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onsemi 1SMA43AT3
- Part No.:
- 1SMA43AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
1SMA43AT3.pdf
- Description:
- TVS DIODE 43VWM 69.4VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:4,056
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Product details
Overview
1SMA43AT3 from ON Semiconductor is a unidirectional 400 W peak power Zener transient voltage suppressor (TVS) designed for clamping high-energy transients in DC power rails and signal lines. It features a 43 V working peak reverse voltage (VRWM), 50.3 V nominal breakdown voltage (VBR) at 1 A test current, 69.4 A maximum peak pulse current (IPP), and clamps to 69.4 V at that current. It is used in automotive power supply protection and industrial control I/O interfaces.
For engineers reviewing the 1SMA43AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system operating voltage, VC ≤ protected IC's absolute maximum rating, fast <1 ns response, and SMA package compatibility with automated SMT assembly on FR-4 PCBs.
Technical Context
The 1SMA43AT3 operates as a unidirectional avalanche diode, conducting only during negative transients relative to its anode–cathode polarity. Its clamping behavior is defined by the 10/1000 µs surge waveform per R.E.A., with thermal derating applied above 75°C junction temperature.
It exhibits low zener impedance and fast response (<1 ns), enabling effective suppression of ESD (Class 3, >16 kV HBM) and lightning-induced surges. The device is rated for 40 A forward surge current (IFSM) and requires no external biasing-functioning solely as a passive crowbar element during overvoltage events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Peak Power Dissipation | 400 W @ 1 ms pulse - sustains single high-energy transients without failure |
| Working Peak Reverse Voltage (VRWM) | 43 V - maximum continuous reverse voltage before significant leakage; sets minimum system operating margin |
| Breakdown Voltage (VBR) | 47.8–52.8 V @ 1 A - defines onset of avalanche conduction; nominal 50.3 V ensures predictable turn-on |
| Clamping Voltage (VC) | 69.4 V @ 69.4 A IPP - maximum voltage seen by protected circuit during worst-case surge |
| Response Time | <1 ns - enables suppression of nanosecond-scale ESD and fast-rising transients |
| ESD Rating | Class 3 (>16 kV HBM) - meets IEC 61000-4-2 Level 4 for robust board-level ESD immunity |
| Thermal Resistance (Junction-to-Lead) | 20 °C/W - supports 1.5 W DC dissipation at 75°C lead temperature with proper PCB copper area |
Pinout & Package
SMA package (Case 403D-02), surface-mount, unidirectional polarity indicated by cathode band. Low-profile plastic housing with flat handling surface for accurate pick-and-place placement.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction or surge clamping | Connected to lower-potential side of protected line (e.g., GND or return path) |
| Cathode | Current exit terminal during reverse-biased clamping | Connected to higher-potential side (e.g., +43 V rail); marked by molded band |
Key Features
| Feature | Design Value |
|---|---|
| 400 W peak pulse power | Enables protection against IEC 61000-4-5 Level 3 (1 kV/2 Ω) surges on 24–48 V systems |
| Low clamping ratio (VC/VBR ≈ 1.38) | Minimizes overvoltage stress on downstream ICs compared to higher-ratio TVS devices |
| Pb-free (1SMA43AT3G available) | Complies with RoHS Directive 2011/65/EU without compromising surge performance |
| Flat handling surface | Ensures consistent coplanarity and solder joint reliability in reflow processes |
| Top-slide or bottom-mount compatible | Supports flexible PCB layout with either side-up or side-down orientation in tape-and-reel feeders |
Applications
| Automotive Power Rail Protection | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: Suppresses load dump and alternator ripple transients on 42 V battery-fed ECUs and body control modules. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and ground, clamping positive spikes above 43 V. Use Value: Limits rail voltage to ≤69.4 V during 400 W surges, preventing damage to 75 V-rated DC-DC controllers and CAN transceivers. |
Use Scenario: Shields 24 V digital input channels in programmable logic controllers from field-wiring induced surges. IC Role / Device Role / Timing Role: Standoff device across input optocoupler terminals, activated only during overvoltage events. Use Value: Maintains <2.5 µA leakage at 43 V, ensuring clean logic thresholds while clamping 69.4 V transients within 1 ns. |
| Medical Equipment Power Supply Input | Telecom Line Card Surge Protection |
Use Scenario: Protects isolated DC-DC converters in patient-connected devices from AC mains coupling and ESD. IC Role / Device Role / Timing Role: Primary-side TVS on 48 V intermediate bus, coordinated with fuse and MOV staging. Use Value: Provides Class 3 ESD immunity and withstands repetitive 10/1000 µs surges up to 400 W without parameter shift. |
Use Scenario: Guards Ethernet PHY power pins and auxiliary bias rails in carrier-grade line cards exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Secondary-stage clamping device after gas discharge tube (GDT), limiting let-through voltage. Use Value: Achieves 69.4 V clamping at 69.4 A, reducing residual voltage below 80 V threshold of 100BASE-TX PHYs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ43A (Bourns) | Same VRWM (43 V), but 600 W peak power and SMB package (larger footprint) | Better surge handling in space-tolerant designs; requires larger PCB pad area | Select when higher single-pulse energy margin is needed and board space allows SMB outline |
| P4KE43A (Littelfuse) | Through-hole DO-41 package, same 43 V VRWM, 400 W rating, slower response (~1.2 ns) | Not suitable for high-density SMT layouts; limited to prototyping or legacy through-hole assemblies | Choose only for manual assembly or backward compatibility with DO-41 footprints |
Compared with SMBJ43A and P4KE43A, the 1SMA43AT3 offers optimal balance of 400 W surge capability, compact SMA footprint, and sub-1 ns response-making it preferred for modern SMT-based automotive and industrial control boards where space and speed are critical.
Availability
1SMA43AT3 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial PLC I/O protection, and medical equipment power supply input requiring stable component supply and full RoHS compliance.
Supply support for 1SMA43AT3 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 part of onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensor, and connectivity solutions for automotive, industrial, and cloud power applications.
The 1SMA43AT3 belongs to the SMA-series unidirectional TVS family, engineered specifically for high-reliability transient suppression in harsh environments-including under-hood automotive, factory automation, and medical power systems.
FAQ
What is the maximum clamping voltage of the 1SMA43AT3 under surge conditions?
The 1SMA43AT3 clamps to a maximum of 69.4 V when subjected to its rated peak pulse current of 69.4 A, measured using the standard 10/1000 µs waveform. This value is guaranteed across temperature and represents the highest voltage the protected circuit will experience during a worst-case transient. The 1SMA43AT3 achieves this clamping performance while maintaining low dynamic impedance and sub-1 ns response time.
Is the 1SMA43AT3 suitable for bidirectional transient protection?
No, the 1SMA43AT3 is strictly unidirectional and must be connected with correct polarity-cathode to the higher-potential line, anode to ground or return. For bidirectional protection, ON Semiconductor offers separate devices such as the 1SMA43CAT3. Using the 1SMA43AT3 in reverse-biased configurations beyond its VRWM will cause excessive leakage or failure; always verify polarity in schematic and layout for the 1SMA43AT3.
What is the recommended PCB footprint for the 1SMA43AT3?
The 1SMA43AT3 uses the SMA package (Case 403D-02), and ON Semiconductor specifies a minimum recommended footprint on FR-4 board for thermal performance. Key dimensions include 4.06–4.57 mm length (A), 2.29–2.92 mm width (B), and 1.91–2.41 mm height (C). A 1″ square copper pad is required for junction-to-lead thermal resistance testing; actual layout should follow the soldering footprint diagram on page 5 of the official 1SMA5.0AT3 Series datasheet.
Does the 1SMA43AT3 meet RoHS requirements?
Yes, the 1SMA43AT3 is available in both standard and Pb-free versions-the latter designated as 1SMA43AT3G. The Pb-free variant complies with EU RoHS Directive 2011/65/EU and is processed using onsemi's qualified lead-free soldering profile. Both versions share identical electrical specifications; the "G" suffix indicates the environmentally compliant packaging option for the 1SMA43AT3.
How does the 1SMA43AT3 compare to the 1SMA40AT3 in terms of voltage rating and application fit?
The 1SMA43AT3 has a 43 V VRWM and 47.8–52.8 V VBR range, whereas the 1SMA40AT3 is rated for 40 V VRWM and 44.4–49.1 V VBR. This 3 V higher standoff makes the 1SMA43AT3 preferable for 42–48 V systems where margin against normal operating ripple is critical. Both share identical 400 W peak power and SMA packaging, so the 1SMA43AT3 replaces the 1SMA40AT3 directly when tighter voltage tolerance or higher system rail stability is required.
1SMA43AT3 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):
- 43V
- Voltage - Breakdown (Min):
- 47.8V
- Voltage - Clamping (Max) @ Ipp:
- 69.4V
- Current - Peak Pulse (10/1000µs):
- 5.8A
- Power - Peak Pulse:
- 400W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 295pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMA
1SMA43AT3 FAQ
1.How can I place an order for 1SMA43AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMA43AT3 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 1SMA43AT3 reliable?
The price and inventory of 1SMA43AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMA43AT3 is usually 5 days.
3.What payment methods are accepted for 1SMA43AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMA43AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMA43AT3?
1SMA43AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMA43AT3 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 1SMA43AT3?
For technical support, including 1SMA43AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMA43AT3 requirements.
6.How does Aetrix verify that 1SMA43AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMA43AT3 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 1SMA43AT3 meets industry standards.
7.What is the process for return or replacement of 1SMA43AT3?
All 1SMA43AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMA43AT3, 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 1SMA43AT3 part is unused and in its original packaging.
Return procedure for 1SMA43AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMA43AT3 Tags
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onsemi
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