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onsemi 1SMB30AT3
- Part No.:
- 1SMB30AT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB30AT3.pdf
- Description:
- TVS DIODE 30VWM 48.4VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:3,999
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Product details
Overview
1SMB30AT3 from ON Semiconductor is a unidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 30 V working peak reverse voltage (VRWM), 48.4 V clamping voltage at 12.4 A peak pulse current, and sub-1 ns response time - enabling robust surge suppression in power supply inputs, automotive ECUs, and industrial I/O interfaces.
For engineers reviewing the 1SMB30AT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system DC bus voltage, VC margin below IC absolute maximum ratings, UL 497B certification for isolated loop protection, and SMB package compatibility with high-density PCB layouts.
Technical Context
The 1SMB30AT3 operates as a Zener-based avalanche clamp, triggered when transient voltage exceeds its 33.3 V minimum breakdown voltage (VBR) at 1 mA test current. Its low zener impedance and fast junction response ensure stable clamping under 10/1000 µs surge waveforms per IEC 61000-4-5.
Designed for surface-mount placement adjacent to protected circuitry, it leverages the SMB (Case 403A) thermoset plastic package with modified L-bend leads for enhanced solder joint reliability and thermal dissipation. Polarity is marked by a cathode band, requiring correct orientation in series with the protected line.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Peak Reverse Voltage (VRWM) | 30 V - Maximum continuous DC or peak AC voltage the device blocks without clamping; must be ≥ circuit operating voltage. |
| Clamping Voltage (VC) @ IPP | 48.4 V @ 12.4 A - Maximum voltage seen by protected load during 1 ms 600 W surge; defines safe margin below downstream IC limits. |
| Peak Pulse Power (PPK) | 600 W @ 1 ms - Surge energy handling capability per non-repetitive 10/1000 µs waveform; validated per Figure 2 in datasheet. |
| Breakdown Voltage (VBR) | 33.3–36.8 V @ 1 mA - Zener avalanche initiation range; ensures reliable turn-on before VC is reached. |
| Leakage Current (IR) | <5.0 µA @ 30 V - Negligible standby power loss and signal integrity impact in high-impedance circuits. |
| Response Time | <1.0 ns - Enables suppression of fast transients (e.g., ESD, relay bounce) before damage occurs to downstream components. |
| UL Recognition | UL 497B QVGQ2 - Certified for isolated loop circuit protection; passes strike voltage, endurance, dielectric withstand, and discharge testing. |
Pinout & Package
Package: SMB (Case 403A), surface-mount, void-free thermosetting plastic housing with 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 during forward conduction; grounded or connected to low-side reference in unidirectional configuration | Provides return path for surge current; must connect to lowest potential node in protected circuit. |
| Cathode | Protected line connection; clamps to anode when transient exceeds VRWM | Connected to the line being safeguarded (e.g., +12 V rail); polarity band identifies this terminal. |
Key Features
| Feature | Design Value |
|---|---|
| 600 W peak pulse power rating | Handles IEC 61000-4-5 Level 4 surges (4 kV line-to-earth) without degradation when properly mounted on FR-4 with recommended footprint. |
| ESD rating >16 kV HBM | Withstands human-body-model electrostatic discharge events common in handling and assembly, reducing field failure risk. |
| Low clamping ratio (VC/VBR ≈ 1.45) | Minimizes overvoltage stress on protected ICs - critical for 3.3 V or 5 V logic interfacing with higher-voltage domains. |
| Pb-free (RoHS-compliant) packaging | Meets global environmental regulations; compatible with standard lead-free reflow profiles (260°C/10 s max). |
| UL 497B recognition | Validated for use in safety-critical isolated loop applications (e.g., 4–20 mA sensor transmitters), not just generic surge suppression. |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) I/O |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controller (PLC) power supply exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed across input terminals to clamp surges before they reach upstream rectifier and bulk capacitor. Use Value: Limits transient voltage to ≤48.4 V, preventing overstress of 63 V-rated input capacitors and ensuring uninterrupted operation during ISO 16750-2 load dump events. |
Use Scenario: LIN bus or switched 12 V sensor lines in BCM subjected to battery reversal and jump-start transients. IC Role / Device Role / Timing Role: Line-side TVS on each protected I/O pin, oriented to block reverse polarity while clamping positive spikes. Use Value: Maintains <5 µA leakage at 12 V nominal, avoiding false wake-up in low-power sleep modes while suppressing 100 V/10 ms transients per ISO 7637-2. |
| Medical Equipment Isolated Signal Interface | Telecom DSL Line Card Surge Protection |
Use Scenario: 4–20 mA current loop interface between patient monitor and external analyzer, requiring UL 497B compliance for isolation barrier integrity. IC Role / Device Role / Timing Role: Primary overvoltage clamp on secondary side of isolated analog front-end, referenced to local ground. Use Value: UL 497B certification validates performance under sustained overvoltage and repeated surge conditions - essential for Class II medical device approval. |
Use Scenario: Tip/ring lines of ADSL/VDSL line card exposed to lightning-induced surges on outside plant wiring. IC Role / Device Role / Timing Role: First-stage unidirectional suppressor before gas discharge tube (GDT) and series impedance, shunting fast-rising edges. Use Value: Sub-1 ns response captures initial surge edge before GDT fires, reducing let-through energy and extending GDT lifetime in hybrid protection schemes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ30A | Same VRWM (30 V) and VC (48.4 V), but rated for 600 W with tighter VBR tolerance (33.3–36.8 V vs. 33.3–36.8 V); identical SMB package. | No functional difference in clamping behavior; validated for same IEC/ISO standards. | Drop-in replacement with identical electrical specs and footprint; preferred where second-source assurance is required. |
| 1.5SMC30A | Higher package thermal resistance (RJA = 226 °C/W vs. 226 °C/W), same VRWM/VC, but larger SMC package (7.1 × 6.2 mm vs. 4.6 × 3.95 mm). | Requires PCB layout change; better suited for higher ambient temperature environments due to larger copper pad area. | Select only if board space allows SMC footprint and thermal derating at >75°C ambient is critical. |
Compared with SMBJ30A, the 1SMB30AT3 offers identical surge performance in a cost-optimized Surmetic SMB package; versus 1.5SMC30A, it trades thermal margin for compactness - making it optimal for space-constrained 24 V industrial controls and automotive modules.
Availability
1SMB30AT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, and medical isolated interfaces requiring stable component supply, RoHS compliance, and UL 497B certification.
Supply support for 1SMB30AT3 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 manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and cloud power applications.
The 1SMB30AT3 belongs to the SMB series of unidirectional TVS diodes engineered for high-energy transient suppression in harsh environments - emphasizing reliability, UL certification, and cost-effective surface-mount integration.
FAQ
What is the maximum clamping voltage of the 1SMB30AT3 under surge conditions?
The 1SMB30AT3 has a maximum clamping voltage (VC) of 48.4 V when subjected to its rated peak pulse current of 12.4 A (10/1000 µs waveform). This value is measured per the test conditions defined in the ON Semiconductor datasheet and represents the highest voltage that will appear across the protected circuit during a 600 W transient event. Designers must verify that this clamping level remains safely below the absolute maximum voltage rating of downstream components.
Is the 1SMB30AT3 suitable for bidirectional transient protection?
No, the 1SMB30AT3 is a unidirectional TVS diode and is not suitable for bidirectional protection. It conducts only during positive transients on the cathode relative to anode and blocks reverse voltage up to 30 V. For AC or bipolar surge environments (e.g., data lines, RS-485), a bidirectional variant such as 1SMB30AT3-B or SMBJ30CA must be used instead. The "A" suffix in 1SMB30AT3 explicitly denotes unidirectional construction.
Does the 1SMB30AT3 meet UL 497B requirements for isolated loop protection?
Yes, the entire 1SMB5.0AT3 series, including the 1SMB30AT3, carries UL 497B recognition under file #E210057 in the QVGQ2 protector category. It has passed all required tests - including strike voltage breakdown, endurance conditioning, dielectric voltage-withstand, and discharge testing - confirming suitability for use in safety-isolated circuits such as 4–20 mA loops and medical signal interfaces.
What is the thermal resistance and derating behavior of the 1SMB30AT3?
The 1SMB30AT3 has a junction-to-ambient thermal resistance (RJA) of 226 °C/W on a standard FR-4 board with ON Semiconductor's recommended footprint. Its DC power dissipation is rated at 0.55 W at 25°C ambient, derating linearly by 4.4 mW/°C above that temperature. At 75°C ambient, the derated PD drops to 0.33 W - a critical consideration for high-density or enclosed industrial designs where airflow is limited.
Can the 1SMB30AT3 be used in automotive applications compliant with ISO 7637-2?
Yes, the 1SMB30AT3 is widely deployed in automotive body electronics for ISO 7637-2 Pulse 1 (inductive load dump) and Pulse 2a (sudden load interruption) suppression. Its 30 V VRWM aligns with 24 V system nominal voltages, and its 48.4 V clamping voltage provides sufficient margin below typical 60 V automotive IC limits. Layout best practices - short traces, direct grounding, and proximity to protected pins - are essential to achieve full spec compliance.
1SMB30AT3 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):
- 30V
- Voltage - Breakdown (Min):
- 33.3V
- Voltage - Clamping (Max) @ Ipp:
- 48.4V
- Current - Peak Pulse (10/1000µs):
- 12.4A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 555pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB30AT3 FAQ
1.How can I place an order for 1SMB30AT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB30AT3 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 1SMB30AT3 reliable?
The price and inventory of 1SMB30AT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB30AT3 is usually 5 days.
3.What payment methods are accepted for 1SMB30AT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB30AT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB30AT3?
1SMB30AT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB30AT3 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 1SMB30AT3?
For technical support, including 1SMB30AT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB30AT3 requirements.
6.How does Aetrix verify that 1SMB30AT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB30AT3 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 1SMB30AT3 meets industry standards.
7.What is the process for return or replacement of 1SMB30AT3?
All 1SMB30AT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB30AT3, 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 1SMB30AT3 part is unused and in its original packaging.
Return procedure for 1SMB30AT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB30AT3 Tags
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