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onsemi 1SMB43CAT3
- Part No.:
- 1SMB43CAT3
- Manufacturer:
- onsemi
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
1SMB43CAT3.pdf
- Description:
- TVS DIODE 43VWM 69.4VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:2,800
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Product details
Overview
1SMB43CAT3 from ON Semiconductor is a bidirectional 600 W transient voltage suppressor (TVS) diode designed for parallel overvoltage protection of sensitive electronics. It features a 43 V working peak reverse voltage (VRWM), 52.8 V clamping voltage (VC) at 8.6 A peak pulse current, and sub-1 ns response time - deployed in power supply input stages, automotive ECUs, and industrial I/O interfaces to absorb lightning-induced surges and ESD events.
For engineers reviewing the 1SMB43CAT3 datasheet, pinout, applications, or equivalent options, key selection criteria include VRWM ≥ system DC bus 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 1SMB43CAT3 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 rise-time surges, while its 600 W peak power rating (10/1000 µs waveform) supports robust protection against IEC 61000-4-5 Level 4 surges.
Thermal design relies on junction-to-lead resistance (RJL = 40 °C/W) and derating above 75°C, with FR-4 board mounting using the Case 403A footprint. The device meets Class 3 HBM ESD (>16 kV) and UL 497B recognition for isolated loop circuit protection - critical for telecom line cards and medical sensor interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 43 V - must be ≥ continuous operating voltage of protected circuit (e.g., 36 V DC bus) |
| VBR @ IT=1 mA | 47.8–50.32 V - ensures reliable avalanche initiation without premature conduction |
| VC @ IPP=8.6 A | 69.4 V - maximum clamped voltage seen by downstream ICs during full-rated surge |
| IPP | 8.6 A - peak pulse current capability under 10/1000 µs waveform per IEC 61000-4-5 |
| Leakage @ VRWM | <5 µA - negligible standby power loss in high-impedance monitoring circuits |
| Response Time | <1 ns - limits voltage overshoot before clamping engages during fast-rising transients |
| UL Recognition | UL 497B (QVGV2) - certified for use in safety-critical isolated loop protection applications |
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 (marked band side) | Transient current sink (bidirectional) | Both terminals conduct equally during positive/negative surges - no polarity marking required |
| Anode (unmarked side) | Transient current sink (bidirectional) | Symmetric Zener structure enables identical clamping in either direction - simplifies PCB layout |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC lines or floating DC rails without polarity concerns |
| 600 W peak power (1 ms) | Withstands IEC 61000-4-5 Combination Wave (1.2/50 µs voltage + 8/20 µs current) surges up to Level 4 |
| UL 497B recognition | Validated for use in telecom and industrial isolated loop protectors - exceeds basic flammability requirements |
| Class 3 HBM ESD rating | Survives >16 kV human-body-model discharges - suitable for unshielded front-panel interfaces |
| Low clamping ratio (VC/VBR ≈ 1.38) | Minimizes stress on downstream components by limiting overvoltage margin to ~38% above breakdown |
Applications
| Industrial Power Supply Input Protection | Automotive Body Control Module (BCM) I/O |
|---|---|
|
Use Scenario: Protecting 48 V DC input stage of programmable logic controller (PLC) power supply against load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Parallel-connected TVS that clamps transients before they reach upstream rectifier and downstream DC/DC controller. Use Value: 69.4 V clamping voltage ensures microcontroller and gate drivers remain below 70 V absolute max rating during 100 V/50 ms load dump events. |
Use Scenario: Safeguarding LIN bus transceiver pins in BCM against battery reverse connection and jump-start surges. IC Role / Device Role / Timing Role: Bidirectional shunt element placed directly at connector entry point to divert surge energy away from transceiver ESD structures. Use Value: Sub-1 ns response prevents >100 V overshoot from reaching transceiver inputs during 100 ns rise-time transients per ISO 16750-2. |
| Medical Sensor Signal Conditioning | Telecom DSL Line Interface |
|
Use Scenario: Protecting analog front-end of patient-monitoring ECG amplifier from defibrillator-induced transients. IC Role / Device Role / Timing Role: Low-leakage (≤5 µA) TVS placed across differential input pair to suppress common-mode surges without degrading signal integrity. Use Value: 43 V VRWM matches ±24 V op-amp supply rails, enabling clamping before amplifier saturation or latch-up occurs. |
Use Scenario: Shielding ADSL line driver/receiver from lightning-induced surges on twisted-pair copper lines. IC Role / Device Role / Timing Role: UL 497B-certified bidirectional suppressor integrated into hybrid transformer interface to meet Telcordia GR-1089-CORE requirements. Use Value: UL recognition validates compliance for central office and customer premises equipment - eliminating need for additional certification testing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ43CA | Same VRWM (43 V) and VC (69.4 V), but rated for 600 W with tighter VBR tolerance (47.8–49.1 V vs. 47.8–50.32 V); slightly lower IPP (8.6 A vs. 8.6 A, identical) | Preferred for designs requiring tighter breakdown consistency across temperature; same SMB package and footprint | Select SMBJ43CA when VBR uniformity across production lots is critical for predictable clamping threshold |
| 1.5SMC43CA | Higher peak power (1500 W), larger SMC package (DO-214AB), higher thermal resistance (RJA = 1.1 °C/W vs. 226 °C/W for SMB), same VRWM/VC specs | Suitable for high-energy surge environments (e.g., outdoor telecom cabinets) where PCB space allows larger footprint | Choose 1.5SMC43CA only if system-level surge testing requires >600 W capability and SMC mounting is feasible |
Compared with SMBJ43CA and 1.5SMC43CA, the 1SMB43CAT3 offers optimal balance of compact SMB footprint, UL 497B certification, and verified 600 W surge handling - making it ideal for space-constrained industrial and automotive modules where certification and reliability are prioritized over ultra-high energy absorption.
Availability
1SMB43CAT3 is available at Aetrix Electronics and suitable for industrial power supplies, automotive body control modules, medical sensor interfaces, and telecom line cards requiring stable component supply with full traceability and lifecycle support.
Supply support for 1SMB43CAT3 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 cloud power applications.
The 1SMB43CAT3 belongs to the SMB-series transient voltage suppressor family, engineered specifically for cost-effective, high-reliability overvoltage protection in surface-mount power systems requiring UL certification and fast response.
FAQ
What is the clamping voltage of the 1SMB43CAT3 under full-rated surge conditions?
The 1SMB43CAT3 has a maximum clamping voltage (VC) of 69.4 V when subjected to its rated peak pulse current of 8.6 A (10/1000 µs waveform). This value is measured per ON Semiconductor's standard test conditions and defines the highest voltage downstream components will experience during a full 600 W transient event. Designers must verify this clamping level remains below the absolute maximum ratings of protected ICs.
Is the 1SMB43CAT3 unidirectional or bidirectional, and how does that affect circuit placement?
The 1SMB43CAT3 is a bidirectional TVS diode, meaning it provides symmetrical clamping for both positive- and negative-polarity transients without polarity sensitivity. This eliminates the need for orientation during placement and allows single-device protection of AC-coupled signals or floating DC buses. Unlike unidirectional variants (e.g., 1SMB43AT3), no cathode/anode distinction affects functionality - both terminals behave identically.
Does the 1SMB43CAT3 meet UL 497B, and what does that certification cover?
Yes, the 1SMB43CAT3 carries UL 497B recognition (File #116110, Category QVGV2) for isolated loop circuit protection. This certification validates performance in strike voltage breakdown, endurance conditioning, dielectric withstand, and discharge testing - confirming suitability for telecom line interfaces, medical isolation barriers, and industrial fieldbus networks where safety-critical surge isolation is mandated.
What is the thermal derating behavior of the 1SMB43CAT3 above 75°C lead temperature?
The 1SMB43CAT3 derates linearly above 75°C lead temperature at 25 mW/°C, based on its specified thermal resistance from junction to lead (RJL = 40 °C/W). At 100°C lead temperature, its DC power dissipation drops from 3.0 W to 2.375 W. For pulsed operation, ambient temperature derating follows the curve in Figure 3 of the datasheet, reducing peak power capability as TA rises above 25°C.
How does the 1SMB43CAT3 compare to the 1.5SMC43CA in terms of surge handling and board space?
The 1SMB43CAT3 delivers 600 W peak power in the compact SMB (DO-214AA) package (4.06 × 3.30 mm), while the 1.5SMC43CA provides 1500 W in the larger SMC (DO-214AB) package (7.11 × 6.22 mm). The 1SMB43CAT3 is optimized for space-constrained applications where UL 497B certification and proven 600 W performance suffice; the 1.5SMC43CA suits high-energy environments where board area permits and higher surge margins are mandatory.
1SMB43CAT3 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):
- 43V
- Voltage - Breakdown (Min):
- 47.8V
- Voltage - Clamping (Max) @ Ipp:
- 69.4V
- Current - Peak Pulse (10/1000µs):
- 8.6A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- 210pF @ 1MHz
- Operating Temperature:
- -65°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- SMB
1SMB43CAT3 FAQ
1.How can I place an order for 1SMB43CAT3 through Aetrix?
Please submit a Request for Quotation (RFQ) for 1SMB43CAT3 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 1SMB43CAT3 reliable?
The price and inventory of 1SMB43CAT3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 1SMB43CAT3 is usually 5 days.
3.What payment methods are accepted for 1SMB43CAT3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 1SMB43CAT3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 1SMB43CAT3?
1SMB43CAT3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 1SMB43CAT3 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 1SMB43CAT3?
For technical support, including 1SMB43CAT3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 1SMB43CAT3 requirements.
6.How does Aetrix verify that 1SMB43CAT3 is sourced from the original manufacturer or authorized distributors?
All 1SMB43CAT3 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 1SMB43CAT3 meets industry standards.
7.What is the process for return or replacement of 1SMB43CAT3?
All 1SMB43CAT3 units undergo pre-shipment inspection (PSI). If there is an issue with 1SMB43CAT3, 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 1SMB43CAT3 part is unused and in its original packaging.
Return procedure for 1SMB43CAT3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
1SMB43CAT3 Tags
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onsemi
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DESD3V3E1BL-7B
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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