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onsemi SMF85AT1G
- Part No.:
- SMF85AT1G
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- SOD-123F
- Datasheet:
-
SMF85AT1G.pdf
- Description:
- TVS DIODE 85VWM 137VC SOD123FL
- Quantity:
- Payment:
- Shipping:
Inventory:5,509
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Product details
Overview
SMF85AT1G from onsemi is a unidirectional Zener transient voltage suppressor (TVS) diode in SOD-123FL package, designed for clamping high-energy transients in DC power rails and signal lines. It features 85 V working peak reverse voltage (VRWM), 137 A maximum peak pulse current (IPP), and 104 V maximum clamping voltage (VC) at IPP - enabling robust protection of 75–90 V systems such as industrial power supplies and telecom interfaces.
For engineers reviewing the SMF85AT1G datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM margin over operating voltage, clamping voltage headroom relative to protected IC absolute maximum ratings, surge capability under IEC 61000-4-4 (40 A), and low-profile SOD-123FL footprint compatibility with space-constrained PCB layouts.
Technical Context
The SMF85AT1G operates as a unidirectional avalanche breakdown device, triggered when reverse voltage exceeds its 94.4–104 V breakdown range (VBR). Its fast <1 ns response time ensures suppression before sensitive downstream circuitry sustains damage from ESD or lightning-induced surges.
It meets IEC 61000-4-2 Level 4 (±16 kV contact/±25 kV air) and IEC 61000-4-4 (40 A, 5/50 ns) immunity standards. Thermal design relies on low junction-to-cathode thermal resistance (26 °C/W) and MSL 1 reflow compatibility up to 260 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 85 V - Minimum reverse standoff voltage; must exceed max continuous DC rail voltage (e.g., 72 V telecom supply) to avoid leakage conduction during normal operation. |
| VBR @ IT=1 A | 94.4–104 V - Breakdown onset range; defines threshold where TVS begins conducting significantly to clamp transients. |
| VC @ IPP=137 A | 104 V - Maximum clamped voltage seen by protected circuit during full-rated 10/1000 µs surge; determines required voltage margin for downstream ICs. |
| IPP | 137 A - Peak pulse current handling per 10/1000 µs waveform; supports IEC 61000-4-4 compliance at 40 A with significant safety margin. |
| Leakage @ VRWM | 1 µA max - Ensures negligible power loss and no interference with high-impedance sensing or bias networks at rated working voltage. |
| ESD Rating | Class 3 HBM (>16 kV) - Validated for direct human-body discharge events without degradation, critical for handheld and field-serviceable equipment. |
| Package | SOD-123FL - 2.7 × 1.6 mm footprint, 1.0 mm max height; enables dense placement near connectors or IC power pins with minimal board area impact. |
Pinout & Package
SOD-123FL surface-mount package with cathode indicated by polarity band; lead finish is 100% matte tin; qualified for MSL 1 and 260 °C reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (Banded End) | Cathode | Connected to system ground or low-side reference; reverse-biased during normal operation; conducts surge current to ground when clamping. |
| 2 (Non-Banded End) | Anode | Connected to protected line (e.g., +85 V rail); carries transient energy into the device during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SOD-123FL | 1.0 mm max height enables use in ultra-thin consumer and telecom modules where Z-height is constrained. |
| 200 W peak pulse power | Rated for 200 W (10/1000 µs) per JEDEC standard - sufficient for EN 61000-4-5 line surge testing in secondary-side protection. |
| Fast <1 ns response | Clamps transients before propagation into ICs with nanosecond-scale input protection, preserving signal integrity in high-speed interfaces. |
| Pb-Free (RoHS-compliant) | Matte Sn lead finish meets global environmental regulations and supports lead-free assembly without solderability compromise. |
Applications
| Industrial Power Supply Protection | Telecom DC Feeder Line Protection |
|---|---|
Use Scenario: Protecting 72–90 V DC distribution rails in programmable logic controllers (PLCs) and motor drives from load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed across input terminals to clamp positive-going surges to ≤104 V. Use Value: Prevents latch-up or permanent damage to upstream DC-DC controllers and downstream FPGA I/O banks rated for 100 V absolute max. | Use Scenario: Safeguarding central office line cards and remote radio units against induced surges on -48 V or +85 V telecom feeder lines. IC Role / Device Role / Timing Role: Standoff-clamp device mounted at connector entry point to shunt IEC 61000-4-4 40 A bursts directly to chassis ground. Use Value: Maintains uninterrupted service during lightning-induced surges by limiting voltage excursion below 104 V for ASICs and PHY transceivers. |
| Automotive Body Control Module (BCM) | Test & Measurement Equipment Input Protection |
Use Scenario: Protecting 12 V/24 V auxiliary power inputs upgraded to support 85 V battery backup or hybrid vehicle architectures. IC Role / Device Role / Timing Role: Secondary overvoltage clamp after primary fuse and relay, absorbing residual transients missed by bulk protection. Use Value: Extends reliability of microcontroller power domains during cold-crank and jump-start events where voltage may spike to 85 V. | Use Scenario: Shielding analog front-end inputs of multimeters and oscilloscope channels from accidental connection to high-voltage test points. IC Role / Device Role / Timing Role: First-line transient suppressor in input attenuation path, limiting fault voltage before precision op-amps and ADC drivers. Use Value: Preserves measurement accuracy and prevents input stage saturation by clamping 1 kV ESD events to <104 V within <1 ns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85A | Same VRWM (85 V) and VC (104 V), but SMA package (4.5 × 2.7 mm) - 2.8× larger footprint and 2.2 mm height. | Less suitable for ultra-dense layouts; better thermal dissipation in high-repetition surge environments. | Select SMAJ85A only if board space allows larger package and higher steady-state power handling is needed. |
| P6SMB85A | Higher Ppk (600 W vs. 200 W), DO-214AA package (4.5 × 3.2 mm), 2.2 mm height; VRWM = 85 V, VC = 119 V (15% higher). | Used in primary-side AC/DC input stages; clamping voltage marginally exceeds SMF85AT1G's, reducing protection effectiveness for tight-margin ICs. | Choose P6SMB85A for higher-energy surge environments where 119 V clamping is acceptable and board area permits larger package. |
Compared with SMAJ85A and P6SMB85A, the SMF85AT1G delivers identical 85 V standoff and 104 V clamping in a 60% smaller footprint - making it optimal for space-limited secondary-side protection where fast response and low profile are prioritized over ultimate surge energy absorption.
Availability
SMF85AT1G is available at Aetrix Electronics and suitable for industrial power supplies, telecom infrastructure, automotive body control modules, and test equipment requiring stable component supply with RoHS-compliant, Pb-free construction.
Supply support for SMF85AT1G 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, sensor, and connectivity solutions for automotive, industrial, cloud, and IoT applications.
The SMF5.0AT1 Series - including SMF85AT1G - was engineered specifically for compact, high-reliability transient suppression in DC-powered systems where board space, surge immunity, and low leakage are critical design constraints.
FAQ
What is the working peak reverse voltage (VRWM) of the SMF85AT1G?
The SMF85AT1G has a VRWM of 85 V, meaning it remains non-conductive under normal operation up to this DC or continuous peak reverse voltage. This value ensures compatibility with 72–80 V nominal systems like telecom DC feeds and industrial 24 V/48 V upgrades, while providing sufficient margin above operating voltage to prevent leakage-related power loss or false triggering.
How does the SMF85AT1G compare to bidirectional TVS diodes in surge protection?
The SMF85AT1G is unidirectional and optimized for DC rail protection where only positive transients occur - such as in +85 V power distribution. Unlike bidirectional devices, it offers lower capacitance and tighter clamping tolerance in the forward direction, but cannot suppress negative-going surges. For AC or dual-polarity lines, a bidirectional variant like SMBJ85CA would be required instead of the SMF85AT1G.
Is the SMF85AT1G suitable for IEC 61000-4-4 (EFT) compliance testing?
Yes, the SMF85AT1G is rated for 40 A per IEC 61000-4-4 (5/50 ns burst), verified in onsemi's characterization. Its 137 A IPP and 104 V VC ensure reliable clamping during repetitive 40 A bursts without degradation, making it appropriate for front-end protection in industrial controllers and telecom line cards undergoing formal EFT certification using the SMF85AT1G.
What is the thermal resistance of the SMF85AT1G and how does it affect layout?
The SMF85AT1G has a junction-to-cathode thermal resistance (RJcathode) of 26 °C/W. This low value allows efficient heat transfer to the cathode pad, so PCB layout should maximize copper area connected to the cathode terminal - ideally ≥25 mm² of 1 oz copper - to sustain repeated surges without exceeding 150 °C junction temperature, especially in enclosed or high-ambient environments where the SMF85AT1G operates.
Does the SMF85AT1G require derating at elevated ambient temperatures?
Yes, the SMF85AT1G's peak pulse power must be derated above 25 °C ambient, per Figure 4 in the datasheet. At 85 °C, its 200 W rating drops to ~140 W; at 125 °C, it falls to ~80 W. Designers must verify worst-case ambient + self-heating in the final layout to ensure the SMF85AT1G maintains adequate surge margin - particularly in sealed enclosures or stacked PCB assemblies where airflow is limited.
SMF85AT1G 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):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 1.3A
- 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
SMF85AT1G FAQ
1.How can I place an order for SMF85AT1G through Aetrix?
Please submit a Request for Quotation (RFQ) for SMF85AT1G 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 SMF85AT1G reliable?
The price and inventory of SMF85AT1G are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMF85AT1G is usually 5 days.
3.What payment methods are accepted for SMF85AT1G?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMF85AT1G transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMF85AT1G?
SMF85AT1G orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMF85AT1G 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 SMF85AT1G?
For technical support, including SMF85AT1G datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMF85AT1G requirements.
6.How does Aetrix verify that SMF85AT1G is sourced from the original manufacturer or authorized distributors?
All SMF85AT1G 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 SMF85AT1G meets industry standards.
7.What is the process for return or replacement of SMF85AT1G?
All SMF85AT1G units undergo pre-shipment inspection (PSI). If there is an issue with SMF85AT1G, 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 SMF85AT1G part is unused and in its original packaging.
Return procedure for SMF85AT1G:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMF85AT1G 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
-
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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