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onsemi SMF43AT1G
- Part No.:
- SMF43AT1G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF43AT1G.pdf
- Description:
- TVS DIODE 43VWM 69.4VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:4,313
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Product details
Overview
SMF43AT1G from onsemi is a unidirectional Zener transient voltage suppressor (TVS) diode in SOD-123FL package, designed to protect sensitive electronics against ESD and surge transients. It features a 43 V working peak reverse voltage (VRWM), 50.3 V minimum breakdown voltage (VBR), 52.8 V maximum clamping voltage (VC) at 2.9 A peak pulse current (IPP), and 200 W peak pulse power (10/1000 µs). It is used in DC power rails of portable industrial sensors and USB-powered peripherals.
For engineers reviewing the SMF43AT1G datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to system operating voltage, IEC61000-4-2 Level 4 ESD robustness (>16 kV HBM), low leakage (<1 µA @ VRWM), sub-1 ns response time, and compatibility with automated SMT assembly using Pb-free reflow profiles up to 260°C.
Technical Context
The SMF43AT1G operates as a unidirectional avalanche-clamped Zener diode, entering conduction when reverse voltage exceeds its specified breakdown threshold (VBR = 47.8–52.8 V). Its low dynamic impedance ensures stable clamping during fast transients such as ESD (IEC61000-4-2) and EFT (IEC61000-4-4).
It delivers 200 W peak pulse power for 10/1000 µs waveform per JEDEC standards, with thermal resistance of 325 °C/W (junction-to-ambient, FR-4 board) and 26 °C/W (junction-to-cathode lead), enabling reliable operation across -55°C to +150°C ambient range without derating below 25°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 43 V - Maximum continuous reverse operating voltage before clamping begins; must exceed system DC rail voltage (e.g., 36 V nominal 48 V bus) |
| VBR (min/max) | 47.8 V / 52.8 V - Breakdown occurs within this band at 1 mA test current; defines turn-on threshold tolerance |
| VC @ IPP | 52.8 V @ 2.9 A - Clamped voltage during 10/1000 µs surge; determines maximum stress seen by protected IC |
| IPP | 2.9 A - Peak pulse current supported at rated clamping voltage; correlates directly to surge energy handling |
| Leakage @ VRWM | <1 µA - Negligible standby power loss and signal integrity impact on high-impedance nodes |
| Response Time | <1 ns - Fast enough to suppress ESD events before downstream logic or analog circuitry is damaged |
| ESD Rating | Class 3 HBM (>16 kV) - Meets IEC61000-4-2 Level 4 for user-accessible ports |
Pinout & Package
SOD-123FL surface-mount plastic package (Case 498), 1.0 mm max height, 2.7 mm × 1.6 mm footprint (8.45 mm²), Pb-free matte tin finish, MSL 1 rated, compatible with 260°C reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to protected line (e.g., VBUS); clamps to ground when overvoltage exceeds VRWM |
| 2 (Non-banded End) | Anode | Connected to system ground reference; forms low-impedance path for surge current during clamping |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOD-123FL package | 1.0 mm max height enables use in space-constrained portable designs (e.g., handheld test equipment, wearables) |
| IEC61000-4-2 Level 4 ESD protection | Withstands ±8 kV contact / ±15 kV air discharge without degradation - eliminates need for external ESD filters on USB/UART lines |
| Fast <1 ns response | Clamps before transient propagates beyond PCB trace length typical in compact layouts (<10 cm) |
| Pb-free and RoHS-compliant | Meets global environmental compliance requirements without requiring special soldering process changes |
| 3000-unit tape-and-reel packaging | Optimized for high-volume automated pick-and-place assembly with cathode orientation aligned to sprocket holes |
Applications
| Industrial Sensor Interface | USB-C Power Delivery Input |
|---|---|
Use Scenario: Protecting 24–48 V DC input of an RS-485 field sensor node exposed to lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VCC and GND, clamping transients before they reach the isolated DC-DC converter and communication IC. Use Value: Withstands 200 W (10/1000 µs) surge while limiting clamped voltage to ≤52.8 V - ensuring downstream 60 V-rated input capacitors and regulators remain within safe operating area. | Use Scenario: Safeguarding the VBUS line of a USB-C port in a portable medical monitor accepting up to 20 V PD input. IC Role / Device Role / Timing Role: Primary overvoltage clamp on the 5–20 V VBUS rail, positioned upstream of load switch and PD controller. Use Value: 43 V VRWM allows full 20 V PD negotiation headroom; 52.8 V VC prevents latch-up or damage to 24 V tolerant PD controller ICs during ESD or hot-plug transients. |
| Automated Test Equipment (ATE) Front-End | Smart Building Controller Power Input |
Use Scenario: Shielding analog front-end inputs of a benchtop multimeter from accidental 120 VAC misconnection or induced transients. IC Role / Device Role / Timing Role: Secondary protection stage after fuse and primary MOV, providing precise low-leakage clamping on low-current measurement paths. Use Value: Sub-1 µA leakage at 43 V avoids measurement offset errors; <1 ns response preserves integrity of fast-rising calibration pulses. | Use Scenario: Securing the 24 V AC/DC power input of a DIN-rail mounted HVAC controller subjected to building-wide switching surges. IC Role / Device Role / Timing Role: First-line transient suppressor on main DC input, placed immediately after bridge rectifier and bulk capacitor. Use Value: 200 W peak power rating handles repetitive 40 A EFT bursts (IEC61000-4-4); low thermal resistance (325 °C/W) sustains reliability under continuous 50°C ambient cabinet conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43A | Same VRWM (43 V) and VC (52.8 V), but SMA package (larger footprint, 2.5 mm × 4.5 mm vs. SOD-123FL's 1.6 mm × 2.7 mm) | Less suitable for ultra-compact PCBs; higher thermal mass may improve surge endurance in non-space-constrained designs | Choose SMAJ43A only if board layout permits larger footprint and higher mounting height (2.2 mm vs. 1.0 mm) |
| 1.5SMC43A | Higher peak power (1500 W vs. 200 W), DO-214AB package, same VRWM and VC specs | Intended for high-energy industrial mains protection, not portable electronics; incompatible with fine-pitch SMT lines | Select 1.5SMC43A only for fixed-installation equipment where surge threat level exceeds IEC61000-4-5 Level 3 (1 kV differential mode) |
Compared with SMAJ43A and 1.5SMC43A, the SMF43AT1G provides optimal balance of compact size, ESD robustness, and precision clamping for battery-powered and space-limited applications - its SOD-123FL package enables placement directly at connector entry points without sacrificing PCB real estate.
Availability
SMF43AT1G is available at Aetrix Electronics and suitable for industrial sensor interfaces, USB-C power delivery inputs, automated test equipment front-ends, and smart building controller power inputs requiring stable component supply and guaranteed Pb-free compliance.
Supply support for SMF43AT1G 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 SMF series belongs to onsemi's transient voltage suppression portfolio, engineered specifically for high-reliability, low-leakage, fast-response protection of low-voltage DC rails in portable and space-constrained systems.
FAQ
What is the clamping voltage of SMF43AT1G at its rated peak pulse current?
The SMF43AT1G has a maximum clamping voltage (VC) of 52.8 V at its rated peak pulse current (IPP) of 2.9 A for a 10/1000 µs waveform. This value is measured under standardized surge conditions and defines the upper voltage limit imposed on protected circuitry during transient events. The SMF43AT1G maintains this clamping performance across its qualified temperature range (-55°C to +150°C), making it suitable for harsh-environment deployments where thermal stability is critical.
Is SMF43AT1G compatible with lead-free reflow soldering processes?
Yes, the SMF43AT1G is Pb-free and qualified for lead-free reflow soldering with a maximum peak temperature of 260°C, meeting IPC/JEDEC J-STD-020 moisture sensitivity level (MSL) 1 requirements. Its matte tin lead finish ensures reliable wetting and intermetallic formation during standard reflow profiles. The SMF43AT1G's thermal resistance (RJA = 325 °C/W on FR-4) supports consistent thermal performance post-reflow, and its SOD-123FL package geometry minimizes tombstoning risk in high-speed placement.
How does the SMF43AT1G differ from bidirectional TVS diodes in circuit protection design?
The SMF43AT1G is unidirectional and functions only during reverse overvoltage events - it behaves like a Zener diode above VRWM and presents low forward voltage (~1.25 V @ 200 mA) in forward bias. Unlike bidirectional TVS devices, it does not clamp positive transients on grounded lines, making it ideal for DC power rail protection where polarity is fixed. In contrast, bidirectional variants (e.g., SMBJ43CA) would conduct on both polarities, increasing leakage and potentially interfering with normal signal swing in single-supply systems. The SMF43AT1G's unidirectional behavior ensures minimal interference with steady-state operation.
Can SMF43AT1G be used to protect a 36 V nominal DC system?
Yes, the SMF43AT1G is appropriate for protecting a 36 V nominal DC system because its 43 V working peak reverse voltage (VRWM) exceeds the system's maximum expected continuous voltage (including ripple and tolerance), while its 52.8 V clamping voltage remains safely below the absolute maximum ratings of typical 60 V-rated power management ICs and capacitors. Transient suppression margin is calculated as VRWM − VDC(max) = 43 V − 39.6 V = 3.4 V, satisfying industry best practices for robust overvoltage headroom. The SMF43AT1G's low leakage (<1 µA) also prevents measurable loading on the 36 V rail.
What is the ESD robustness rating of SMF43AT1G per international standards?
The SMF43AT1G is rated to IEC61000-4-2 Level 4 for electrostatic discharge immunity: ±8 kV contact discharge and ±15 kV air discharge. It also meets Class 3 Human Body Model (HBM) with >16 kV rating. These values are verified per standardized test methods and reflect actual device-level performance - not system-level certification. The SMF43AT1G achieves this via low-junction-capacitance design and optimized Zener structure, enabling direct placement at I/O connectors without degrading signal integrity. Its ESD capability is intrinsic to the die and unaffected by PCB layout parasitics.
SMF43AT1G Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- SOD-123F
- 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):
- 2.9A
- Power - Peak Pulse:
- 200W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SOD-123FL
SMF43AT1G FAQ
1.How can I place an order for SMF43AT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF43AT1G 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 SMF43AT1G reliable?
The price and inventory of SMF43AT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF43AT1G is usually 5 days.
3.What payment methods are accepted for SMF43AT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF43AT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF43AT1G?
SMF43AT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF43AT1G 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 SMF43AT1G?
For technical support, including SMF43AT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF43AT1G requirements.
6.How does Aetrix verify that SMF43AT1G is sourced from the original manufacturer or authorized distributors?
All SMF43AT1G 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 SMF43AT1G meets industry standards.
7.What is the process for return or replacement of SMF43AT1G?
All SMF43AT1G units undergo pre-shipment inspection (PSI). If there is an issue with SMF43AT1G, 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 SMF43AT1G part is unused and in its original packaging.
Return procedure for SMF43AT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF43AT1G Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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ESD5Z3.3T1G
onsemi
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D5V0H1B2LP-7B
Diodes Incorporated
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D5V0P1B2LP-7B
Diodes Incorporated
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DESD5V0U1BA-7
Diodes Incorporated
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ESD5Z5.0T1G
onsemi
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DESD5V0U1BB-7
Diodes Incorporated
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D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
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DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
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D5V0L1B2WS-7
Diodes Incorporated
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