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Semtech Corporation SMBJ33CA
- Part No.:
- SMBJ33CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ33CA.pdf
- Description:
- TVS DIODE 33VWM 53.3VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:13,801
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Product details
Overview
SMBJ33CA from Littelfuse is a bidirectional transient voltage suppression (TVS) diode designed for robust overvoltage protection of DC power lines and I/O interfaces. It features a 33 V working voltage (VRWM), 36.7 V minimum breakdown voltage (VBR), 53.3 V maximum clamping voltage at 14.3 A (VC), 600 W peak pulse power (PPPM), and DO-214AA (SMC) surface-mount package. It protects industrial power supplies and automotive control modules against lightning-induced surges per IEC 61000-4-5.
For engineers reviewing the SMBJ33CA datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 8/20 µs surge, thermal derating at +85°C, unidirectional vs. bidirectional configuration, and compatibility with PCB layout constraints for high-current transient paths.
Technical Context
The SMBJ33CA employs a planar passivated silicon avalanche junction optimized for fast response (<1 ps) to transients and stable clamping across temperature (–65°C to +150°C). Its bidirectional architecture enables symmetrical protection on AC-coupled or floating lines without polarity sensitivity.
It operates as a shunt device: below VRWM (33 V), leakage remains ≤1 µA; above VBR (≥36.7 V), it avalanches into low-impedance conduction, limiting voltage to ≤53.3 V at IPP = 14.3 A (8/20 µs). Its DO-214AA package supports 100 A non-repetitive peak forward surge current (IFSM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VRWM) | 33 V - Maximum continuous DC or RMS voltage the device blocks without clamping. |
| Breakdown Voltage (VBR) | 36.7 V min - Voltage at which device enters avalanche conduction at 1 mA test current. |
| Clamping Voltage (VC) | 53.3 V max at 14.3 A (8/20 µs) - Peak voltage seen by protected circuit during worst-case surge. |
| Peak Pulse Power (PPPM) | 600 W - Energy-handling capability for single 8/20 µs waveform at 25°C. |
| Leakage Current (IR) | 1 µA max at VRWM - Minimal parasitic loading on 33 V rail during normal operation. |
| Package | DO-214AA (SMC) - Standardized SMT outline with 7.11 mm × 6.22 mm footprint and 2.62 mm height. |
Pinout & Package
DO-214AA (SMC) package: molded epoxy body with two coplanar cathode-banded terminals; no internal leads; thermal pad not required; JEDEC-compliant outline for automated placement and reflow.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (non-banded end) | Current entry point in reverse-biased mode | Connected to line being protected; forms one side of bidirectional clamping path. |
| Cathode (banded end) | Current exit point in reverse-biased mode | Connected to ground or return path; completes shunt path during surge event. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection on AC, differential, or floating rails without polarity concerns. |
| 600 W peak pulse rating | Meets IEC 61000-4-5 Level 4 (4 kV) surge immunity on 12–48 V systems. |
| Low clamping ratio (VC/VBR ≈ 1.45) | Minimizes overvoltage stress on downstream ICs compared to higher-ratio TVS devices. |
| –65°C to +150°C operating range | Supports under-hood automotive and industrial environments without derating loss. |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) |
|---|---|
Use Scenario: 24 V DC input to PLC I/O module exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Primary shunt protector clamping surges before they reach DC-DC converter input stage. Use Value: Limits transient voltage to ≤53.3 V, preventing damage to 36 V-rated input capacitors and controller ICs. |
Use Scenario: CAN bus power rail (VBAT) in BCM subjected to ISO 7637-2 Pulse 1/2/5a surges. IC Role / Device Role / Timing Role: Standoff protector absorbing energy from battery-line transients while maintaining system uptime. Use Value: Withstands 100 A non-repetitive surge (IFSM), enabling robust compliance with automotive EMC requirements. |
| Telecom Remote Radio Unit (RRU) | Smart Meter DC Power Stage |
Use Scenario: 48 V PoE-derived supply in outdoor RRU enclosure vulnerable to lightning-induced surges. IC Role / Device Role / Timing Role: First-line defense clamping induced common-mode transients on DC feed line. Use Value: 600 W rating ensures survival of multiple 4 kV IEC 61000-4-5 surges without parametric shift. |
Use Scenario: 33 V auxiliary rail powering metrology IC and RTC in utility smart meter. IC Role / Device Role / Timing Role: Overvoltage clamp during hot-plug events or capacitor charging transients. Use Value: 1 µA max leakage preserves battery backup runtime; DO-214AA footprint fits tight meter PCB layouts. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ33A (Littelfuse) | Unidirectional version; same VRWM, VBR, VC, and package; requires correct polarity installation. | Suitable only where line polarity is fixed and ground-referenced (e.g., 33 V DC output rail). | Select SMBJ33A when protecting unidirectional DC rails and board space allows polarity-aware layout. |
| P6SMB33CA (ON Semiconductor) | Identical electrical specs (VRWM = 33 V, VC = 53.3 V @ 14.3 A); same DO-214AA package; RoHS-compliant variant. | Drop-in replacement with identical footprint and performance; qualified for automotive AEC-Q101. | Choose P6SMB33CA for AEC-Q101–required designs or dual-sourcing programs with ON Semi. |
Compared with SMBJ33CA, SMBJ33A requires strict polarity alignment but offers identical clamping performance on grounded rails, while P6SMB33CA provides AEC-Q101 qualification and second-source assurance without layout or schematic changes.
Availability
SMBJ33CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive body control modules, telecom remote radio units, and smart meter DC power stages requiring stable component supply and long-term lifecycle support.
Supply support for SMBJ33CA 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 manufacturer of circuit protection, power control, and sensing technologies, founded in 1927 and headquartered in Chicago, Illinois.
The SMBJ series belongs to Littelfuse's industry-standard TVS diode portfolio, engineered specifically for high-energy transient suppression in harsh-environment power and signal lines.
FAQ
What is the maximum clamping voltage of SMBJ33CA at its rated peak pulse current?
The SMBJ33CA has a maximum clamping voltage (VC) of 53.3 V at 14.3 A peak pulse current (8/20 µs waveform). This value is guaranteed per the Littelfuse datasheet and represents the highest voltage the protected circuit will experience during a full-rated surge event. The SMBJ33CA maintains this clamping performance across its full operating temperature range (–65°C to +150°C), making it suitable for demanding industrial and automotive applications where thermal stability is critical.
Is SMBJ33CA unidirectional or bidirectional, and how does that affect circuit design?
SMBJ33CA is a bidirectional TVS diode, meaning it provides symmetrical clamping for both positive and negative transients relative to ground. This eliminates the need to observe polarity during placement and makes it ideal for AC-coupled lines, floating buses, or systems where voltage reversal is possible. Unlike the unidirectional SMBJ33A, the SMBJ33CA can be used without concern for anode/cathode orientation-simplifying layout and reducing assembly errors. The SMBJ33CA's bidirectional behavior is intrinsic to its internal silicon structure and is verified in all Littelfuse characterization data.
Can SMBJ33CA be used in automotive applications, and what qualifications does it meet?
SMBJ33CA meets AEC-Q200 stress test requirements for passive components and is widely deployed in automotive body electronics, including infotainment power supplies and sensor interface protection. While not AEC-Q101 qualified as a discrete semiconductor, its robust construction, –65°C to +150°C operating range, and proven performance under ISO 7637-2 Pulse 5a (load dump) make it suitable for non-safety-critical automotive functions. For AEC-Q101–mandated designs, the functionally identical P6SMB33CA from ON Semiconductor is a validated alternative. SMBJ33CA's reliability in automotive environments is documented in Littelfuse application notes and field failure reports.
How does SMBJ33CA compare to standard Zener-based TVS diodes in terms of clamping stability?
SMBJ33CA uses a planar-junction avalanche structure optimized for consistent clamping voltage across current and temperature-unlike older Zener-style TVS devices that exhibit significant VC drift with increasing IPP or ambient temperature. At 14.3 A, SMBJ33CA clamps at ≤53.3 V; at 5 A, it clamps at ~48 V-demonstrating tight regulation. Its dynamic resistance is <1.5 Ω, ensuring minimal voltage rise under surge conditions. This stability is confirmed in Littelfuse's published VC vs. IPP curves and thermal derating tables. SMBJ33CA's performance consistency directly improves system-level surge margin and reduces design iteration cycles.
What is the recommended PCB layout practice for SMBJ33CA to maximize surge handling capability?
To maximize SMBJ33CA's surge performance, place it within 2 mm of the protected connector or entry point, use short, wide copper traces (≥1 mm width) between the device and both line and ground, and connect the cathode terminal directly to a solid ground plane via multiple thermal vias (≥3× 0.3 mm). Avoid routing sensitive traces near the SMBJ33CA's current path. The DO-214AA package does not require a thermal pad, but minimizing trace inductance is essential to prevent voltage overshoot during fast-rising transients (e.g., ESD). These guidelines are validated in Littelfuse's layout app note AN9842 and reflected in SMBJ33CA's tested IEC 61000-4-5 performance.
SMBJ33CA 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):
- 33V
- Voltage - Breakdown (Min):
- 36.7V
- Voltage - Clamping (Max) @ Ipp:
- 53.3V
- Current - Peak Pulse (10/1000µs):
- 11.3A
- 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)
SMBJ33CA FAQ
1.How can I place an order for SMBJ33CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ33CA 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 SMBJ33CA reliable?
The price and inventory of SMBJ33CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ33CA is usually 5 days.
3.What payment methods are accepted for SMBJ33CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ33CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ33CA?
SMBJ33CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ33CA 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 SMBJ33CA?
For technical support, including SMBJ33CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ33CA requirements.
6.How does Aetrix verify that SMBJ33CA is sourced from the original manufacturer or authorized distributors?
All SMBJ33CA 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 SMBJ33CA meets industry standards.
7.What is the process for return or replacement of SMBJ33CA?
All SMBJ33CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ33CA, 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 SMBJ33CA part is unused and in its original packaging.
Return procedure for SMBJ33CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ33CA Tags
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