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onsemi 1SMB40CAT3
- Part No.:
- 1SMB40CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB40CAT3.pdf
- Description:
- TVS DIODE 40VWM 64.5VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:6,812
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Product details
Overview
1SMB40CAT3 from ON Semiconductor is a bidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 40 V working peak reverse voltage (VRWM), 49.1 V clamping voltage (VC) at 9.3 A peak pulse current, and sub-1 ns response time-ideal for safeguarding power supplies and communication interfaces against ESD and lightning-induced surges.
For engineers reviewing the 1SMB40CAT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system operating voltage, VC margin relative to IC absolute maximum ratings, UL 497B certification for isolated loop protection, and SMB package thermal performance under repetitive surge conditions.
Technical Context
The 1SMB40CAT3 operates as a bidirectional Zener-based TVS, leveraging avalanche breakdown to clamp transients above its 44.2–49.1 V breakdown range. Its low zener impedance and fast <1 ns turn-on ensure minimal overshoot when placed close to protected circuitry.
It is rated for 600 W non-repetitive peak pulse power (10/1000 µs waveform), with thermal derating starting at 75°C junction temperature. The device meets Class 3 HBM ESD immunity (>16 kV) and UL 497B recognition for isolated loop circuit protection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 40 V - must be ≥ continuous DC or peak AC operating voltage of protected line |
| VBR min/max | 44.2 V / 49.1 V - defines guaranteed avalanche conduction onset window at 1 mA test current |
| VC @ IPP | 64.5 V @ 9.3 A - maximum clamped voltage seen by downstream circuit during 10/1000 µs surge |
| PPK | 600 W @ 1 ms - peak surge energy handling capacity under standardized non-repetitive pulse |
| IR @ VRWM | <5 µA - negligible leakage current ensures no measurable loading on 40 V bias rails |
| Response time | <1 ns - enables effective suppression of fast-rising ESD and switching noise transients |
| ESD rating | Class 3 HBM (>16 kV) - exceeds IEC 61000-4-2 Level 4 for system-level robustness |
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), with modified L-bend leads for enhanced pad adhesion.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (banded end) | Anode/Cathode terminal | Bidirectional operation: both terminals function identically; polarity band is not marked per spec |
| Anode (non-banded end) | Anode/Cathode terminal | No functional distinction - symmetric Zener structure enables equal clamping in either direction |
Key Features
| Feature | Design Value |
|---|---|
| UL 497B Recognition | Validated for isolated loop circuit protection - supports compliance-critical telecom and industrial interface designs |
| Low Clamping Ratio | VC/VRWM = 1.61 - tight ratio minimizes overvoltage stress on downstream ICs without excessive derating |
| High Surge Robustness | Withstands 600 W (10/1000 µs) - suitable for automotive load-dump and industrial surge immunity testing |
| Thermal Performance | RJA = 226 °C/W (FR-4), RJL = 40 °C/W - enables high-power dissipation with minimal PCB copper area |
| ESD Hardness | >16 kV HBM - eliminates need for additional ESD stages in USB, RS-485, and sensor front-ends |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module |
|---|---|
Use Scenario: Protecting 36–42 V DC input rails in programmable logic controllers and motor drives from load dump and inductive kickback. IC Role / Device Role / Timing Role: Bidirectional shunt clamp placed directly across input terminals to limit transient overvoltage before it reaches DC-DC converters and microcontrollers. Use Value: 64.5 V clamping ensures safe operation within 80% of typical 80 V automotive ABS max rating, avoiding damage to 65 V-rated input stages. | Use Scenario: Safeguarding LIN bus transceivers and sensor inputs in door modules and seat control units against battery reversal and jump-start spikes. IC Role / Device Role / Timing Role: Parallel-connected TVS on LIN signal line and VBAT supply rail to absorb ±100 V/50 ms pulses per ISO 7637-2 Pulse 5a. Use Value: Sub-1 ns response and 9.3 A peak current capability meet stringent automotive surge immunity requirements without signal distortion. |
| Medical Equipment Isolated Interfaces | Telecom Line Card Surge Protection |
Use Scenario: Protecting isolated analog front-ends in patient monitoring devices connected to external sensors or accessories. IC Role / Device Role / Timing Role: UL 497B-recognized TVS on secondary-side signal lines to maintain creepage/clearance integrity while suppressing coupling transients. Use Value: UL recognition validates suitability for safety-isolated circuits - eliminates need for separate certification testing of protection scheme. | Use Scenario: Front-end surge protection for Ethernet PHYs and PoE injectors in enterprise switches and base station backhaul cards. IC Role / Device Role / Timing Role: Primary-stage TVS on 48 V DC input and differential data lines to absorb lightning-induced common-mode surges per IEC 61000-4-5. Use Value: 600 W peak power rating supports Level 4 (4 kV line-earth) surge testing without degradation after multiple events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ40CA | Same VRWM (40 V), identical SMB package, but 600 W rating per JEDEC standard; slightly higher VC (64.8 V @ 9.2 A) | JEDEC-compliant footprint and test conditions - preferred where standardized qualification is required | Select SMBJ40CA for designs requiring JEDEC JESD22-A114F alignment or when sourcing from distributors emphasizing JEDEC nomenclature |
| P6SMB40CA | Same electrical specs and SMB package, but manufactured by STMicroelectronics; identical VRWM, VBR, and VC values per datasheet | No functional or layout difference - drop-in alternative with alternate supply chain and lifecycle status | Choose P6SMB40CA to mitigate single-source risk while maintaining identical board-level performance and thermal behavior |
Compared with SMBJ40CA and P6SMB40CA, the 1SMB40CAT3 offers identical clamping performance and UL 497B recognition, but differs in marking format and tape-and-reel packaging (T3 = 13″ reel); all three support the same PCB footprint and thermal design rules.
Availability
1SMB40CAT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive ECUs, medical isolation barriers, and telecom line cards requiring stable component supply across multi-year production cycles.
Supply support for 1SMB40CAT3 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 part of onsemi) is a global semiconductor supplier specializing in energy-efficient power, analog, sensor, and connectivity solutions for automotive, industrial, cloud, and medical markets.
The 1SMB40CAT3 belongs to the SMB-series transient voltage suppressor family, engineered specifically for high-energy surge protection in space-constrained surface-mount applications where reliability, UL certification, and fast response are critical.
FAQ
What is the clamping voltage of the 1SMB40CAT3 under maximum surge conditions?
The 1SMB40CAT3 has a maximum clamping voltage (VC) of 64.5 V when subjected to its rated peak pulse current of 9.3 A using the standard 10/1000 µs waveform. This value is measured at TA = 25°C and represents the upper limit of voltage seen by protected circuitry during worst-case transient events. Designers must verify that this clamping level remains below the absolute maximum ratings of downstream components in the 1SMB40CAT3-protected system.
Does the 1SMB40CAT3 require polarity-aware PCB layout?
No - the 1SMB40CAT3 is a bidirectional TVS diode with symmetric Zener characteristics, meaning both terminals perform identically regardless of voltage polarity. Its datasheet explicitly states "Polarity band will not be indicated," and the device functions identically whether installed in either orientation. This simplifies layout and eliminates orientation-related assembly errors in high-volume manufacturing of boards using the 1SMB40CAT3.
Is the 1SMB40CAT3 certified for safety-critical isolation applications?
Yes - the 1SMB40CAT3 carries UL 497B recognition (File #116110, QVGV2 category) specifically for isolated loop circuit protection. This certification validates its performance in telecom, medical, and industrial systems requiring reinforced insulation and verified surge withstand capability. Unlike generic TVS diodes, the 1SMB40CAT3's UL listing covers dielectric withstand, endurance conditioning, and strike voltage breakdown - making it suitable for safety-critical 1SMB40CAT3 deployments without additional qualification.
How does thermal derating affect the 1SMB40CAT3's surge capability in enclosed environments?
The 1SMB40CAT3's peak pulse power rating of 600 W applies only at TL = 25°C. Above 75°C lead temperature, its DC power dissipation derates at 25 mW/°C, and ambient-temperature derating follows RJA = 226 °C/W on FR-4. In enclosed enclosures with limited airflow, sustained high ambient temperatures reduce effective surge margin - designers must use the Figure 3 derating curve from the 1SMB40CAT3 datasheet to adjust allowable pulse energy based on actual board temperature measurements.
Can the 1SMB40CAT3 replace older 1.5KE40CA through-hole TVS diodes?
The 1SMB40CAT3 is not a direct drop-in replacement for through-hole 1.5KE40CA due to package (SMB vs. DO-15), thermal path (surface-mount vs. leaded), and surge waveform differences (10/1000 µs vs. 8/20 µs). While both have similar VRWM and VC, the 1SMB40CAT3's lower RJA and optimized layout proximity enable superior high-frequency transient suppression - but PCB redesign is required. Use the 1SMB40CAT3 only in new SMT designs or after validating thermal and mechanical compatibility in the target 1SMB40CAT3 application.
1SMB40CAT3 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):
- 40V
- Voltage - Breakdown (Min):
- 44.4V
- Voltage - Clamping (Max) @ Ipp:
- 64.5V
- Current - Peak Pulse (10/1000µs):
- 9.3A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 220pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB40CAT3 FAQ
1.How can I place an order for 1SMB40CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB40CAT3 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 1SMB40CAT3 reliable?
The price and inventory of 1SMB40CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB40CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMB40CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB40CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB40CAT3?
1SMB40CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB40CAT3 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 1SMB40CAT3?
For technical support, including 1SMB40CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB40CAT3 requirements.
6.How does Aetrix verify that 1SMB40CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB40CAT3 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 1SMB40CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMB40CAT3?
All 1SMB40CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB40CAT3, 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 1SMB40CAT3 part is unused and in its original packaging.
Return procedure for 1SMB40CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB40CAT3 Tags
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ESD9B5.0ST5G
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DESD3V3E1BL-7B
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