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onsemi SMF20AT1
- Part No.:
- SMF20AT1
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF20AT1.pdf
- Description:
- TVS DIODE 20VWM 32.4VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:3,631
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Product details
Overview
SMF20AT1 from onsemi is a unidirectional transient voltage suppressor (TVS) diode in SOD−123FL package, designed to protect sensitive electronics against ESD and surge events. It features a 20 V working peak reverse voltage (VRWM), 32.4 A maximum peak pulse current (IPP), 32.4 V clamping voltage (VC) at IPP, <1 ns response time, and 200 W peak pulse power (10/1000 µs). It is used in DC power rails of portable power supplies and USB interface protection circuits.
For engineers reviewing the SMF20AT1 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system operating voltage, VC margin relative to IC absolute maximum ratings, IEC61000−4−2 Class 3 (16 kV HBM) compliance, and SOD−123FL footprint compatibility with high-density PCB layouts.
Technical Context
The SMF20AT1 operates as a zener-based clamping device triggered by overvoltage transients exceeding its breakdown voltage (VBR = 22.2–24.5 V). Its low dynamic impedance ensures stable clamping during fast-rising surges such as ESD (IEC61000−4−2 Level 4) and EFT (IEC61000−4−4, 40 A).
Thermal performance is defined by RθJA = 325°C/W (on FR-4 with recommended pad), enabling 385 mW steady-state dissipation at 25°C ambient. The device meets MSL 1 and supports reflow up to 260°C for 10 s, with cathode polarity indicated by a band.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 20 V - Maximum continuous reverse voltage before clamping begins; must be ≥ circuit's DC operating voltage. |
| VBR (min/max) | 22.2 V / 24.5 V - Breakdown occurs within this range at 1 mA test current; defines turn-on threshold tolerance. |
| VC @ IPP | 32.4 V - Clamped voltage seen by protected circuit at 32.4 A peak pulse; determines safe margin below IC damage threshold. |
| IPP | 32.4 A - Peak surge current the device safely shunts per 10/1000 µs waveform; validates robustness against IEC61000−4−5 surges. |
| Response Time | <1 ns - Enables suppression of sub-nanosecond ESD transients before downstream ICs experience overstress. |
| ESD Rating | Class 3 (>16 kV HBM) - Meets stringent electrostatic discharge immunity required for handheld and consumer interfaces. |
| Package | SOD−123FL - Low-profile (1.0 mm max height), small-footprint (8.45 mm²) surface-mount package compatible with automated assembly. |
Pinout & Package
SOD−123FL is a 2-terminal surface-mount package with cathode marked by a polarity band. Total height ≤1.0 mm, footprint area = 8.45 mm², lead finish = 100% matte tin, qualified for 260°C reflow (MSL 1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to system ground or lower-potential rail; clamping occurs when anode-to-cathode voltage exceeds VBR. |
| 2 (Non-banded End) | Anode | Connected to protected signal or power line; conducts surge current to cathode during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOD−123FL package | Enables placement in space-constrained areas like smartphone power rails and USB-C port ESD protection zones. |
| IEC61000−4−2 Level 4 compliance | Guarantees survivability against ±8 kV contact / ±15 kV air discharge, meeting industrial and consumer EMC requirements. |
| Fast <1 ns response | Prevents voltage overshoot beyond IC absolute maximum ratings during nanosecond-scale ESD events. |
| 200 W peak pulse power (10/1000 µs) | Supports protection of 5 V–24 V DC systems against lightning-induced surges and inductive switching transients. |
| Cathode polarity marking | Ensures correct orientation during automated placement and manual inspection, avoiding reverse-bias failure in circuit. |
Applications
| USB Power Delivery Interface | Industrial Sensor Signal Line |
|---|---|
Use Scenario: Protecting VBUS and CC lines in USB-C PD ports from ESD and hot-plug transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamping element placed between connector and PMIC/USB controller. Use Value: Limits VBUS voltage to ≤32.4 V during 32.4 A surges, preserving PD controller integrity while maintaining <1 ns reaction to human-body-model discharges. | Use Scenario: Shielding 4–20 mA analog sensor outputs from field-induced surges in factory automation wiring. IC Role / Device Role / Timing Role: Standoff protector on transmitter output node, referenced to system ground. Use Value: Clamps induced transients to 32.4 V before reaching ADC input, preventing latch-up and ensuring signal continuity under IEC61000−4−4 40 A burst conditions. |
| Portable Medical Device Battery Rail | Automotive Body Control Module Input |
Use Scenario: Safeguarding Li-ion battery monitor ICs and fuel gauges from ESD during battery pack handling and insertion. IC Role / Device Role / Timing Role: Reverse-biased TVS across battery input to ground, activated only during overvoltage faults. Use Value: Withstands >16 kV HBM ESD without degradation, maintaining 20 V standoff for accurate battery voltage sensing during normal operation. | Use Scenario: Protecting LIN bus or switch inputs in BCMs exposed to load-dump and jump-start transients. IC Role / Device Role / Timing Role: Primary clamping device on 12 V supply input, coordinated with upstream fuse and secondary TVS. Use Value: Absorbs 200 W peak energy per 10/1000 µs pulse, limiting voltage to 32.4 V to prevent MCU reset or regulator latch-up during ISO 7637-2 Pulse 1/2a events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ20A | Same VRWM (20 V), higher VC (34.4 V), larger SMA package (4.5 × 2.7 mm vs. SOD−123FL's 2.9 × 1.8 mm). | Less suitable for ultra-thin or high-density layouts; better thermal mass for repeated surge duty. | Select SMAJ20A if board space allows and higher thermal inertia is needed for intermittent surge environments. |
| P6SMB20A | Same VRWM (20 V), identical VC (32.4 V), but DO-214AA package (4.6 × 3.5 mm); 600 W peak power rating. | Over-specified for most portable applications; requires larger PCB real estate and higher assembly cost. | Choose P6SMB20A only when legacy DO-214AA footprint exists or when 600 W surge capability is explicitly required. |
Compared with SMAJ20A and P6SMB20A, the SMF20AT1 delivers identical 20 V standoff and 32.4 V clamping in the smallest possible footprint (SOD−123FL), making it optimal for space-limited, high-volume portable designs where layout density and assembly efficiency are critical.
Availability
SMF20AT1 is available at Aetrix Electronics and suitable for USB-C PD interfaces, industrial 4–20 mA sensor nodes, and portable medical battery monitoring systems requiring stable component supply and full traceability.
Supply support for SMF20AT1 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 belongs to onsemi's transient voltage suppressor portfolio, engineered specifically for compact, high-reliability ESD and surge protection in portable and space-constrained electronics.
FAQ
What is the working peak reverse voltage (VRWM) of the SMF20AT1?
The SMF20AT1 has a working peak reverse voltage (VRWM) of 20 V. This means it remains non-conductive under normal operating conditions up to 20 V DC or peak AC voltage. Exceeding this voltage initiates clamping action. The VRWM value is critical for selecting the correct SMF20AT1 variant to match the protected circuit's operating voltage without leakage or false triggering.
Does the SMF20AT1 meet IEC61000−4−2 ESD immunity standards?
Yes, the SMF20AT1 meets IEC61000−4−2 Level 4 ESD protection, rated for >16 kV per Human Body Model (HBM). This certification is verified per the official onsemi datasheet and confirms its suitability for protecting interfaces exposed to direct user contact, such as USB ports and front-panel controls. The SMF20AT1 achieves this with sub-nanosecond response and low clamping voltage.
What is the maximum clamping voltage (VC) of the SMF20AT1 at its rated peak pulse current?
The SMF20AT1 has a maximum clamping voltage (VC) of 32.4 V at its rated peak pulse current (IPP) of 32.4 A (10/1000 µs waveform). This VC value represents the highest voltage the protected circuit will experience during a worst-case surge event. Designers use this parameter to verify margin between VC and the absolute maximum voltage rating of downstream ICs, ensuring reliable protection.
Can the SMF20AT1 be used in bidirectional protection configurations?
No, the SMF20AT1 is a unidirectional TVS diode and is not suitable for bidirectional protection. Its design provides clamping only for positive transients on the anode relative to cathode. For AC or dual-polarity signal lines (e.g., RS-485, CAN), a bidirectional variant such as SMBJ20CA or dedicated dual-diode arrays must be used instead of the SMF20AT1.
What is the thermal resistance (RθJA) of the SMF20AT1 in standard mounting conditions?
The SMF20AT1 has a junction-to-ambient thermal resistance (RθJA) of 325°C/W when mounted on FR-4 PCB using the manufacturer-recommended minimum pad footprint. This value assumes TA = 25°C and defines the steady-state power dissipation limit of 385 mW. Higher power handling is achievable with enhanced thermal pads or metal-core boards, but the baseline RθJA directly impacts reliability in thermally constrained layouts.
SMF20AT1 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):
- 20V
- Voltage - Breakdown (Min):
- 22.2V
- Voltage - Clamping (Max) @ Ipp:
- 32.4V
- Current - Peak Pulse (10/1000µs):
- 6.2A
- 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
SMF20AT1 FAQ
1.How can I place an order for SMF20AT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF20AT1 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 SMF20AT1 reliable?
The price and inventory of SMF20AT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF20AT1 is usually 5 days.
3.What payment methods are accepted for SMF20AT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF20AT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF20AT1?
SMF20AT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF20AT1 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 SMF20AT1?
For technical support, including SMF20AT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF20AT1 requirements.
6.How does Aetrix verify that SMF20AT1 is sourced from the original manufacturer or authorized distributors?
All SMF20AT1 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 SMF20AT1 meets industry standards.
7.What is the process for return or replacement of SMF20AT1?
All SMF20AT1 units undergo pre-shipment inspection (PSI). If there is an issue with SMF20AT1, 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 SMF20AT1 part is unused and in its original packaging.
Return procedure for SMF20AT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF20AT1 Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
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D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
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ESD5Z5.0T1G
onsemi
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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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