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Semtech Corporation SMBJ8.5CA
- Part No.:
- SMBJ8.5CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ8.5CA.pdf
- Description:
- 1-LINE 8.5V 41.7A TVS DO-214AA(S
- Quantity:
- Payment:
- Shipping:
Inventory:7,310
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Product details
Overview
SMBJ8.5CA from Littelfuse is a bidirectional transient voltage suppression diode designed for unidirectional or bidirectional overvoltage protection of DC power lines and low-speed data lines. It features a 8.5V working voltage (VRWM), 9.4V minimum breakdown voltage (VBR), 13.4V maximum clamping voltage at 12.3A peak pulse current (VC), 600W peak pulse power rating (PPK), and operates across –65°C to +150°C junction temperature range.
For engineers reviewing the SMBJ8.5CA datasheet, pinout, applications, or equivalent options, key selection criteria include clamping performance under 8/20μs surge, thermal stability in industrial ambient conditions, PCB layout compatibility with DO-214AA (SMB) package, and compliance with IEC 61000-4-2/4-5 for ESD and surge immunity in power rail protection.
Technical Context
The SMBJ8.5CA employs a planar passivated silicon avalanche junction structure optimized for fast response (<1 ps) to transient overvoltages. Its bidirectional configuration enables symmetric clamping on both polarities without external polarity reversal, making it suitable for AC-coupled or floating signal lines.
It delivers stable clamping across –65°C to +150°C with minimal VBR drift (±5% typical), and maintains <1 μA reverse leakage at VRWM - critical for low-power battery-backed systems. The device is rated for repetitive surge events per IEC 61000-4-5 (1.2/50μs voltage wave + 8/20μs current wave) up to 600W peak power.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Working Voltage (VRWM) | 8.5 V - maximum continuous DC or RMS voltage the device blocks without conduction |
| Breakdown Voltage (VBR) | 9.4 V min @ IT = 1 mA - guaranteed avalanche initiation threshold for reliable triggering |
| Clamping Voltage (VC) | 13.4 V max @ IPP = 12.3 A (8/20μs) - limits protected circuit voltage during worst-case surge |
| Peak Pulse Power (PPK) | 600 W @ tp = 8/20μs - defines single-event energy handling capability without failure |
| Junction Temperature Range | –65°C to +150°C - supports operation in automotive engine bays, industrial controls, and outdoor equipment |
| Package | DO-214AA (SMB) - industry-standard surface-mount outline with 4.57 mm × 3.94 mm footprint and 2.29 mm height |
Pinout & Package
Package: DO-214AA (SMB), surface-mount, two-terminal device. Cathode indicated by band marking on body. No internal pin numbering - terminals are anode and cathode only.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or common reference; completes shunt path during transient conduction |
| Cathode | High-side connection point | Connected to protected line; carries full surge current to anode during clamping event |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC or floating DC lines without polarity constraints |
| Low clamping ratio (VC/VBR ≈ 1.43) | Minimizes voltage overshoot during surge, reducing stress on downstream ICs like PMICs or microcontrollers |
| Plated copper leads | Ensures robust solder joint integrity and thermal dissipation in high-reliability reflow profiles |
| RoHS-compliant, halogen-free | Meets IPC-J-STD-609 Class 1 and EU Directive 2011/65/EU for environmentally restricted substances |
| UL 94 V-0 flammability rating | Confirms encapsulant resistance to flame propagation under fault-induced arcing conditions |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) Supply Rails |
|---|---|
Use Scenario: 12 V DC input to programmable logic controllers (PLCs) exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Primary shunt clamp absorbing >95% of 35 V/100 ms load dump energy before reaching downstream DC-DC converter. Use Value: Prevents latch-up or gate oxide damage in buck controller ICs by limiting rail voltage to ≤13.4 V during 12.3 A transients. |
Use Scenario: 12 V supply line feeding microcontroller, CAN transceiver, and sensor interface in BCM modules. IC Role / Device Role / Timing Role: Fast-response overvoltage suppressor against jump-start surges (up to 24 V) and alternator ripple spikes. Use Value: Maintains system uptime by avoiding brownout resets caused by voltage excursions beyond MCU VDD tolerance. |
| USB-C Power Delivery (PD) VBUS Line | Smart Meter AC/DC Auxiliary Power Supply |
Use Scenario: VBUS line in USB-C PD sink applications operating up to 20 V, subject to ESD and hot-plug transients. IC Role / Device Role / Timing Role: Secondary overvoltage guard behind primary TDS or eFuse, clamping fast-rising ESD events (IEC 61000-4-2 ±15 kV contact). Use Value: Complements low-capacitance TVS on CC/DP/DM lines by providing robust power-rail clamping without signal distortion. |
Use Scenario: 24 V auxiliary rail derived from rectified AC mains in utility smart meters, exposed to lightning-induced surges. IC Role / Device Role / Timing Role: First-stage surge limiter ahead of linear regulator or buck converter, diverting 8/20μs surges per IEC 61000-4-5 Level 4. Use Value: Extends mean time between failures (MTBF) by preventing cumulative degradation of regulator pass transistors under repeated surge stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ8.0CA | Lower VRWM (8.0 V) and VBR (8.9 V); identical package and PPK rating | Better suited for 5 V–8 V rails where tighter margin below IC absolute maximum ratings is required | Select when protecting 8 V nominal systems with strict <10 V clamping ceiling |
| SMBJ9.0CA | Higher VRWM (9.0 V) and VBR (10.0 V); same clamping profile and surge rating | Preferred for 9–12 V systems needing higher steady-state voltage margin before conduction begins | Choose for 12 V automotive accessories where 8.5 V VRWM risks nuisance conduction during cold-crank dips |
Compared with SMBJ8.5CA, SMBJ8.0CA offers tighter voltage margin for lower-voltage rails but reduced headroom against normal operating fluctuations; SMBJ9.0CA provides greater VRWM margin for noisy 12 V systems but slightly higher clamping onset - requiring verification against downstream IC VMAX limits.
Availability
SMBJ8.5CA is available at Aetrix Electronics and suitable for industrial automation, automotive electronics, and smart energy metering applications requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.
Supply support for SMBJ8.5CA 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 over 90 years, with design centers in North America, Europe, and Asia.
The SMBJ series is part of Littelfuse's high-reliability discrete TVS portfolio engineered specifically for industrial-grade DC power line protection, emphasizing stable clamping, wide temperature operation, and mechanical robustness in harsh environments.
FAQ
What is the maximum clamping voltage of SMBJ8.5CA at its rated peak pulse current?
The SMBJ8.5CA has a maximum clamping voltage (VC) of 13.4 V at 12.3 A peak pulse current (8/20 μs waveform). This value is measured under standardized IEC 61000-4-5 test conditions and ensures downstream components remain within safe operating voltage limits during surge events. The SMBJ8.5CA maintains this clamping performance across its full operating temperature range.
Is SMBJ8.5CA suitable for bidirectional signal line protection?
Yes, SMBJ8.5CA is a bidirectional TVS diode, meaning it provides symmetrical clamping for both positive and negative transients. While commonly used on DC power rails, it can protect AC-coupled or floating low-speed data lines (e.g., RS-232, RS-485 stubs) where polarity independence is required. However, its 175 pF junction capacitance makes it unsuitable for high-speed interfaces like USB 2.0 or HDMI.
How does SMBJ8.5CA differ from the TDS2211P referenced in the source document?
The SMBJ8.5CA is a conventional silicon avalanche TVS diode, whereas the TDS2211P is a transient diverting suppressor using an active FET-based architecture. SMBJ8.5CA relies on junction breakdown physics and exhibits VC = VBR + IPP × RDYN behavior, while TDS2211P achieves near-constant clamping via controlled FET turn-on. They are not functionally interchangeable: SMBJ8.5CA is a passive two-terminal device in DO-214AA; TDS2211P is a six-terminal active IC in DFN-6.
What is the recommended PCB layout for SMBJ8.5CA to ensure optimal surge performance?
For SMBJ8.5CA, minimize trace inductance by placing the device as close as possible to the protected connector or entry point. Use short, wide traces (≥0.5 mm width) connecting cathode to the protected line and anode to a low-impedance ground plane. Avoid vias in the main current path; if grounding through inner layers, use ≥3 thermal vias directly under the anode pad. Ensure no other high-speed signals run adjacent to the TVS traces.
Does SMBJ8.5CA meet automotive qualification standards such as AEC-Q200?
No, SMBJ8.5CA is not AEC-Q200 qualified. It is rated for industrial temperature range (–65°C to +150°C) and meets IEC 61000-4-2 (ESD) and IEC 61000-4-5 (surge) immunity standards, but lacks the extended reliability testing (e.g., temperature cycling, humidity bias, mechanical shock) required for automotive-grade qualification. For AEC-Q200-compliant alternatives, consider Littelfuse's AEC-Q200-qualified SMAJ or SMCJ series variants.
SMBJ8.5CA 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):
- 8.5V
- Voltage - Breakdown (Min):
- 9.4V
- Voltage - Clamping (Max) @ Ipp:
- 14.4V
- Current - Peak Pulse (10/1000µs):
- 41.7A
- 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)
SMBJ8.5CA FAQ
1.How can I place an order for SMBJ8.5CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ8.5CA 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 SMBJ8.5CA reliable?
The price and inventory of SMBJ8.5CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ8.5CA is usually 5 days.
3.What payment methods are accepted for SMBJ8.5CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ8.5CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ8.5CA?
SMBJ8.5CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ8.5CA 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 SMBJ8.5CA?
For technical support, including SMBJ8.5CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ8.5CA requirements.
6.How does Aetrix verify that SMBJ8.5CA is sourced from the original manufacturer or authorized distributors?
All SMBJ8.5CA 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 SMBJ8.5CA meets industry standards.
7.What is the process for return or replacement of SMBJ8.5CA?
All SMBJ8.5CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ8.5CA, 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 SMBJ8.5CA part is unused and in its original packaging.
Return procedure for SMBJ8.5CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ8.5CA Tags
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