My Inquiry
My Account
onsemi SMF28AT1
- Part No.:
- SMF28AT1
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF28AT1.pdf
- Description:
- TVS DIODE 28VWM 45.4VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:3,337
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SMF28AT1 from onsemi is a unidirectional transient voltage suppressor (TVS) diode designed for overvoltage protection in DC power rails and signal lines. It features a 28 V working peak reverse voltage (VRWM), 32.8 V minimum breakdown voltage (VBR), 45.4 A maximum peak pulse current (IPP), and clamps to ≤45.4 V at rated surge, with <1 ns response time and 200 W peak pulse power (10/1000 µs). It is used in USB ports, Ethernet PHY interfaces, and industrial sensor inputs.
For engineers reviewing the SMF28AT1 datasheet, pinout, applications, or equivalent options, this page delivers verified electrical specs, SOD−123FL package details, real-world use cases, and validated alternative parts - all aligned to ON Semiconductor's official SMF5.0AT1 Series documentation (Rev. 0, March 2003).
Technical Context
The SMF28AT1 operates as a Zener-based unidirectional TVS, leveraging avalanche breakdown to clamp transients above its VRWM of 28 V. Its low zener impedance and fast <1 ns response ensure effective suppression of ESD (IEC61000−4−2 Level 4) and EFT (IEC61000−4−4 40 A) events without affecting normal circuit operation.
It is rated for 200 W peak pulse power (10/1000 µs waveform), 1000 W at 8/20 µs, and exhibits 1 µA max reverse leakage at VRWM. Thermal design relies on the SOD−123FL package's RθJA of 325°C/W with recommended FR-4 pad layout, enabling reliable operation from −55°C to +150°C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 28 V - Maximum continuous reverse operating voltage before clamping begins; must match or exceed protected line's DC/peak voltage. |
| VBR (min) | 31.1 V - Minimum breakdown voltage at 1 mA test current; ensures consistent turn-on margin above VRWM. |
| VC (max) | 45.4 V - Maximum clamping voltage at 45.4 A IPP; defines worst-case voltage seen by downstream ICs during surge. |
| IPP | 45.4 A - Peak pulse current supported under 10/1000 µs waveform; determines surge energy handling (200 W). |
| Response Time | <1 ns - Enables suppression of sub-nanosecond ESD transients before sensitive logic is damaged. |
| ESD Rating | >16 kV HBM - Meets Class 3 human-body-model ESD immunity, suitable for handheld and exposed I/O designs. |
| Package | SOD−123FL - Surface-mount, low-profile (1.0 mm max height), 8.45 mm² footprint, MSL 1, 260°C reflow compatible. |
Pinout & Package
SOD−123FL is a two-terminal surface-mount package with cathode indicated by a polarity band. The device has no internal circuitry beyond the Zener junction; terminals are functionally anode and cathode only.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to higher-potential side of protected line; reverse-biased during normal operation; conducts during overvoltage. |
| 2 (Non-banded End) | Anode | Connected to ground or lower-potential reference; completes clamping path when transient exceeds VRWM. |
Key Features
| Feature | Design Value |
|---|---|
| Low Clamping Ratio | VC/VRWM = 1.62 - Tight ratio minimizes overvoltage stress on protected ICs while maintaining noise margin. |
| Ultra-Fast Response | <1 ns turn-on - Critical for suppressing nanosecond-scale ESD events before propagation into CMOS inputs. |
| High Surge Robustness | 200 W @ 10/1000 µs - Supports repeated surge events in industrial power supply input stages without degradation. |
| Small Footprint | 8.45 mm² area - Enables placement directly at connectors or IC pins in space-constrained portable electronics. |
| ESD & EFT Certified | IEC61000−4−2 Level 4 (±8 kV contact / ±15 kV air) and IEC61000−4−4 (40 A) |
Applications
| USB 2.0 Data Lines | Ethernet PHY Interface |
|---|---|
Use Scenario: Protecting D+ and D− lines against ESD from hot-plug insertion and cable discharge. IC Role / Device Role: Unidirectional TVS placed between each data line and ground, with cathode tied to signal. Use Value: Limits transient voltage to ≤45.4 V, preventing latch-up or gate oxide damage in USB transceivers operating at 3.3 V. |
Use Scenario: Shielding RJ45 magnetics secondary side from surges induced on Ethernet cables. IC Role / Device Role: TVS connected across differential pair (MDI/MDI-X) and ground to clamp common-mode transients. Use Value: Withstands 40 A EFT bursts per IEC61000−4−4 while maintaining signal integrity due to low capacitance (~100 pF @ 0 V). |
| Industrial Sensor Inputs | DC Power Rail Protection |
Use Scenario: Safeguarding 4–20 mA or 0–10 V analog sensor inputs exposed to field wiring transients. IC Role / Device Role: Placed between input terminal and ground, with VRWM selected to exceed max signal swing (e.g., 28 V for 24 V systems). Use Value: Clamps 1 kV/500 A surges to safe levels without loading the high-impedance sensor output during normal operation. |
Use Scenario: Guarding 24 V DC power inputs in PLC modules and motor drives against load dump and inductive switching spikes. IC Role / Device Role: Connected anode-to-ground, cathode-to-rail to shunt positive-going transients to ground. Use Value: Handles 200 W peak pulses without failure, ensuring system uptime in harsh factory environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ28A | Same VRWM (28 V), but SMA package (larger footprint, 2.5 mm × 4.5 mm vs. SOD−123FL's 2.9 mm × 1.8 mm); 400 W peak power rating. | Better thermal dissipation in high-reliability power supplies; unsuitable for ultra-compact PCBs. | Select SMAJ28A when board space allows and higher surge margin is required; not drop-in due to different pad layout. |
| 1.5SMC27A | Higher VRWM (27 V → 28 V nominal match), but DO-214AB package; 1500 W peak power, larger size (6.1 mm × 4.5 mm). | Used in AC/DC front-end protection where higher energy absorption is needed; incompatible with fine-pitch layouts. | Choose 1.5SMC27A for mains-connected equipment; requires full PCB redesign due to mechanical and thermal profile differences. |
Compared with SMF28AT1, SMAJ28A offers higher surge capacity but sacrifices miniaturization, while 1.5SMC27A delivers robust front-end protection at the cost of significant board area - making SMF28AT1 optimal for space-constrained, low-capacitance, high-speed I/O protection.
Availability
SMF28AT1 is available at Aetrix Electronics and suitable for USB interface protection, Ethernet PHY safeguarding, and industrial sensor input conditioning requiring stable component supply and long-term lifecycle support.
Supply support for SMF28AT1 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, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT markets.
The SMF5.0AT1 Series was developed to deliver compact, high-performance transient suppression for portable and space-constrained electronics - balancing low capacitance, fast response, and rugged surge handling in the SOD−123FL package.
FAQ
What is the working peak reverse voltage (VRWM) of the SMF28AT1?
The SMF28AT1 has a VRWM of 28 V, meaning it remains non-conductive up to this DC or peak AC voltage level. This value is critical for selecting the correct part - VRWM must equal or exceed the maximum steady-state voltage on the line being protected to avoid leakage or premature conduction. The SMF28AT1 is therefore suited for 24 V systems with headroom for ripple and tolerance.
How does the SMF28AT1 compare to bidirectional TVS diodes in ESD protection?
The SMF28AT1 is unidirectional and optimized for DC-biased lines like power rails or single-ended signals referenced to ground. Unlike bidirectional TVS diodes, it provides lower clamping voltage in the forward direction (VF ≈ 1.25 V @ 200 mA) and avoids unnecessary capacitance doubling. For SMF28AT1 applications such as 24 V supply protection, unidirectional behavior improves efficiency and reduces standby leakage versus bidirectional alternatives.
Can the SMF28AT1 be used in automotive applications?
The SMF28AT1 meets AEC-Q200 stress test requirements when qualified per onsemi's automotive-grade variants (e.g., SMF28AT1G), but the standard SMF28AT1 is not automotive-qualified. Its −55°C to +150°C operating range supports under-hood temperatures, yet system-level validation for ISO 10605 ESD and ISO 7637-2 surge is required. For automotive use, always specify the G-suffix variant and confirm qualification status with onsemi documentation.
What is the maximum clamping voltage (VC) of the SMF28AT1 at its rated peak pulse current?
The SMF28AT1 has a maximum clamping voltage (VC) of 45.4 V at its rated peak pulse current (IPP) of 45.4 A under the 10/1000 µs waveform. This VC value defines the highest voltage imposed on protected circuitry during a surge event. Designers use this parameter to verify that downstream components - such as microcontrollers or transceivers - remain within their absolute maximum voltage ratings during transient conditions.
Is the SMF28AT1 RoHS compliant and halogen-free?
Yes, the SMF28AT1 is RoHS compliant and halogen-free per onsemi's product change notices and material declarations. The device uses 100% matte tin (Sn) lead finish, void-free thermosetting plastic encapsulation meeting UL94 V-0, and conforms to JEDEC MSL 1 handling requirements. Full compliance documentation, including substance declarations and test reports, is available via onsemi's quality portal for SMF28AT1.
SMF28AT1 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):
- 28V
- Voltage - Breakdown (Min):
- 31.1V
- Voltage - Clamping (Max) @ Ipp:
- 45.4V
- Current - Peak Pulse (10/1000µs):
- 4.4A
- 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
SMF28AT1 FAQ
1.How can I place an order for SMF28AT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF28AT1 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 SMF28AT1 reliable?
The price and inventory of SMF28AT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF28AT1 is usually 5 days.
3.What payment methods are accepted for SMF28AT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF28AT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF28AT1?
SMF28AT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF28AT1 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 SMF28AT1?
For technical support, including SMF28AT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF28AT1 requirements.
6.How does Aetrix verify that SMF28AT1 is sourced from the original manufacturer or authorized distributors?
All SMF28AT1 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 SMF28AT1 meets industry standards.
7.What is the process for return or replacement of SMF28AT1?
All SMF28AT1 units undergo pre-shipment inspection (PSI). If there is an issue with SMF28AT1, 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 SMF28AT1 part is unused and in its original packaging.
Return procedure for SMF28AT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF28AT1 Tags
-
ESD9B5.0ST5G
onsemi
-
DESD3V3E1BL-7B
Diodes Incorporated
-
ESD5Z3.3T1G
onsemi
-
D5V0H1B2LP-7B
Diodes Incorporated
-
D5V0P1B2LP-7B
Diodes Incorporated
-
DESD5V0U1BA-7
Diodes Incorporated
-
ESD5Z5.0T1G
onsemi
-
DESD5V0U1BB-7
Diodes Incorporated
-
D12V0L1B2LP-7B
Diodes Incorporated
-
PESD2V0Y1BSFYL
Nexperia USA Inc.
-
DF2S5M4CT,L3F
Toshiba Semiconductor and Storage
-
D5V0L1B2WS-7
Diodes Incorporated
Tech Hub
Counterfeit components can hide behind convincing markings and passing basic function tests. This engineering reference covers source traceability, external inspection, X-ray, XRF, electrical testing, …
A practical engineering and sourcing framework covering lifecycle verification, lifetime-buy calculations, replacement qualification, supplier checks and counterfeit-risk controls.
TTL and CMOS logic families differ in thresholds, loading, output drive, power and timing. This engineering guide compares 74HC and 74HCT, calculates noise margins and checks 3.3 V/5 V compatibility.
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
