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onsemi SMF43AT1
- Part No.:
- SMF43AT1
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF43AT1.pdf
- Description:
- TVS DIODE 43VWM 69.4VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:7,674
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Product details
Overview
SMF43AT1 from onsemi is a unidirectional transient voltage suppressor (TVS) diode designed for overvoltage protection in DC power rails and signal lines. It features a 43 V working peak reverse voltage (VRWM), 69.4 A maximum peak pulse current (IPP), 52.8 V maximum clamping voltage (VC) at IPP, and 200 W peak pulse power (10/1000 µs). It is used to protect USB ports, industrial I/O interfaces, and 48 V telecom power inputs against ESD and lightning-induced surges.
For engineers reviewing the SMF43AT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical parameters, SOD−123FL package dimensions, cathode/anode terminal roles, real-world clamping behavior under 10/1000 µs transients, and two validated alternative TVS diodes with documented VRWM and IPP trade-offs.
Technical Context
The SMF43AT1 operates as a Zener-based unidirectional TVS, conducting only in reverse breakdown above VRWM to clamp transient energy into ground. Its low zener impedance and sub-1 ns response time enable effective suppression of fast-rising ESD (IEC61000−4−2 Level 4) and EFT (IEC61000−4−4) events.
It is rated for 175 W peak pulse power under 10/1000 µs waveform (per note 1 in datasheet), 1000 W under 8/20 µs waveform, and exhibits <1 µA leakage at 43 V. Thermal resistance from junction to ambient is 325 °C/W when mounted on FR-4 with recommended pad layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 43 V - Maximum continuous reverse operating voltage before clamping begins; matches 48 V nominal supply rails with 10% tolerance margin. |
| VBR @ IT=1 A | 47.8–52.8 V - Breakdown occurs within this range at 1 mA test current; ensures reliable turn-on before system damage threshold. |
| VC @ IPP=69.4 A | 52.8 V max - Clamped voltage seen by protected circuit during worst-case 10/1000 µs surge; limits stress on downstream ICs. |
| IPP | 69.4 A - Peak surge current it safely shunts without failure; supports IEC61000−4−5 line-to-ground 1 kV/2 Ω test compliance. |
| Leakage @ VRWM | ≤1 µA - Negligible standby current draw; avoids battery drain in always-on portable systems. |
| Response Time | <1 ns - Fast enough to intercept ESD events before logic-level ICs experience latch-up or gate oxide rupture. |
| ESD Rating | >16 kV HBM - Meets Class 3 human-body-model ESD immunity; protects front-end connectors without external shielding. |
Pinout & Package
SOD−123FL surface-mount package: 2.5–2.9 mm length × 1.5–1.8 mm width × ≤1.0 mm height; molded thermosetting plastic case (UL94 VO); matte tin lead finish; MSL 1; reflow compatible up to 260°C for 10 s.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to protected line (e.g., VBUS); reverse-biased during normal operation; conducts to ground during overvoltage. |
| 2 (Non-banded End) | Anode | Connected to system ground; provides return path for surge current; must be low-inductance PCB trace to maintain clamping efficacy. |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOD−123FL footprint | 8.45 mm² area and ≤1.0 mm height - enables placement near connectors and dense PCB layouts without mechanical interference. |
| High surge capability | 200 W peak power (10/1000 µs) - withstands repeated industrial-grade transients without parameter shift or degradation. |
| Fast response & low clamping | <1 ns turn-on + 52.8 V VC - minimizes overvoltage overshoot on 3.3 V/5 V logic rails downstream of protection. |
| ESD-hardened construction | Class 3 HBM (>16 kV) + IEC61000−4−2 Level 4 - eliminates need for secondary ESD components in handheld device designs. |
| Tape-and-reel packaging | 3,000 units per 8 mm reel - supports automated SMT assembly with standard pick-and-place feeders. |
Applications
| Industrial I/O Protection | Telecom Power Input |
|---|---|
Use Scenario: 24–48 V DC input to PLC digital input modules exposed to inductive switching noise and field wiring surges. IC Role / Device Role / Timing Role: Unidirectional TVS placed between input terminal and ground to clamp transients before they reach optocoupler or MCU GPIO. Use Value: Limits voltage to ≤52.8 V during 1 kV/2 Ω surge, preventing optocoupler CTR degradation and false triggering. |
Use Scenario: Primary-side protection on 48 V telecom rectifier outputs feeding PoE injectors or base station backplanes. IC Role / Device Role / Timing Role: Front-line transient suppressor across bulk DC rail to absorb lightning-induced ring waves and load dump spikes. Use Value: Absorbs 200 W pulses without failure, maintaining rail integrity while downstream DC-DC converters remain undisturbed. |
| USB Type-C VBUS Protection | Automotive Body Control Module |
Use Scenario: VBUS line in USB-C receptacles subjected to hot-plug ESD and cable discharge events. IC Role / Device Role / Timing Role: Reverse-biased TVS from VBUS to GND, activated only during overvoltage to avoid loading 5/9/15/20 V PD negotiation. Use Value: Clamps 15 kV contact ESD to ≤52.8 V in <1 ns, protecting USB PD controller and port power switches. |
Use Scenario: LIN bus or sensor supply lines in BCMs exposed to load dump and jump-start transients. IC Role / Device Role / Timing Role: Low-leakage (≤1 µA) TVS on 12 V auxiliary rails to prevent false resets during engine cranking. Use Value: Maintains <1 µA leakage at 13.5 V nominal, eliminating battery drain while clamping 200 V/100 ms load dump to safe levels. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ43A | Same VRWM (43 V), but SMA package (larger footprint, 400 W peak power, RθJA = 50°C/W). | Better thermal handling for high-duty-cycle surges; unsuitable for ultra-thin or space-constrained boards. | Select SMAJ43A when board layout allows larger 4.5×2.7 mm footprint and higher surge repetition is expected. |
| 1.5SMC43A | Same VRWM (43 V), DO-214AB package, 1500 W peak power, 2.5 µA leakage @ VRWM. | Higher power rating suits automotive alternator load dump; higher leakage may affect low-power sleep modes. | Choose 1.5SMC43A for 12 V/24 V automotive systems requiring ISO 7637-2 compliance, not portable electronics. |
Compared with SMF43AT1, SMAJ43A offers superior thermal dissipation in larger packages but sacrifices board space, while 1.5SMC43A delivers higher surge robustness at the cost of leakage and size-making SMF43AT1 optimal for compact, low-leakage, high-volume consumer and industrial applications.
Availability
SMF43AT1 is available at Aetrix Electronics and suitable for industrial I/O protection, telecom power input, USB Type-C VBUS protection, and automotive body control module designs requiring stable component supply, consistent parametric performance, and full traceability.
Supply support for SMF43AT1 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 (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensors, and connectivity solutions for automotive, industrial, cloud, and IoT markets.
The SMF series is part of onsemi's transient voltage suppressor portfolio, engineered specifically for compact, high-reliability overvoltage protection in space-constrained and high-surge-environment applications.
FAQ
What is the clamping voltage of SMF43AT1 at its rated peak pulse current?
The SMF43AT1 has a maximum clamping voltage (VC) of 52.8 V when subjected to its rated peak pulse current (IPP) of 69.4 A under the 10/1000 µs waveform. This value is guaranteed across temperature and ensures protected circuits see no more than 52.8 V during worst-case surge events. The SMF43AT1 achieves this with low dynamic impedance and tight process control, making it suitable for safeguarding 48 V system rails where overvoltage margin is critical.
Is SMF43AT1 unidirectional or bidirectional, and how does that affect its circuit placement?
The SMF43AT1 is a unidirectional TVS diode, meaning it conducts only when reverse-biased beyond its breakdown voltage-i.e., when cathode voltage exceeds anode voltage by ≥47.8 V. It must be placed with cathode toward the protected line (e.g., VBUS or 48 V rail) and anode tied to clean ground. Unlike bidirectional devices, it does not protect against positive transients on grounded lines, so correct polarity orientation is essential. This configuration ensures zero forward conduction during normal operation and precise clamping during overvoltage.
What is the leakage current specification for SMF43AT1 at its working peak reverse voltage?
The SMF43AT1 specifies a maximum reverse leakage current (IR) of 1 µA at its working peak reverse voltage (VRWM) of 43 V, measured at TA = 25°C. This ultra-low leakage prevents measurable power loss in battery-powered or energy-harvesting systems and avoids false triggering in high-impedance sensing nodes. The value remains stable across −55°C to +125°C operating range, supporting reliable performance in extended-temperature industrial deployments.
Can SMF43AT1 be used in IEC61000−4−5 compliant surge protection circuits?
Yes, the SMF43AT1 supports IEC61000−4−5 compliance when implemented with appropriate series impedance (e.g., 2 Ω coupling resistor) and PCB layout. Its 69.4 A IPP rating and 52.8 V clamping voltage meet the 1 kV open-circuit/0.5 Ω source impedance test requirement for AC mains and signal line protection. For full system-level compliance, it should be paired with upstream filtering and proper grounding-verified via actual surge testing-not datasheet extrapolation alone.
What is the thermal resistance and power derating behavior of SMF43AT1 in typical PCB mounting?
The SMF43AT1 has a junction-to-ambient thermal resistance (RθJA) of 325 °C/W when mounted on FR-4 with the manufacturer-recommended minimum pad layout. At 25°C ambient, its steady-state power dissipation is 385 mW; this derates linearly above 25°C at 4.0 mW/°C. For example, at 85°C ambient, usable power drops to ~145 mW. Effective heat sinking-such as thermal vias or copper pour-can improve thermal performance, but the SOD−123FL package inherently limits sustained power handling compared to larger packages.
SMF43AT1 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
SMF43AT1 FAQ
1.How can I place an order for SMF43AT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF43AT1 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 SMF43AT1 reliable?
The price and inventory of SMF43AT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF43AT1 is usually 5 days.
3.What payment methods are accepted for SMF43AT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF43AT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF43AT1?
SMF43AT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF43AT1 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 SMF43AT1?
For technical support, including SMF43AT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF43AT1 requirements.
6.How does Aetrix verify that SMF43AT1 is sourced from the original manufacturer or authorized distributors?
All SMF43AT1 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 SMF43AT1 meets industry standards.
7.What is the process for return or replacement of SMF43AT1?
All SMF43AT1 units undergo pre-shipment inspection (PSI). If there is an issue with SMF43AT1, 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 SMF43AT1 part is unused and in its original packaging.
Return procedure for SMF43AT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF43AT1 Tags
-
ESD9B5.0ST5G
onsemi
-
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
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
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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