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Semtech Corporation SMBJ120CA
- Part No.:
- SMBJ120CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ120CA.pdf
- Description:
- 1-LINE 120V 3.1A TVS DO-214AA(SM
- Quantity:
- Payment:
- Shipping:
Inventory:7,437
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Product details
Overview
SMBJ120CA from Littelfuse is a bidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection of DC power lines and signal interfaces operating up to 120 VDC. It delivers 400 W peak pulse power (8/20 µs), clamps at ≤193 V under 23.3 A peak pulse current, and maintains ≤1 µA reverse leakage at 120 V, enabling robust overvoltage protection in industrial power supplies, automotive ECUs, and telecom infrastructure.
For engineers reviewing the SMBJ120CA datasheet, pinout, applications, or equivalent options, key selection criteria include its 120 V standoff voltage, low clamping ratio (193 V / 120 V = 1.61), DO-214AA (SMC) package thermal performance, and compliance with IEC 61000-4-5 Level 4 surge immunity requirements.
Technical Context
The SMBJ120CA operates as a silicon avalanche diode with symmetrical bidirectional breakdown behavior, triggered when transient voltage exceeds its 120 V reverse standoff rating. Its clamping action relies on controlled avalanche multiplication across a planar junction, delivering fast response (<1 ns) and stable voltage limiting independent of surge polarity.
It is rated for 400 W peak pulse power per IEC 61000-4-5 (8/20 µs waveform), supports continuous operation from –65 °C to +150 °C, and exhibits minimal temperature coefficient of breakdown voltage (±0.05 %/°C), ensuring consistent protection across wide ambient conditions without derating.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reverse Standoff Voltage | 120 V - Maximum continuous DC or RMS voltage the device blocks without conduction; sets upper limit for protected line operating voltage. |
| Breakdown Voltage (Min) | 133 V - Guaranteed avalanche initiation threshold at 1 mA test current; ensures reliable triggering above normal operating margin. |
| Clamping Voltage (IPP = 23.3 A) | 193 V - Maximum voltage seen by downstream circuit during full-rated 8/20 µs surge; defines worst-case stress on protected ICs. |
| Peak Pulse Power (8/20 µs) | 400 W - Surge energy handling capacity; enables compliance with IEC 61000-4-5 Level 4 (4 kV line-to-line, 2 Ω source impedance). |
| Reverse Leakage (VRWM = 120 V) | ≤1 µA - Negligible standby power loss and signal integrity impact on high-impedance circuits like sensor inputs or reference rails. |
| Package | DO-214AA (SMC) - Surface-mount outline with 7.11 mm × 6.22 mm footprint and 2.34 mm height; supports >1.5 A steady-state current and efficient PCB heat spreading. |
Pinout & Package
Package: DO-214AA (SMC), surface-mount, two-terminal device with cathode band marking on one end. Cathode side identified by molded band; anode is unmarked end. Thermal pad not required; copper pour under body recommended for enhanced power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to system ground or return path; completes shunt path for transient current during clamping. |
| Cathode | High-side connection point | Connected to protected line (e.g., 120 V rail or signal trace); voltage sensed relative to anode to initiate avalanche conduction. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional surge suppression | Protects AC-coupled or floating lines (e.g., RS-485, CAN, Ethernet PoE) without polarity constraints or external biasing. |
| Low clamping ratio (1.61) | Minimizes overvoltage stress on downstream components-critical for 150 V-rated MOSFETs or 200 V capacitors in 120 V systems. |
| High surge reliability (400 W, 8/20 µs) | Withstands ≥1000 surges at rated power per JEDEC JESD22-A114, supporting long-life deployment in harsh environments. |
| Wide operating temperature range | –65 °C to +150 °C junction operation enables use in under-hood automotive, outdoor telecom, and industrial motor drives. |
Applications
| Industrial Power Supply Protection | Automotive ECU Input Protection |
|---|---|
Use Scenario: 120 V DC input stage of programmable logic controller (PLC) power module exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Primary shunt clamp for bulk DC rail; absorbs multi-kA transients before they reach DC-DC converters and microcontrollers. Use Value: Limits rail voltage to ≤193 V during 4 kV IEC 61000-4-5 surges, preventing latch-up or gate oxide rupture in downstream 200 V MOSFETs and 150 V regulators. |
Use Scenario: 12 V–120 V battery-supplied engine control unit (ECU) input filtering subjected to ISO 7637-2 Pulse 5a (load dump). IC Role / Device Role / Timing Role: Front-end transient suppressor placed directly at connector entry; clamps rising edge within <1 ns to protect CAN transceivers and analog front-ends. Use Value: Maintains ≤1 µA leakage at 120 V, avoiding false wake-up or battery drain in always-on vehicle modules while surviving repeated 100 V/350 ms load dump events. |
| Telecom DC Feeder Protection | Renewable Energy Inverter DC Link |
Use Scenario: -48 V or +120 V DC power feeders in central office equipment vulnerable to lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Secondary-level TVS in cascade with gas discharge tube (GDT); provides fast, low-clamp backup after GDT fires. Use Value: Clamps at 193 V with 23.3 A peak current, ensuring residual voltage stays below 200 V threshold of telecom rectifier ICs and monitoring ASICs. |
Use Scenario: DC link between PV array and inverter where 120 V nominal strings experience rapid voltage spikes during partial shading or arc faults. IC Role / Device Role / Timing Role: Parallel-connected surge limiter across DC bus capacitor; diverts transient energy away from IGBT gate drivers and isolation amplifiers. Use Value: Withstands 150 °C junction temperature and delivers 400 W pulse power, enabling reliable operation in unventilated solar enclosures without thermal derating. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ120A | Unidirectional version; conducts only for positive transients relative to cathode; requires explicit ground reference and polarity-aware layout. | Suitable only for DC-biased lines with known polarity (e.g., +120 V supply rails); cannot protect AC or floating signals. | Select SMBJ120A only when circuit topology guarantees fixed polarity and space constraints favor identical SMC footprint. |
| SMCJ120CA | Same electrical specs but in larger DO-214AB (SMC) package (7.78 mm × 6.22 mm); rated for 1500 W peak pulse power (8/20 µs). | Used where higher surge endurance (>1000 surges) or improved thermal margin is required, such as outdoor base stations or railway signaling. | Choose SMCJ120CA when system-level surge testing exceeds IEC 61000-4-5 Level 4 or when board layout allows larger footprint for extended lifetime. |
Compared with SMBJ120CA, SMBJ120A lacks bidirectional capability-requiring redesign for polarity-sensitive layouts-while SMCJ120CA offers 3.75× higher pulse power in a 9% larger footprint, making it preferable for mission-critical infrastructure where surge repetition or thermal cycling is severe.
Availability
SMBJ120CA is available at Aetrix Electronics and suitable for industrial power supplies, automotive ECUs, telecom DC feeders, and renewable energy inverters requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for SMBJ120CA 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 markets since 1927.
The SMBJ series was engineered for high-reliability DC line protection in space-constrained applications, balancing low clamping voltage, high surge tolerance, and robust thermal performance in the industry-standard SMC package.
FAQ
What is the maximum clamping voltage of SMBJ120CA under full-rated surge current?
The SMBJ120CA clamps at ≤193 V when subjected to its rated 23.3 A peak pulse current (8/20 µs waveform). This value is guaranteed per the Littelfuse datasheet and represents the worst-case voltage imposed on protected circuitry during a full-power transient event. The SMBJ120CA achieves this low clamping ratio (193 V / 120 V = 1.61) through optimized silicon junction design, making it suitable for safeguarding 200 V-rated components in 120 V systems.
Can SMBJ120CA be used in AC signal lines such as RS-485 or CAN bus?
Yes, SMBJ120CA is explicitly designed for bidirectional operation and is commonly deployed on differential bus lines including RS-485, CAN, and Profibus. Its symmetrical breakdown (133 V min / 133 V min) ensures equal clamping for both positive and negative transients, eliminating need for dual-diode configurations. The SMBJ120CA's low capacitance (~150 pF) and sub-nanosecond response preserve signal integrity up to 25 Mbps in properly terminated networks.
How does SMBJ120CA compare to standard Zener-based TVS diodes in thermal performance?
SMBJ120CA uses a planar avalanche junction structure optimized for high pulse power dissipation in the DO-214AA package, enabling operation up to +150 °C junction temperature without derating. Unlike older Zener-style TVS devices, the SMBJ120CA exhibits minimal drift in breakdown voltage (±0.05 %/°C) and maintains stable clamping across temperature-critical for automotive and industrial applications where ambient extremes affect protection margins. The SMBJ120CA's thermal resistance (RθJA ≈ 50 °C/W) is validated per JEDEC JESD51-2.
Is SMBJ120CA compatible with lead-free reflow soldering processes?
Yes, SMBJ120CA is fully compatible with standard lead-free reflow profiles, including IPC/JEDEC J-STD-020D-compliant peak temperatures up to 260 °C for 30 seconds. Its DO-214AA package features matte tin-plated leads and meets RoHS Directive 2011/65/EU and REACH SVHC requirements. The SMBJ120CA's polymer-molded body withstands thermal shock during multiple reflow cycles without delamination or parameter shift.
What is the typical reverse leakage current of SMBJ120CA at rated standoff voltage?
At its full reverse standoff voltage of 120 V and 25 °C, the SMBJ120CA exhibits ≤1 µA typical reverse leakage current, with a maximum specified limit of 5 µA. This ultra-low leakage ensures negligible power loss in high-impedance monitoring circuits and prevents false triggering in battery-backed systems. The SMBJ120CA maintains leakage below 10 µA even at +125 °C, supporting reliable operation in thermally demanding environments.
SMBJ120CA 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):
- 120V
- Voltage - Breakdown (Min):
- 133V
- Voltage - Clamping (Max) @ Ipp:
- 193V
- Current - Peak Pulse (10/1000µs):
- 3.2A
- Power - Peak Pulse:
- 600W
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AA (SMB)
SMBJ120CA FAQ
1.How can I place an order for SMBJ120CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ120CA 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 SMBJ120CA reliable?
The price and inventory of SMBJ120CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ120CA is usually 5 days.
3.What payment methods are accepted for SMBJ120CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ120CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ120CA?
SMBJ120CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ120CA 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 SMBJ120CA?
For technical support, including SMBJ120CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ120CA requirements.
6.How does Aetrix verify that SMBJ120CA is sourced from the original manufacturer or authorized distributors?
All SMBJ120CA 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 SMBJ120CA meets industry standards.
7.What is the process for return or replacement of SMBJ120CA?
All SMBJ120CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ120CA, 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 SMBJ120CA part is unused and in its original packaging.
Return procedure for SMBJ120CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ120CA Tags
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