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onsemi 1SMB45CAT3
- Part No.:
- 1SMB45CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB45CAT3.pdf
- Description:
- TVS DIODE 45VWM 72.2VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:2,798
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Product details
Overview
1SMB45CAT3 from ON Semiconductor is a bidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 45 V working peak reverse voltage (VRWM), 55.3 V clamping voltage at 8.3 A peak pulse current, and sub-1 ns response time. Used in power supplies, industrial controls, and automotive ECUs to absorb ESD and lightning-induced surges.
For engineers reviewing the 1SMB45CAT3 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 thermal performance under repetitive surge conditions.
Technical Context
The 1SMB45CAT3 operates as a bidirectional Zener-based TVS, leveraging avalanche breakdown to clamp transients symmetrically across both polarities. Its low zener impedance (<1 Ω typical) and fast turn-on ensure minimal overshoot during <1 ns events, critical for protecting high-speed interfaces and microcontroller I/Os.
It is rated for 600 W non-repetitive peak pulse power (10/1000 µs waveform), with thermal derating above 75°C lead temperature. The device meets Class 3 HBM ESD (>16 kV) and UL 497B for isolated loop circuit protection - confirming suitability for telecom and industrial field wiring.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 45 V - Maximum continuous reverse operating voltage; must be ≥ system DC rail to avoid leakage conduction during normal operation. |
| VC @ IPP | 72.2 V @ 8.3 A - Clamped voltage during 10/1000 µs surge; defines worst-case stress on downstream components. |
| PPK | 600 W - Peak pulse power handling capability; validates robustness against lightning or inductive switch-off transients. |
| Response Time | < 1 ns - Enables protection of fast-edge digital signals and switching power supply feedback paths without signal distortion. |
| ESD Rating | Class 3 (>16 kV HBM) - Confirms immunity to common human-body electrostatic discharge events in assembly and field use. |
| UL Recognition | UL 497B (QVGV2) - Certified for use in isolated communication loops, including RS-485, CAN, and analog sensor interfaces. |
| IR @ VRWM | < 5 µA - Low leakage ensures negligible standby current draw in battery-powered or high-impedance sensing circuits. |
Pinout & Package
Package: SMB (DO-214AA), surface-mount, void-free thermosetting plastic case (Case 403A). Dimensions: 4.06 × 3.30 × 2.11 mm (L × W × H); modified L-bend leads for enhanced pad adhesion.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Marked Band) | Transient Current Sink (Bidirectional) | Acts as cathode during positive transients and anode during negative transients; polarity band not indicated per spec - device is symmetric. |
| Anode | Transient Current Source (Bidirectional) | Completes low-impedance path during reverse-polarity surges; identical electrical behavior to cathode due to bidirectional Zener structure. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional Clamping | Protects AC-coupled lines and differential buses (e.g., RS-485, CAN) without polarity sensitivity or external diode pairing. |
| 600 W Surge Rating | Withstands IEC 61000-4-5 Level 4 (4 kV line-to-earth) surges when properly mounted with short traces and ground plane coupling. |
| UL 497B Certification | Validated for use in safety-critical isolated loop applications - eliminates need for separate certification testing by end-equipment OEMs. |
| Sub-1 ns Response | Minimizes voltage overshoot before clamping engages, preserving integrity of 3.3 V/5 V logic and ADC reference inputs. |
| Low Leakage <5 µA | Enables use in high-impedance sensor front-ends and battery-backed real-time clocks without measurable bias error or drain. |
Applications
| Industrial Power Supplies | Automotive Body Control Modules |
|---|---|
|
Use Scenario: Input stage of 24 V DC-DC converter subjected to load dump (ISO 7637-2 Pulse 5a) and jump-start transients. IC Role / Device Role: Primary overvoltage clamp placed across input filter capacitor, shunting surge energy to ground. Use Value: Limits input rail to ≤72.2 V during 8.3 A surge, preventing damage to upstream MOSFETs and controller ICs rated for 80 V max. |
Use Scenario: LIN bus transceiver protection in door module exposed to ESD and cable discharge events. IC Role / Device Role: Bidirectional TVS connected between LIN line and chassis ground, suppressing ±15 kV contact ESD per ISO 10605. Use Value: Maintains signal integrity below 1 Mbps while limiting transceiver pin stress to <72.2 V - within ABS MAX rating of TJA1020. |
| Medical Sensor Interfaces | Telecom Line Cards |
|
Use Scenario: Protection of analog front-end (AFE) inputs in portable ECG monitor connected to patient electrodes. IC Role / Device Role: Low-leakage TVS on differential input path, guarding against defibrillator-induced transients (IEC 60601-1-2). Use Value: Adds <5 µA leakage at 45 V, avoiding baseline shift in µV-level biopotential measurements while clamping >1 kV surges. |
Use Scenario: Overvoltage protection on POTS line interface of VoIP gateway exposed to lightning-induced surges. IC Role / Device Role: UL 497B-certified TVS on tip/ring lines, integrated into hybrid transformer secondary side. Use Value: Meets GR-1089-CORE requirements for primary protection; clamps induced surges to <72.2 V before reaching SLIC and codec ICs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ45CA | Same VRWM (45 V), identical SMB package, but lower 400 W peak power rating and no UL 497B recognition. | Lacks UL certification for isolated loop use; suitable only for non-safety-critical board-level protection. | Select SMBJ45CA only if UL compliance is unnecessary and surge energy is limited to ≤400 W. |
| 1.5SMC47CA | Higher 1500 W rating and same 45 V VRWM, but larger SMC (DO-214AB) package (7.11 × 6.22 mm) requiring PCB layout change. | Offers greater surge margin for harsh environments (e.g., railway traction control), but incompatible with space-constrained SMB footprints. | Choose 1.5SMC47CA when higher energy handling is required and board area permits larger SMC footprint. |
Compared with SMBJ45CA and 1.5SMC47CA, the 1SMB45CAT3 uniquely balances 600 W surge capacity, UL 497B certification, and compact SMB footprint - making it optimal for certified industrial and telecom equipment where space, safety, and reliability are jointly constrained.
Availability
1SMB45CAT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, and medical sensor interfaces requiring stable component supply and long-term lifecycle support.
Supply support for 1SMB45CAT3 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 is a global semiconductor manufacturer specializing in power management, analog, sensors, and discrete devices for automotive, industrial, and communications markets.
The 1SMB45CAT3 belongs to the SMB-series transient voltage suppressors - engineered for high-energy surge clamping in space-constrained, safety-certified applications such as industrial automation and telecom infrastructure.
FAQ
What is the clamping voltage of the 1SMB45CAT3 at its rated peak pulse current?
The 1SMB45CAT3 has a maximum clamping voltage (VC) of 72.2 V at 8.3 A peak pulse current (IPP), measured using the standard 10/1000 µs double-exponential waveform. This value defines the upper voltage limit imposed on protected circuitry during a full-rated surge event and must be verified against downstream IC absolute maximum ratings in the final design.
Is the 1SMB45CAT3 unidirectional or bidirectional, and how does that affect its placement?
The 1SMB45CAT3 is a bidirectional TVS diode, meaning it clamps transients of either polarity symmetrically. It requires no orientation during placement - unlike unidirectional devices, there is no designated anode/cathode functional distinction. This simplifies layout on AC-coupled or differential signal lines such as RS-485 or CAN, where polarity reversal is inherent.
Does the 1SMB45CAT3 meet UL safety standards, and which ones?
Yes, the 1SMB45CAT3 is UL Recognized under UL 497B (File #116110, Category QVGV2) for protectors used in isolated loop circuits. This certification covers validation of strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge performance - confirming suitability for telecom, industrial fieldbus, and medical isolation barrier applications.
What is the maximum operating temperature range for the 1SMB45CAT3?
The 1SMB45CAT3 supports an operating and storage temperature range of –65 °C to +150 °C. Its junction-to-lead thermal resistance is 40 °C/W, and derating begins above 75 °C lead temperature - critical for designs operating in engine compartments or enclosed industrial enclosures where ambient temperatures exceed 75 °C.
How does the 1SMB45CAT3 compare to the 1SMB43CAT3 in terms of voltage ratings?
The 1SMB45CAT3 has a 45 V working peak reverse voltage (VRWM) and 55.3 V nominal breakdown voltage (VBR), whereas the 1SMB43CAT3 specifies 43 V VRWM and 52.8 V VBR. Both share identical 600 W surge rating and SMB package, but the 1SMB45CAT3 provides tighter margin above 42 V nominal rails (e.g., 24 V systems with 75% tolerance), reducing risk of premature conduction.
1SMB45CAT3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Package/Case:
- DO-214AA, SMB
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 72.2V
- Current - Peak Pulse (10/1000µs):
- 8.3A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 200pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB45CAT3 FAQ
1.How can I place an order for 1SMB45CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB45CAT3 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 1SMB45CAT3 reliable?
The price and inventory of 1SMB45CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB45CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMB45CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB45CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB45CAT3?
1SMB45CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB45CAT3 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 1SMB45CAT3?
For technical support, including 1SMB45CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB45CAT3 requirements.
6.How does Aetrix verify that 1SMB45CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB45CAT3 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 1SMB45CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMB45CAT3?
All 1SMB45CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB45CAT3, 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 1SMB45CAT3 part is unused and in its original packaging.
Return procedure for 1SMB45CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB45CAT3 Tags
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ESD9B5.0ST5G
onsemi
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DESD3V3E1BL-7B
Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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DESD5V0U1BA-7
Diodes Incorporated
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onsemi
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DESD5V0U1BB-7
Diodes Incorporated
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Diodes Incorporated
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PESD2V0Y1BSFYL
Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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