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onsemi SMF170AT1
- Part No.:
- SMF170AT1
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF170AT1.pdf
- Description:
- TVS DIODE 170VWM 275VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:5,737
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Product details
Overview
SMF170AT1 from onsemi is a unidirectional transient voltage suppressor (TVS) diode designed for overvoltage protection in DC power rails and signal lines. It features a 170 V working peak reverse voltage (VRWM), 275 A maximum peak pulse current (IPP), 209 V maximum clamping voltage (VC) at IPP, and 175 W peak pulse power (10/1000 µs). It is used in industrial power supplies to safeguard rectifier outputs and DC bus lines against lightning-induced surges.
For engineers reviewing the SMF170AT1 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin above operating voltage, clamping voltage headroom relative to protected IC absolute maximum ratings, surge current capability under IEC 61000-4-5 Level 4, and SOD−123FL package thermal performance in high-density layouts.
Technical Context
This device operates as a zener-based avalanche clamp, triggered when reverse voltage exceeds its breakdown threshold (VBR = 189–209 V). Its low dynamic impedance ensures stable clamping during fast transients, with sub-1 ns response time enabling protection of sensitive downstream circuitry before damage occurs.
Rated for 175 W peak pulse power (10/1000 µs waveform), it sustains repeated surges only within derated limits - e.g., ≤1000 W at 8/20 µs but with strict duty cycle constraints per Figure 5. Thermal resistance RθJA = 325 °C/W assumes minimum recommended SOD−123FL footprint on FR-4 PCB.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 170 V - Minimum DC or continuous peak operating voltage the device can withstand without conduction; sets lower bound for system rail protection level. |
| VBR @ IT=1 A | 189–209 V - Breakdown occurs within this range at 1 mA test current; defines turn-on threshold consistency across production lots. |
| VC @ IPP=275 A | 209 V max - Maximum voltage seen by protected circuit during full-rated 10/1000 µs surge; determines safe margin below downstream IC absolute max rating. |
| IPP | 275 A - Peak current the device safely shunts during standardized 10/1000 µs transient; correlates directly to IEC 61000-4-5 surge immunity level. |
| Leakage @ VRWM | 1 µA max - Reverse leakage at rated standoff voltage; negligible loading on 170 V bias networks, preserving efficiency and accuracy. |
| Response Time | <1 ns - Time from transient onset to clamping activation; ensures protection of nanosecond-scale logic and analog interfaces. |
| ESD Rating | 16 kV HBM, IEC 61000-4-2 Level 4 - Validated electrostatic discharge immunity for handling and system-level ESD robustness. |
Pinout & Package
SOD−123FL surface-mount package: 2-pin, low-profile (max height 1.0 mm), small footprint (8.45 mm²), cathode indicated by polarity band. Lead finish is 100% matte tin; qualified for 260°C reflow (MSL 1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to protected line's higher-potential side (e.g., +170 V rail); reverse-biased during normal operation; conducts surge current to ground when clamped. |
| 2 (Non-banded End) | Anode | Connected to reference potential (typically GND or low-side return); completes current path during transient suppression event. |
Key Features
| Feature | Design Value |
|---|---|
| Low Clamping Ratio | VC/VRWM = 1.23 - Tight ratio minimizes overvoltage stress on protected components while maintaining sufficient margin above operating voltage. |
| High Surge Robustness | 175 W @ 10/1000 µs - Enables compliance with IEC 61000-4-5 surge immunity requirements for industrial equipment up to Level 4 (4 kV line-earth). |
| Ultra-Fast Response | <1 ns activation - Prevents voltage overshoot beyond downstream IC absolute maximum ratings during ESD or fast-rising transients. |
| Low Capacitance | ~10 pF @ 0 V - Negligible signal distortion on high-speed data lines (e.g., RS-485, CAN FD) when placed in parallel with protected traces. |
| Thermal Reliability | RθJcathode = 26 °C/W - Efficient heat transfer from junction to cathode pad enables sustained operation in thermally constrained PCB areas. |
Applications
| Industrial Power Supply Protection | Telecom Line Interface |
|---|---|
|
Use Scenario: Protecting output rectifiers and bulk capacitors in 170 VDC industrial switch-mode power supplies against lightning-induced surges on AC input or DC bus lines. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between DC+ and chassis ground, clamping transients before they reach downstream regulators and controllers. Use Value: Limits transient voltage to ≤209 V during 275 A surges, preventing catastrophic failure of 200 V-rated electrolytic capacitors and MOSFETs on the same rail. |
Use Scenario: Safeguarding RS-485 transceivers and isolation amplifiers connected to long outdoor telecom cables exposed to induced surges. IC Role / Device Role / Timing Role: Standoff protector on differential bus lines (A/B), referenced to local ground, absorbing common-mode transients before they couple into signal paths. Use Value: Sub-1 ns response ensures clamping occurs before transceiver input stages experience latch-up or gate oxide rupture during 10/1000 µs surges. |
| Motor Drive DC Bus Clamp | Renewable Energy Inverter Input |
|
Use Scenario: Suppressing inductive kickback and switching transients on 170 VDC bus lines feeding H-bridge motor drivers in HVAC and pump control systems. IC Role / Device Role / Timing Role: Parallel-connected TVS on main DC link capacitor terminals, diverting energy from IGBT freewheeling diodes and snubbers. Use Value: 275 A peak current rating handles repetitive commutation spikes without degradation, extending bus capacitor lifetime and reducing EMI filter stress. |
Use Scenario: Protecting MPPT controller inputs and DC-link monitoring circuits in solar microinverters subjected to grid-side surge coupling. IC Role / Device Role / Timing Role: Primary overvoltage clamp on PV string input stage, positioned upstream of input filtering and isolation transformers. Use Value: 170 V VRWM matches typical open-circuit voltage of 12–14 PV module strings, ensuring reliable blocking during normal operation while clamping fault conditions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC170 | Same VRWM (170 V), but 200 W peak power (10/1000 µs), 250 A IPP, higher VC (220 V), SOD-123FL package. | Lower surge rating suits cost-sensitive consumer-grade inverters where IEC 61000-4-5 Level 3 suffices. | Select SAC170 if board space and thermal budget allow slightly higher clamping voltage and reduced surge margin is acceptable. |
| P6SMB170A | Same VRWM (170 V), but DO-214AA package, 600 W peak power (10/1000 µs), 340 A IPP, 275 V VC, larger footprint. | Higher power handling supports multi-kW industrial drives requiring extended surge endurance beyond single-event rating. | Choose P6SMB170A when PCB layout permits larger package and system-level testing demands >175 W transient absorption capacity. |
Compared with SMF170AT1, SAC170 offers lower cost but reduced surge robustness and higher clamping voltage, while P6SMB170A delivers superior power handling at the expense of board area and thermal density - making SMF170AT1 optimal for space-constrained, high-reliability 170 VDC systems needing precise clamping control.
Availability
SMF170AT1 is available at Aetrix Electronics and suitable for industrial power supplies, telecom line interfaces, motor drive DC bus protection, and renewable energy inverter inputs requiring stable component supply and consistent surge performance across production batches.
Supply support for SMF170AT1 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 computing, and IoT markets.
The SMF series is part of onsemi's transient voltage suppression portfolio, engineered specifically for compact, high-reliability DC rail protection in space-constrained applications where SOD−123FL footprint and sub-1 ns response are critical design requirements.
FAQ
What is the working peak reverse voltage (VRWM) of the SMF170AT1?
The SMF170AT1 has a VRWM of 170 V, meaning it blocks up to 170 V DC or peak AC voltage in normal operation without significant leakage. This value is selected to match or slightly exceed the maximum steady-state voltage of the protected circuit - for example, the output of a 170 VDC industrial power supply - ensuring reliable blocking while allowing margin for ripple and tolerance.
What is the maximum clamping voltage (VC) for the SMF170AT1 under full-rated surge current?
The SMF170AT1 exhibits a maximum clamping voltage (VC) of 209 V when subjected to its rated peak pulse current of 275 A (10/1000 µs waveform). This VC value represents the highest voltage that will appear across the protected line during a worst-case transient, and must be verified against the absolute maximum ratings of downstream components such as MOSFETs, capacitors, or controllers to ensure safe operation.
Is the SMF170AT1 suitable for protecting RS-485 communication lines?
Yes, the SMF170AT1 is suitable for RS-485 line protection when applied across differential pairs referenced to local ground, thanks to its low capacitance (~10 pF), sub-1 ns response time, and ability to clamp fast transients without distorting signal edges. However, its 170 V VRWM makes it appropriate only for high-voltage RS-485 implementations (e.g., long-haul industrial links), not standard ±12 V buses - for those, lower VRWM variants like SMF12A would be selected instead.
How does the SOD−123FL package affect thermal performance of the SMF170AT1?
The SOD−123FL package of the SMF170AT1 delivers RθJA = 325 °C/W when mounted on the minimum recommended FR-4 footprint, limiting continuous power dissipation to 385 mW at 25°C ambient. For surge events, thermal mass dominates - but repeated surges require careful PCB copper pour design and possibly thermal vias to the inner ground plane to avoid junction temperature excursions beyond 150°C, especially in enclosed industrial enclosures.
Does the SMF170AT1 meet IEC 61000-4-5 surge immunity standards?
The SMF170AT1 is rated for 175 W peak pulse power at the 10/1000 µs waveform defined in IEC 61000-4-5, which corresponds to Level 4 (4 kV line-to-earth) for many industrial applications. While the device itself meets the energy-handling requirement, full system compliance depends on PCB layout, grounding strategy, and coordination with upstream filters - the SMF170AT1 serves as the final clamping element in a staged protection architecture.
SMF170AT1 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):
- 170V
- Voltage - Breakdown (Min):
- 189V
- Voltage - Clamping (Max) @ Ipp:
- 275V
- Current - Peak Pulse (10/1000µs):
- 600mA
- 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
SMF170AT1 FAQ
1.How can I place an order for SMF170AT1 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF170AT1 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 SMF170AT1 reliable?
The price and inventory of SMF170AT1 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF170AT1 is usually 5 days.
3.What payment methods are accepted for SMF170AT1?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF170AT1 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF170AT1?
SMF170AT1 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF170AT1 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 SMF170AT1?
For technical support, including SMF170AT1 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF170AT1 requirements.
6.How does Aetrix verify that SMF170AT1 is sourced from the original manufacturer or authorized distributors?
All SMF170AT1 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 SMF170AT1 meets industry standards.
7.What is the process for return or replacement of SMF170AT1?
All SMF170AT1 units undergo pre-shipment inspection (PSI). If there is an issue with SMF170AT1, 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 SMF170AT1 part is unused and in its original packaging.
Return procedure for SMF170AT1:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF170AT1 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
-
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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