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onsemi SMF40AT1
- Part No.:
- SMF40AT1
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF40AT1.pdf
- Description:
- TVS DIODE 40VWM 64.5VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:7,734
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Product details
Overview
SMF40AT1 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 40 V working peak reverse voltage (VRWM), 64.5 A maximum peak pulse current (IPP), 72.7 V maximum clamping voltage (VC) at IPP, <1 ns response time, and 200 W peak pulse power (10/1000 µs). It is used in DC power rail protection for portable power supplies and USB interface circuits.
For engineers reviewing the SMF40AT1 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to protected IC's absolute maximum rating, VRWM alignment with nominal supply voltage, IEC 61000−4−2 Level 4 ESD robustness, and SOD−123FL thermal performance under repeated surge stress.
Technical Context
The SMF40AT1 operates as a unidirectional avalanche diode, conducting only in reverse breakdown above its specified VBR (44.4–49.1 V) while remaining high-impedance below VRWM (40 V). Its low zener impedance ensures stable clamping during fast transients such as ESD (16 kV HBM) and 40 A IEC 61000−4−4 bursts.
Thermal design relies on the SOD−123FL package's RθJA of 325°C/W (with recommended pad) and junction-to-cathode RθJcathode of 26°C/W. Power dissipation derates linearly above 25°C ambient, maintaining safe operation up to +150°C junction temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 40 V - Maximum continuous reverse voltage before clamping begins; must exceed system DC rail (e.g., 36 V nominal 40 V max supply) |
| VBR (min/max) | 44.4 V / 49.1 V - Breakdown occurs within this range at 1 mA test current; defines turn-on threshold consistency |
| VC @ IPP | 72.7 V max - Clamped voltage seen by protected circuit during 64.5 A 10/1000 µs surge; determines overvoltage stress on downstream ICs |
| IPP | 64.5 A - Peak surge current capability at 10/1000 µs waveform; supports IEC 61000−4−5 Level 3 (1 A/kV) compliance with margin |
| Response Time | <1 ns - Enables suppression of nanosecond-scale ESD events before sensitive logic inputs are damaged |
| ESD Rating | Class 3 HBM (>16 kV) - Meets IEC 61000−4−2 Level 4 contact discharge requirement without external shielding |
| Package | SOD−123FL - Surface-mount flat-lead package with 1.0 mm max height and 8.45 mm² footprint; compatible with standard reflow profiles (MSL 1, 260°C peak) |
Pinout & Package
SOD−123FL is a 2-terminal surface-mount package with cathode indicated by a polarity band. Mounting orientation is unrestricted; leads are 100% matte tin with void-free thermosetting epoxy meeting UL94 VO.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Cathode) | Surge return path / clamping node | Connected to protected line (e.g., VBUS); conducts transient energy to ground when voltage exceeds VRWM |
| 2 (Anode) | Reference / ground reference | Typically tied to system ground plane; establishes reference for reverse-bias operation and defines clamping level |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOD−123FL | 1.0 mm max height enables use in ultra-thin portable devices where board space and Z-height are constrained |
| IEC 61000−4−2 Level 4 compliance | Withstands ±8 kV contact and ±15 kV air discharge without degradation-eliminates need for secondary ESD filters |
| Fast 10/1000 µs surge rating | 200 W peak power handling supports industrial-grade surge immunity per IEC 61000−4−5 with minimal PCB area |
| Low leakage <1 µA @ VRWM | Minimizes standby power loss in battery-powered systems; avoids false triggering on nominal 40 V rails |
| Tape-and-reel packaging | 3,000 units per reel enables automated pick-and-place assembly with consistent polarity orientation (cathode toward sprocket holes) |
Applications
| USB Power Input Protection | Industrial 24–48 V DC Rail Clamp |
|---|---|
|
Use Scenario: Protecting USB Type-C VBUS lines (5–20 V) and auxiliary power paths in docking stations against hot-plug surges and ESD. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VBUS and chassis/earth ground to clamp transients before they reach USB controller or PD controller ICs. Use Value: Limits clamped voltage to ≤72.7 V during 64.5 A surges-well below absolute maximum ratings of common USB PD ICs (e.g., FUSB302, TUSB546). |
Use Scenario: Safeguarding programmable logic controllers (PLCs) and sensor nodes powered from 24 V or 48 V industrial DC supplies exposed to inductive switching noise. IC Role / Device Role / Timing Role: Primary surge clamp on main DC input rail, positioned upstream of DC/DC converters and LDOs. Use Value: Withstands repetitive 10/1000 µs surges up to 200 W while maintaining VRWM ≥40 V-compatible with 48 V nominal systems operating up to 57 V max. |
| Automotive Body Control Module (BCM) Inputs | Medical Portable Device Battery Charging Port |
|
Use Scenario: Protecting LIN bus transceivers and switch inputs in BCMs subjected to load dump and ISO 7637−2 pulses. IC Role / Device Role / Timing Role: Secondary-level transient suppressor on 12 V auxiliary rails, complementing primary TVS arrays. Use Value: Delivers 64.5 A IPP and <1 ns response-sufficient to suppress ISO 7637−2 Pulse 1 (inductive spike) and Pulse 2a (battery disconnect) waveforms. |
Use Scenario: Securing lithium-ion battery charging ports in handheld diagnostic tools against accidental ESD during field use. IC Role / Device Role / Timing Role: Final-stage ESD guard on charging input, placed immediately before battery fuel gauge or charger IC. Use Value: Class 3 HBM (>16 kV) and IEC 61000−4−2 Level 4 compliance ensure reliability across >100,000 plug/unplug cycles without parameter drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ40A | Same VRWM (40 V), but SMA package (larger footprint, higher RθJA = 40°C/W), 400 W peak power (10/1000 µs) | Better surge handling but requires 2.5× more PCB area; less suitable for space-constrained portable designs | Choose SMAJ40A only if system-level surge testing exceeds 200 W and board layout allows SMA footprint. |
| 1.5SMC40A | Same VRWM (40 V), DO−214AB package, 1500 W peak power (10/1000 µs), higher VC (77.4 V) | Higher clamping voltage reduces margin for 5 V logic; suited for high-energy industrial mains-side protection | Select 1.5SMC40A when protecting 48 V distribution buses with high stored energy, not low-voltage IC interfaces. |
Compared with SMAJ40A and 1.5SMC40A, the SMF40AT1 delivers optimal balance of compact size, precise clamping (72.7 V), and certified ESD robustness-making it preferred for consumer and portable electronics where board area, height, and HBM compliance are critical.
Availability
SMF40AT1 is available at Aetrix Electronics and suitable for USB power input protection, industrial 24–48 V DC rail clamp, and medical portable device battery charging port applications requiring stable component supply and full traceability.
Supply support for SMF40AT1 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, analog, sensing, and connectivity solutions for automotive, industrial, cloud, and IoT markets.
The SMF series belongs to onsemi's transient voltage suppressor product line, engineered specifically for high-reliability, low-profile ESD and surge protection in space-constrained, high-volume electronic systems.
FAQ
What is the clamping voltage of SMF40AT1 at its rated peak pulse current?
The SMF40AT1 has a maximum clamping voltage (VC) of 72.7 V when subjected to its rated peak pulse current (IPP) of 64.5 A under the 10/1000 µs waveform. This value is measured per Figure 2 in the official datasheet and represents the worst-case voltage imposed on the protected circuit during surge events-critical for ensuring downstream ICs remain within their absolute maximum voltage ratings.
Is SMF40AT1 suitable for bidirectional signal line protection?
No, SMF40AT1 is a unidirectional TVS diode and is not suitable for bidirectional signal lines such as RS-485 or CAN bus. Its design conducts only in reverse breakdown; forward conduction is limited to typical diode behavior (~1.25 V @ 200 mA). For bidirectional protection, a symmetric TVS like SMBJ40CA or dedicated bidirectional array must be used instead of SMF40AT1.
What is the maximum operating temperature for SMF40AT1?
The SMF40AT1 has an operating and storage temperature range of −55°C to +150°C. Its thermal performance is validated up to +150°C junction temperature, with power derating beginning above +25°C ambient. At +85°C ambient, its DC power dissipation is reduced to approximately 231 mW based on the 325°C/W RθJA rating and TJ(max) = 150°C.
Does SMF40AT1 meet IEC 61000−4−2 Level 4 ESD requirements?
Yes, SMF40AT1 is rated for Class 3 HBM (>16 kV) and meets IEC 61000−4−2 Level 4 ESD protection (±8 kV contact, ±15 kV air discharge). This certification is explicitly stated in the "Specification Features" section of the datasheet and verified per JEDEC JS-001 test methodology-making SMF40AT1 appropriate for end-equipment requiring full Level 4 compliance without additional ESD components.
How is polarity identified on the SMF40AT1 SOD−123FL package?
Polarity on the SMF40AT1 is indicated by a cathode band printed on the package body adjacent to terminal 1. Per the marking diagram and mechanical drawings, terminal 1 is the cathode and must be connected to the line being protected (e.g., VBUS), while terminal 2 (anode) connects to ground. In tape-and-reel delivery, the cathode lead is oriented toward the sprocket holes to ensure consistent automated placement.
SMF40AT1 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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 3.1A
- 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
SMF40AT1 FAQ
1.How can I place an order for SMF40AT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF40AT1 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 SMF40AT1 reliable?
The price and inventory of SMF40AT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF40AT1 is usually 5 days.
3.What payment methods are accepted for SMF40AT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF40AT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF40AT1?
SMF40AT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF40AT1 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 SMF40AT1?
For technical support, including SMF40AT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF40AT1 requirements.
6.How does Aetrix verify that SMF40AT1 is sourced from the original manufacturer or authorized distributors?
All SMF40AT1 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 SMF40AT1 meets industry standards.
7.What is the process for return or replacement of SMF40AT1?
All SMF40AT1 units undergo pre-shipment inspection (PSI). If there is an issue with SMF40AT1, 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 SMF40AT1 part is unused and in its original packaging.
Return procedure for SMF40AT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF40AT1 Tags
-
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
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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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