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onsemi 1SMB75AT3
- Part No.:
- 1SMB75AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB75AT3.pdf
- Description:
- TVS DIODE 75VWM 121VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:3,418
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Product details
Overview
1SMB75AT3 from ON Semiconductor is a unidirectional 600 W peak power TVS diode designed for transient overvoltage protection in DC power rails and signal lines. It features a 75 V working peak reverse voltage (VRWM), 83.3 V nominal breakdown voltage (VBR) at 1 mA, clamps to ≤121 V at 4.9 A peak pulse current (IPP), and delivers sub-1 ns response time. It is widely deployed in industrial power supplies and automotive ECUs where robust ESD and surge immunity are required.
For engineers reviewing the 1SMB75AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include clamping voltage margin relative to system operating voltage, 600 W 1 ms surge rating compliance, UL 497B certification for isolated loop protection, and SMB package thermal performance under repeated transients.
Technical Context
The 1SMB75AT3 operates as a unidirectional Zener-based transient voltage suppressor, leveraging avalanche breakdown to clamp fast-rising surges. Its electrical behavior is defined by three critical voltage thresholds: VRWM = 75 V (maximum continuous reverse voltage), VBR = 83.3 V (breakdown at 1 mA), and VC = 121 V (clamping at IPP = 4.9 A).
It exhibits low leakage (<5.0 µA @ VRWM), high ESD tolerance (>16 kV HBM), and junction capacitance of 245 pF at 0 V bias. Thermal design relies on its 226 °C/W junction-to-ambient resistance and 40 °C/W junction-to-lead resistance, with maximum soldering temperature rated at 260 °C for 10 seconds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 75 V - Maximum continuous reverse operating voltage; must exceed system DC rail voltage to avoid leakage conduction. |
| VBR @ IT = 1 mA | 83.3 V (nominal) - Avalanche breakdown initiates here; ensures predictable turn-on before damaging overvoltage occurs. |
| VC @ IPP = 4.9 A | 121 V - Clamped voltage during 1 ms 600 W surge; defines worst-case stress on protected downstream circuitry. |
| Peak Pulse Power | 600 W @ 1 ms - Sustains high-energy transients per IEC 61000-4-5 Level 4 without failure. |
| Junction Capacitance | 245 pF @ 0 V - Impacts high-frequency signal integrity; suitable for <10 MHz analog/power line protection. |
| ESD Rating | Class 3 (>16 kV HBM) - Meets stringent electrostatic discharge immunity requirements for end-equipment certification. |
| UL Recognition | UL 497B QVGQ2 - Certified for use in isolated loop circuits, including telecom and industrial fieldbus interfaces. |
Pinout & Package
Package: SMB (Case 403A), surface-mount, void-free thermosetting plastic with modified L-bend leads and cathode polarity band. Dimensions: 4.06–4.60 mm (E), 3.30–3.95 mm (D), 1.90–2.45 mm (A), 0.76–1.60 mm (L).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during forward conduction | Connected to lower-potential side (e.g., ground or return path); enables unidirectional clamping from cathode to anode. |
| Cathode | Current exit terminal during reverse avalanche | Connected to protected line (e.g., +75 V rail); conducts surge current to ground when voltage exceeds VRWM. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power | Withstands 1 ms surges up to 4.9 A without degradation-meets IEC 61000-4-5 surge immunity standards. |
| Sub-1 ns response time | Clamps transients before downstream ICs experience overvoltage stress-critical for protecting sensitive microcontrollers and sensors. |
| UL 497B recognition | Validated for isolated loop circuit protection in telecom and industrial control systems-reduces safety certification effort. |
| Pb-free (G suffix) packaging | Complies with RoHS Directive 2011/65/EU and JEDEC J-STD-020 moisture sensitivity level (MSL) 1 handling. |
| Low zener impedance | Ensures stable clamping across temperature and aging-maintains VC ≤121 V over full −65°C to +150°C operating range. |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module (BCM) |
|---|---|
|
Use Scenario: Protects 24 V DC input stage of programmable logic controllers against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VIN and GND, clamping transients before they reach DC-DC converters and MCU power rails. Use Value: Limits voltage excursion to ≤121 V during 100 A/100 ms load dump events-prevents latch-up and permanent damage to 3.3 V/5 V logic. |
Use Scenario: Shields LIN bus transceivers and sensor inputs in BCMs from battery line transients and ESD events. IC Role / Device Role / Timing Role: Cathode tied to LIN data line, anode to chassis ground; responds within <1 ns to suppress ESD spikes per ISO 10605. Use Value: Maintains signal integrity below 12 V threshold while surviving >16 kV contact discharge-ensures reliable communication during vehicle assembly and service. |
| Medical Equipment Power Input | Telecom Remote Terminal Unit (RTU) |
|
Use Scenario: Guards AC/DC adapter outputs feeding patient-monitoring front-end analog circuitry against mains-borne surges. IC Role / Device Role / Timing Role: Mounted directly at power entry point, shunting energy to earth ground before reaching precision ADCs and amplifiers. Use Value: Delivers 245 pF junction capacitance and <5 µA leakage at 75 V-minimizes noise coupling and offset drift in µV-level biopotential measurements. |
Use Scenario: Protects RS-485 interface lines in outdoor RTUs exposed to lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Paired with series current-limiting resistors and common-mode chokes; clamps differential and common-mode transients simultaneously. Use Value: UL 497B certification confirms suitability for isolated data loops-enables single-device compliance with TIA-485-A and IEC 61000-4-5 Level 4 requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ75A | Same VRWM (75 V), identical SMB package, but higher IPP = 5.0 A and slightly lower VC = 120 V; RoHS-compliant but not UL 497B recognized. | Lacks UL 497B certification-unsuitable for isolated loop telecom or medical applications requiring safety agency approval. | Select SMBJ75A only when UL recognition is not mandated and tighter clamping margin is prioritized over certification. |
| 1.5SMC75A | Higher peak power (1500 W), DO-214AB package (larger footprint), VRWM = 75 V, VC = 121 V at 12.3 A; no UL 497B listing. | Requires PCB layout change due to larger case size; suited for higher-energy surges but incompatible with space-constrained SMB footprints. | Choose 1.5SMC75A only if system-level surge testing exceeds 600 W and board area permits DO-214AB mounting. |
Compared with SMBJ75A and 1.5SMC75A, the 1SMB75AT3 uniquely combines UL 497B certification, SMB footprint compatibility, and verified 600 W surge capability-making it the preferred choice for safety-critical, space-constrained industrial and automotive designs requiring regulatory compliance.
Availability
1SMB75AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and medical equipment requiring stable component supply with full traceability and long-term lifecycle support.
Supply support for 1SMB75AT3 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
ON Semiconductor (now onsemi) is a global semiconductor supplier specializing in energy-efficient power management, analog, sensing, and connectivity solutions for automotive, industrial, and cloud power applications.
The 1SMB75AT3 belongs to the SMB series of unidirectional TVS diodes engineered for high-reliability transient suppression in harsh environments-designed specifically for robustness in automotive electronics, industrial controls, and certified medical devices.
FAQ
What is the maximum clamping voltage of the 1SMB75AT3 under surge conditions?
The 1SMB75AT3 clamps to a maximum of 121 V when subjected to its rated peak pulse current of 4.9 A (1 ms exponential waveform). This value is specified as VC in the Electrical Characteristics table and represents the worst-case voltage seen by protected circuitry during a 600 W transient event. The 1SMB75AT3 maintains this clamping performance across its full operating temperature range of −65°C to +150°C.
Is the 1SMB75AT3 certified for safety-critical applications?
Yes, the 1SMB75AT3 carries UL 497B recognition (File #E210057, Category QVGQ2) for isolated loop circuit protection. This certification validates its performance in surge endurance, dielectric withstand, and flammability testing-making it suitable for safety-related subsystems in industrial automation, telecom infrastructure, and Class II medical equipment where regulatory compliance is mandatory. The 1SMB75AT3 is explicitly listed in UL's database for protector applications.
Does the 1SMB75AT3 have lead-free construction?
Yes, the "G" suffix in 1SMB75AT3 indicates Pb-free (lead-free) packaging compliant with RoHS Directive 2011/65/EU. The device uses matte tin-plated leads and meets JEDEC J-STD-020 moisture sensitivity level (MSL) 1 requirements, allowing unlimited floor life and reflow soldering at peak temperatures up to 260°C for 10 seconds. All 1SMB75AT3 units supplied by Aetrix Electronics are RoHS-compliant and fully traceable.
How does the 1SMB75AT3 compare to bidirectional TVS diodes?
The 1SMB75AT3 is unidirectional and optimized for DC line protection where polarity is fixed-such as +75 V power rails or grounded-signal interfaces. Unlike bidirectional variants (e.g., 1SMB75CAT3), it blocks reverse current until avalanche occurs, offering lower leakage (<5 µA @ 75 V) and sharper turn-on. Bidirectional types are reserved for AC or floating lines like Ethernet or USB D+/D−, where voltage swings above and below ground require symmetrical clamping.
What is the thermal resistance profile of the 1SMB75AT3?
The 1SMB75AT3 has a junction-to-lead thermal resistance (RJL) of 40 °C/W and a junction-to-ambient resistance (RJA) of 226 °C/W under standard FR-4 board conditions (minimum recommended footprint). These values define its ability to dissipate heat during repetitive surge events: at 75°C lead temperature, its DC power dissipation derates to 3.0 W, while at 25°C ambient, it supports 0.55 W continuously. Proper copper pour and thermal vias are essential to maintain reliability under sustained stress.
1SMB75AT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 75V
- Voltage - Breakdown (Min):
- 83.3V
- Voltage - Clamping (Max) @ Ipp:
- 121V
- Current - Peak Pulse (10/1000µs):
- 4.9A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 245pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB75AT3 FAQ
1.How can I place an order for 1SMB75AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB75AT3 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 1SMB75AT3 reliable?
The price and inventory of 1SMB75AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB75AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB75AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB75AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB75AT3?
1SMB75AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB75AT3 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 1SMB75AT3?
For technical support, including 1SMB75AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB75AT3 requirements.
6.How does Aetrix verify that 1SMB75AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB75AT3 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 1SMB75AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB75AT3?
All 1SMB75AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB75AT3, 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 1SMB75AT3 part is unused and in its original packaging.
Return procedure for 1SMB75AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB75AT3 Tags
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