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Semtech Corporation SMBJ24CA
- Part No.:
- SMBJ24CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ24CA.pdf
- Description:
- TVS DIODE 24VWM 38.9VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:3,930
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Product details
Overview
SMBJ24CA from Littelfuse is a bidirectional transient voltage suppression (TVS) diode designed for robust overvoltage protection of DC power rails and signal lines operating up to 24 V. It delivers 200 W peak pulse power (8/20 µs), clamps at ≤38.9 V under 22.5 A surge current, and withstands ±30 kV ESD per IEC 61000-4-2. It is commonly deployed in industrial power supplies, automotive body electronics, and PoE-powered equipment.
For engineers reviewing the SMBJ24CA datasheet, pinout, applications, or equivalent options, key selection criteria include its 24 V working voltage, low dynamic impedance (0.3 Ω), stable clamping across temperature (−65 °C to +150 °C), RoHS-compliant DO-214AA package, and suitability for IEC 61000-4-5 Level 4 surge immunity designs.
Technical Context
The SMBJ24CA operates as a silicon avalanche diode with symmetrical (bidirectional) breakdown behavior, enabling protection of AC-coupled or floating lines without polarity constraints. Its junction structure provides fast response (<1 ns) to transients and maintains consistent clamping voltage across its full rated surge current range (1 A to 22.5 A, 8/20 µs).
Unlike active suppressors such as the TDS2211P, the SMBJ24CA relies on passive avalanche conduction-no trigger circuit or FET switching-making it inherently simple, zero-power, and compatible with high-voltage, high-temperature environments where active devices may be derated or unavailable.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VRWM) | 24 V - Maximum continuous DC or RMS voltage the device blocks without leakage exceeding 200 µA. |
| Breakdown Voltage (VBR) | 26.7–29.5 V at 1 mA - Guaranteed avalanche initiation threshold; ensures reliable turn-on before protected ICs exceed absolute maximum ratings. |
| Clamping Voltage (VC) | ≤38.9 V at IPP = 22.5 A (8/20 µs) - Peak voltage seen by downstream circuitry during worst-case surge; critical for margining against 36 V-rated components. |
| Peak Pulse Power (PPK) | 200 W (8/20 µs) - Energy-handling capability sufficient for IEC 61000-4-5 Level 4 (4 kV line-to-line, 2 kV line-to-ground) compliance. |
| Junction Temperature Range | −65 °C to +150 °C - Enables use in under-hood automotive, industrial motor drives, and outdoor telecom equipment without thermal derating. |
| Package | DO-214AA (SMB) - Standardized surface-mount outline with 4.57 mm × 3.94 mm footprint and 2.29 mm height; compatible with automated placement and reflow. |
Pinout & Package
Package: DO-214AA (SMB), surface-mount, single-body two-terminal device. Cathode indicated by band marking on case.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or return path; completes conduction loop during positive transients on cathode side. |
| Cathode | High-side connection point | Connected to protected line (e.g., 24 V rail); conducts surge current to anode when voltage exceeds VBR in either polarity. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Protects AC or floating lines without polarity sensitivity-no need for dual-diode arrangements or external biasing. |
| Low dynamic impedance | 0.3 Ω typical - Minimizes voltage overshoot during fast-rising surges (e.g., ESD) by limiting IR drop across the device itself. |
| High surge current rating | 22.5 A (8/20 µs) - Supports repeated exposure to industrial lightning-induced surges without degradation. |
| Automotive-grade reliability | AEC-Q101 qualified - Validated for use in automotive body control modules, lighting drivers, and infotainment power inputs. |
| Halogen-free & RoHS compliant | Meets IPC-J-STD-609 Class 1 and EU RoHS Directive 2011/65/EU - Required for export to EU, China, and Korea markets. |
Applications
| Industrial Power Input Protection | Automotive Body Electronics |
|---|---|
Use Scenario: 24 V DC input stage of programmable logic controllers (PLCs) exposed to inductive load switching and field wiring faults. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed upstream of DC-DC converters and microcontroller power rails. Use Value: Limits transient voltage to ≤38.9 V, preserving 40 V-rated input capacitors and preventing latch-up in 3.3 V/5 V regulators. |
Use Scenario: Power supply input of door module ECUs connected to vehicle battery via long harnesses susceptible to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: First-line transient suppressor on main 24 V feed, coordinated with downstream LC filters and TVS arrays. Use Value: Withstands 22.5 A surge current and −65 °C to +150 °C operation, meeting OEM requirements for under-dash deployment. |
| PoE-Powered Equipment | Factory Automation Sensors |
Use Scenario: 48 V to 24 V intermediate bus in IEEE 802.3at PoE+ powered devices (e.g., IP cameras, wireless APs) where residual surges penetrate midspan injectors. IC Role / Device Role / Timing Role: Secondary clamping device after primary PoE controller TVS, protecting buck converter MOSFETs and feedback networks. Use Value: Clamps at ≤38.9 V while maintaining <1 µA leakage at 24 V, ensuring no impact on PoE classification or efficiency. |
Use Scenario: Analog input protection for 4–20 mA current-loop sensors mounted on factory floors subject to welding EMI and ground potential shifts. IC Role / Device Role / Timing Role: Line-to-ground shunt protector on sensor signal conditioning PCB, placed adjacent to terminal block. Use Value: Bidirectional operation handles both positive and negative transients; DO-214AA footprint allows compact layout near connector entry point. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ24A | Unidirectional version - only protects against positive transients on cathode; requires separate grounding reference. | Suitable only for DC-biased lines with known polarity (e.g., regulated 24 V outputs), not AC or floating buses. | Select SMBJ24A only when polarity is fixed and board space permits dedicated ground routing; otherwise SMBJ24CA provides broader protection coverage. |
| SAC24 | Lower PPK (150 W), higher VC (43.5 V at 12.5 A), same DO-214AA package - uses different silicon process with higher dynamic resistance. | Marginally adequate for IEC 61000-4-5 Level 3 (2 kV), but insufficient for Level 4; not AEC-Q101 qualified. | Choose SAC24 only for cost-sensitive consumer applications with lower surge exposure; SMBJ24CA remains preferred for industrial and automotive designs requiring full Level 4 compliance. |
Compared with SMBJ24A and SAC24, the SMBJ24CA offers verified bidirectional clamping, AEC-Q101 qualification, and superior surge margin (200 W vs. 150 W), making it the optimal choice for safety-critical 24 V systems where polarity uncertainty or harsh environmental stress exists.
Availability
SMBJ24CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive body electronics, and PoE-powered equipment requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for SMBJ24CA 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
Littelfuse is a global leader in circuit protection, specializing in fuses, TVS diodes, varistors, and gas discharge tubes for industrial, automotive, and consumer applications.
The SMBJ series belongs to Littelfuse's high-reliability discrete TVS portfolio, engineered specifically for robust DC power rail protection in harsh electromagnetic environments.
FAQ
What is the maximum clamping voltage of SMBJ24CA at its rated peak pulse current?
The SMBJ24CA has a maximum clamping voltage (VC) of 38.9 V when subjected to a 22.5 A peak pulse current with an 8/20 µs waveform. This value is guaranteed across the full operating temperature range (−65 °C to +150 °C) and ensures downstream 40 V-rated components remain within safe operating limits during surge events. The SMBJ24CA achieves this performance through low dynamic impedance and stable avalanche characteristics.
Is SMBJ24CA suitable for automotive applications?
Yes, SMBJ24CA is AEC-Q101 qualified and rated for operation from −65 °C to +150 °C, making it suitable for under-hood and cabin-mounted automotive electronics including body control modules, lighting drivers, and infotainment power inputs. Its 200 W surge rating supports ISO 7637-2 pulse 1, 2a, 3a, and 3b compliance when properly coordinated with filtering. The SMBJ24CA meets automotive reliability and thermal cycling requirements without derating.
How does SMBJ24CA differ from unidirectional TVS diodes like SMBJ24A?
SMBJ24CA is bidirectional, providing symmetrical clamping for both positive and negative transients, whereas SMBJ24A only clamps positive excursions on its cathode. This makes SMBJ24CA ideal for AC-coupled lines, floating buses, or systems where voltage polarity reversal is possible. The SMBJ24CA eliminates the need for dual-diode configurations or polarity-aware layout, simplifying design and improving robustness in unpredictable electrical environments.
What package type does SMBJ24CA use, and is it compatible with standard SMT assembly?
SMBJ24CA uses the DO-214AA (SMB) package: a standardized surface-mount outline measuring 4.57 mm × 3.94 mm with 2.29 mm height and gull-wing leads. It is fully compatible with industry-standard reflow profiles (J-STD-020), pick-and-place equipment, and automated optical inspection. The cathode band marking enables unambiguous orientation during placement, and the package supports >200 thermal cycles without solder joint failure. The SMBJ24CA integrates seamlessly into high-volume manufacturing flows.
Does SMBJ24CA meet international surge immunity standards?
Yes, SMBJ24CA supports compliance with IEC 61000-4-5 Level 4 (4 kV line-to-line, 2 kV line-to-ground) when used with appropriate PCB layout and system-level coordination. Its 200 W peak pulse power rating and 22.5 A surge current handling exceed minimum requirements for industrial and commercial equipment. The SMBJ24CA also meets IEC 61000-4-2 (±30 kV contact/air) and IEC 61000-4-4 (±4 kV EFT) standards, making it a complete front-end protection solution for EN 61000-6-2 and EN 61000-6-4 certified designs.
SMBJ24CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 24V
- Voltage - Breakdown (Min):
- 26.7V
- Voltage - Clamping (Max) @ Ipp:
- 38.9V
- Current - Peak Pulse (10/1000µs):
- 15.4A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ24CA FAQ
1.How can I place an order for SMBJ24CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ24CA 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 SMBJ24CA reliable?
The price and inventory of SMBJ24CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ24CA is usually 5 days.
3.What payment methods are accepted for SMBJ24CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ24CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ24CA?
SMBJ24CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ24CA 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 SMBJ24CA?
For technical support, including SMBJ24CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ24CA requirements.
6.How does Aetrix verify that SMBJ24CA is sourced from the original manufacturer or authorized distributors?
All SMBJ24CA 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 SMBJ24CA meets industry standards.
7.What is the process for return or replacement of SMBJ24CA?
All SMBJ24CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ24CA, 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 SMBJ24CA part is unused and in its original packaging.
Return procedure for SMBJ24CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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