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Semtech Corporation SMBJ40CA
- Part No.:
- SMBJ40CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ40CA.pdf
- Description:
- 1-LINE, 40V 9.3A TVS DO-214AA (S
- Quantity:
- Payment:
- Shipping:
Inventory:2,345
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Product details
Overview
SMBJ40CA from Littelfuse is a unidirectional transient voltage suppression (TVS) diode designed for robust overvoltage protection of DC power rails and I/O lines. It features a 40V reverse standoff voltage, 43.3V minimum breakdown voltage, 64.5V maximum clamping voltage at 32.4A peak pulse current (8/20μs), 600W peak pulse power rating, and operates across –65°C to +150°C ambient temperature. It is commonly deployed in industrial power supplies and automotive body electronics.
For engineers reviewing the SMBJ40CA datasheet, pinout, applications, or equivalent options, key selection considerations include its unidirectional polarity, DO-214AA (SMC) package compatibility with high-surge PCB layouts, low leakage (<5μA @ VRWM), and stable clamping performance under repetitive surge stress per IEC 61000-4-5 Level 4.
Technical Context
The SMBJ40CA employs a planar passivated silicon junction structure optimized for fast response (<1.0 ps) to transient overvoltages and low dynamic impedance (≈0.9Ω). Its unidirectional configuration enables integration on positive-rail-only protection paths without requiring reverse-bias blocking capability.
It meets IEC 61000-4-2 ESD immunity (±30kV air, ±30kV contact), IEC 61000-4-4 EFT (±4kV), and IEC 61000-4-5 surge (4kV line-to-earth, 2kV line-to-line) standards when applied with appropriate PCB layout-short trace lengths, direct ground plane connection, and minimal loop area.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reverse Standoff Voltage | 40 V - Maximum continuous DC or RMS voltage the device blocks without significant leakage. |
| Breakdown Voltage (Min) | 43.3 V - Voltage at which device enters avalanche conduction; ensures reliable triggering above normal operating rail. |
| Clamping Voltage (Max) | 64.5 V @ 32.4 A (8/20μs) - Peak voltage seen by protected circuit during worst-case surge; defines safe margin for downstream ICs rated ≤60 V. |
| Peak Pulse Power | 600 W - Energy-handling capacity for 8/20μs waveform; supports repeated surges up to 1000× in industrial environments. |
| Leakage Current | <5 μA @ 40 V - Negligible loading on 40V supply rails; avoids battery drain or reference drift in always-on systems. |
| Operating Temperature | –65°C to +150°C - Validated operation in under-hood automotive, industrial motor drives, and outdoor power equipment. |
Pinout & Package
Package: DO-214AA (SMC), surface-mount, molded plastic case with cathode band marking. Dimensions: 7.11 mm × 6.22 mm × 2.39 mm. RoHS-compliant, halogen-free, matte tin-plated leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to system ground or return path; completes surge shunt path during clamping event. |
| Cathode | High-side connection point | Connected to protected line (e.g., 40V rail); conducts surge current to anode when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Fast transient response | <1.0 ps turn-on time ensures protection before sensitive ICs experience overstress. |
| Low clamping ratio | VC/VBR ≈ 1.49 - Tight voltage margin between trigger and clamp improves system-level safety factor. |
| High surge repetition tolerance | Rated for ≥1000 surges at full 32.4A (8/20μs) without parameter shift - suitable for harsh industrial field deployments. |
| Stable leakage vs. temperature | <5 μA up to +125°C - maintains low standby power in thermally constrained enclosures. |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: 40V auxiliary power rail in programmable logic controller (PLC) backplane exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed directly across input capacitor to clamp surges before they reach DC-DC controllers and microcontrollers. Use Value: Limits transient voltage to ≤64.5V, preserving 60V-rated MOSFET gate drivers and analog front-end ICs without derating. |
Use Scenario: LIN bus power line (VBAT-connected) in door module subjected to ISO 7637-2 Pulse 1, 2a, and 5a. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12V/40V dual-rail BCM power input; coordinated with upstream fuse and downstream LC filter. Use Value: Withstands 100+ load-dump events while maintaining <5μA leakage-critical for low-quiescent-current sleep mode compliance. |
| Telecom Remote Radio Unit (RRU) | Renewable Energy Charge Controller |
Use Scenario: 48V DC power input to outdoor RRU enclosure subject to lightning-induced surges on tower-mounted cabling. IC Role / Device Role / Timing Role: First-stage clamping device in multi-tiered protection scheme (preceding MOV and gas discharge tube). Use Value: Fast response prevents follow-on failure of slower secondary protectors; DO-214AA footprint allows high-density placement near entry connector. |
Use Scenario: PV array input stage of MPPT charge controller where open-circuit voltage reaches 40V under STC conditions. IC Role / Device Role / Timing Role: Reverse-polarity and surge protector on solar panel input terminals, mounted with thermal pad to aluminum heatsink. Use Value: 150°C max junction temperature rating enables reliable operation in desert-mounted enclosures without forced cooling. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ40A (Littelfuse) | Identical electrical specs and package; differs only in marking (no "C" suffix denotes unidirectional variant). | No functional difference; SMBJ40A is the base unidirectional part number; SMBJ40CA is identical and cross-listed in Littelfuse documentation. | Select SMBJ40CA when sourcing from distributors listing CA suffix; functionally interchangeable with SMBJ40A. |
| P6SMB40A (ON Semiconductor) | Same DO-214AA package, 40V VRWM, but higher clamping voltage (69.4V @ 28.7A) and lower peak power (600W same, but derated faster above 25°C). | Less margin for 60V-rated downstream components; requires tighter thermal management in high-ambient designs. | Use only if SMBJ40CA is unavailable; verify clamping headroom against protected IC absolute maximum ratings. |
Compared with SMBJ40CA, SMBJ40A offers identical protection performance and drop-in compatibility, while P6SMB40A provides similar form-factor but reduced clamping precision and thermal robustness-making SMBJ40CA the preferred choice for high-reliability 40V rail protection.
Availability
SMBJ40CA is available at Aetrix Electronics and suitable for industrial power supplies, automotive body electronics, telecom remote radio units, and renewable energy charge controllers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SMBJ40CA 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, power control, and sensing technologies, serving automotive, industrial, consumer, and telecommunications markets since 1927.
The SMBJ series was developed specifically for high-energy transient suppression in space-constrained, high-reliability DC power applications-emphasizing stable clamping, low leakage, and ruggedized packaging for automotive and industrial deployment.
FAQ
What is the polarity configuration of SMBJ40CA?
The SMBJ40CA is a unidirectional TVS diode, meaning it functions as a forward-biased rectifier in normal operation and clamps only positive-going transients on the cathode side. It must be installed with cathode toward the protected line and anode to ground. This configuration ensures no conduction during negative excursions, making it ideal for single-polarity DC rails like 40V industrial supplies. SMBJ40CA does not conduct reverse current under normal bias.
Does SMBJ40CA meet IEC 61000-4-5 surge immunity requirements?
Yes, SMBJ40CA is rated for 600W peak pulse power per 8/20μs waveform, supporting IEC 61000-4-5 Level 4 (4kV line-to-earth, 2kV line-to-line) when implemented with proper PCB layout-including short traces, low-inductance ground connections, and proximity to the threat entry point. Its 64.5V clamping voltage at 32.4A ensures protected circuits remain within safe operating limits during standardized surge testing. SMBJ40CA's performance is validated per Littelfuse's published test reports.
How does SMBJ40CA compare to bidirectional TVS diodes like SMBJ40C?
SMBJ40CA is unidirectional and optimized for DC power rail protection where only positive transients occur; SMBJ40C is bidirectional and suited for AC signal lines or dual-polarity rails. SMBJ40CA offers lower leakage (<5μA) and tighter clamping ratio (VC/VBR ≈ 1.49) than SMBJ40C (VC/VBR ≈ 1.55), improving efficiency and margin in 40V DC systems. SMBJ40CA cannot replace SMBJ40C in AC-coupled applications due to polarity asymmetry.
What is the recommended PCB layout for SMBJ40CA in high-surge applications?
Place SMBJ40CA within 5 mm of the connector or threat entry point, using wide (≥2 mm), short (≤10 mm) copper traces to both cathode and anode. Connect the anode directly to a solid ground plane via multiple thermal vias (≥3× 0.3 mm diameter). Avoid routing other signals near the SMBJ40CA path. For 40V rail protection, use ≥1 oz copper and minimize loop area between protected line and ground return. SMBJ40CA's DO-214AA package supports this layout without thermal pads.
Is SMBJ40CA suitable for automotive under-hood applications?
Yes, SMBJ40CA is qualified for operation from –65°C to +150°C and meets AEC-Q200 stress test requirements for transient suppression devices. Its stable leakage (<5μA at 125°C) and consistent clamping voltage across temperature make it suitable for engine control units, body control modules, and ADAS power domains exposed to under-hood thermal cycling. SMBJ40CA's DO-214AA package withstands mechanical vibration and thermal shock typical in automotive environments.
SMBJ40CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Semtech Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJxxCA
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 175°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ40CA FAQ
1.How can I place an order for SMBJ40CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ40CA 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 SMBJ40CA reliable?
The price and inventory of SMBJ40CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ40CA is usually 5 days.
3.What payment methods are accepted for SMBJ40CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ40CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ40CA?
SMBJ40CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ40CA 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 SMBJ40CA?
For technical support, including SMBJ40CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ40CA requirements.
6.How does Aetrix verify that SMBJ40CA is sourced from the original manufacturer or authorized distributors?
All SMBJ40CA 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 SMBJ40CA meets industry standards.
7.What is the process for return or replacement of SMBJ40CA?
All SMBJ40CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ40CA, 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 SMBJ40CA part is unused and in its original packaging.
Return procedure for SMBJ40CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ40CA Tags
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