA51AT3G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA51AT3G?
1SMA51AT3G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA51AT3G 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 1SMA51AT3G?
For technical support, including 1SMA51AT3G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA51AT3G requirements.
6.How does Aetrix verify that 1SMA51AT3G is sourced from the original manufacturer or authorized distributors?
All 1SMA51AT3G 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 1SMA51AT3G meets industry standards.
7.What is the process for return or replacement of 1SMA51AT3G?
All 1SMA51AT3G units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA51AT3G, 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 1SMA51AT3G part is unused and in its original packaging.
Return procedure for 1SMA51AT3G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA51AT3G Tags
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