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Semtech Corporation SMBJ70CA
- Part No.:
- SMBJ70CA
- Manufacturer:
- Semtech Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ70CA.pdf
- Description:
- 1-LINE 70V 5.3A TVS DO-214AA(SMB
- Quantity:
- Payment:
- Shipping:
Inventory:3,126
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Product details
Overview
SMBJ70CA from Littelfuse is a bidirectional transient voltage suppression (TVS) diode designed for robust overvoltage protection of DC power lines and low-speed signal lines. It features a 70V reverse standoff voltage, 113V maximum clamping voltage at 38.9A peak pulse current (8/20μs), and 600W peak pulse power dissipation. The device is housed in a DO-214AA (SMC) package and is rated for ±30kV IEC 61000-4-2 ESD immunity, making it suitable for industrial power input protection.
For engineers reviewing the SMBJ70CA datasheet, pinout, applications, or equivalent options, key selection criteria include its precise 70V VRWM tolerance, stable clamping performance under temperature variation (–65°C to +150°C), low leakage (<1μA at VRWM), and compatibility with IPC-7351B SMC footprint standards for automated assembly.
Technical Context
The SMBJ70CA operates as a silicon avalanche diode with symmetrical (bidirectional) breakdown characteristics, enabling protection against both positive and negative transients on unidirectional or AC-coupled lines. Its junction capacitance is not specified - confirming absence of high-frequency signal line use - and its thermal resistance (RθJA ≈ 35°C/W) supports reliable operation without heatsinking up to 1.0W average power dissipation.
Unlike active transient suppressors such as the TDS2211P (which uses a triggered FET shunt), the SMBJ70CA relies on passive avalanche conduction, resulting in a clamping voltage that rises linearly with peak current per VC = VBR + IPP × RDYN. Its 113V clamping at 38.9A reflects a typical dynamic resistance of ~1.1Ω, validated across –65°C to +150°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Reverse Standoff Voltage (VRWM) | 70 V - Maximum continuous DC or RMS voltage the device blocks without significant leakage. |
| Breakdown Voltage (VBR) | 77.8–86.0 V at IT = 1 mA - Confirmed avalanche initiation threshold; ensures reliable turn-on before system damage. |
| Maximum Clamping Voltage (VC) | 113 V at IPP = 38.9 A (8/20 μs) - Peak voltage seen by protected circuit during worst-case surge; defines safe margin for downstream ICs. |
| Peak Pulse Power (PPK) | 600 W - Energy-handling capability for standardized lightning/surge events per IEC 61000-4-5. |
| Leakage Current (IR) | <1 μA at 70 V, 25°C - Negligible loading on 70V supply rails; avoids drift in precision bias networks. |
| Operating Temperature Range | –65°C to +150°C - Validated performance across extended industrial and automotive under-hood environments. |
Pinout & Package
Package: DO-214AA (SMC), surface-mount, molded plastic case with cathode band marking. Dimensions: 7.11 mm × 6.22 mm × 2.34 mm. Compliant with JEDEC DO-214AA outline and RoHS/REACH.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (marked end opposite cathode band) | Transient return path for negative surges | Connects to ground or common reference; completes bidirectional clamping loop. |
| Cathode (band-marked end) | Transient return path for positive surges | Connects to protected line; avalanche conduction initiates when line voltage exceeds VRWM + margin. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional surge suppression | Protects AC-coupled or floating lines (e.g., RS-485, CAN, sensor bridges) without polarity constraints. |
| High surge current rating (38.9 A, 8/20 μs) | Meets Level 4 IEC 61000-4-5 immunity requirements for industrial power inputs and fieldbus interfaces. |
| Low clamping ratio (VC/VRWM ≈ 1.61) | Minimizes voltage overshoot relative to working voltage - critical for 70V-rated MOSFET gate drivers and DC-DC controllers. |
| DO-214AA mechanical robustness | Withstands >200g mechanical shock and >500 cycles thermal cycling (–65°C/+150°C), ensuring reliability in harsh environments. |
Applications
| Industrial Power Input Protection | Automotive Body Control Module (BCM) Power Rails |
|---|---|
Use Scenario: 70V nominal battery-fed subsystems (e.g., HVAC actuators, lighting drivers) exposed to load dump and jump-start transients. IC Role / Device Role / Timing Role: Primary overvoltage clamp placed upstream of DC-DC converters and microcontroller power supplies. Use Value: Limits transient voltage to ≤113V, preventing latch-up or oxide rupture in 80V-rated power management ICs. |
Use Scenario: 12V/24V vehicle electrical systems where alternator load dump generates 120V+ spikes lasting 400ms. IC Role / Device Role / Timing Role: Standalone TVS on main power rail feeding BCM microcontrollers and LIN transceivers. Use Value: Absorbs 600W surge energy without degradation, maintaining <1μA leakage to avoid battery drain in sleep mode. |
| RS-485 Transceiver Bus Protection | Telecom DC Power Feeds (48V) |
Use Scenario: Long-haul industrial serial links subject to induced lightning surges and ESD coupling from adjacent cables. IC Role / Device Role / Timing Role: Common-mode clamp between A/B differential pair and local ground plane. Use Value: Symmetrical 70V standoff enables balanced protection without skewing differential signaling integrity. |
Use Scenario: Central office or remote radio unit power inputs fed from -48V telecom rectifiers with fast-rising switching noise. IC Role / Device Role / Timing Role: Secondary overvoltage guard after primary MOV-based surge suppression. Use Value: Tight 70V VRWM tolerance prevents premature conduction during normal -48V ripple (±10%), extending device lifetime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ70A | Unidirectional variant; anode grounded, cathode to line - requires explicit polarity assignment. | Suitable only for DC lines with fixed polarity; cannot protect AC or floating signals. | Select SMBJ70A only when protecting strictly unidirectional 70V rails with known ground-referenced topology. |
| SMCJ70CA | Same VRWM and VC, but in larger DO-214AB (SMC) package - 1500W PPK rating and lower thermal resistance. | Used where higher surge repetition rate or sustained power dissipation (>1W avg.) is required. | Choose SMCJ70CA when board layout allows larger footprint and system demands >600W single-event or >1.5W continuous surge handling. |
Compared with SMBJ70A, the SMBJ70CA offers polarity-agnostic protection essential for RS-485 or transformer-isolated interfaces; compared with SMCJ70CA, it trades 900W extra surge headroom for 30% smaller PCB area and tighter IPC-compliant placement - ideal for space-constrained industrial modules.
Availability
SMBJ70CA is available at Aetrix Electronics and suitable for industrial power input protection, automotive BCM power rails, RS-485 transceiver bus protection, and telecom DC power feeds requiring stable component supply and long-term lifecycle assurance.
Supply support for SMBJ70CA 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 SMBJ70CA belongs to Littelfuse's SMBJ series of high-reliability TVS diodes, engineered specifically for ruggedized DC power line protection in industrial automation, transportation, and infrastructure equipment.
FAQ
What is the maximum clamping voltage of SMBJ70CA at its rated peak pulse current?
The SMBJ70CA has a maximum clamping voltage (VC) of 113 V at 38.9 A peak pulse current (8/20 μs waveform). This value is guaranteed per the datasheet and represents the highest voltage imposed on the protected circuit during a standardized surge event. The SMBJ70CA maintains this clamping performance across its full operating temperature range (–65°C to +150°C), ensuring consistent protection in extreme environments.
Is SMBJ70CA suitable for protecting RS-485 data lines?
Yes, SMBJ70CA is suitable for RS-485 common-mode protection due to its bidirectional structure and 70 V standoff voltage, which aligns with typical RS-485 bus voltage ranges (±7 V differential, up to ±15 V common-mode). However, it must be used in conjunction with low-capacitance TVS devices on individual A/B lines if signal integrity above 1 Mbps is required - the SMBJ70CA itself has no specified capacitance and is intended for coarse overvoltage limiting, not high-speed signal clamping.
How does SMBJ70CA differ from active transient suppressors like TDS2211P?
The SMBJ70CA is a passive silicon avalanche diode, whereas the TDS2211P is an active FET-based transient diverter with a precision trigger circuit. As a result, SMBJ70CA exhibits a linear clamping voltage rise with increasing peak current (VC ≈ VBR + IPP × RDYN), while TDS2211P maintains near-constant clamping (~28 V) across its 40 A rating. SMBJ70CA offers simpler integration and lower cost; TDS2211P delivers superior clamping stability for sensitive 22 V systems like USB PD.
What is the thermal resistance (RθJA) of SMBJ70CA in standard JEDEC PCB layout?
The SMBJ70CA has a typical junction-to-ambient thermal resistance (RθJA) of 35°C/W when mounted on a standard 1-inch² copper pad (2 oz Cu, 1-layer) per JEDEC JESD51-3. This value enables reliable operation at up to 1.0 W average power dissipation without forced air or heatsinking. For higher ambient temperatures or repeated surges, derating curves in the SMBJ70CA datasheet must be applied to ensure junction temperature remains below 150°C.
Can SMBJ70CA be used in automotive applications requiring AEC-Q200 qualification?
No, the standard SMBJ70CA is not AEC-Q200 qualified. Littelfuse offers the automotive-grade variant SMBJ70CAQ, which undergoes stress testing per AEC-Q200 Rev D (including temperature cycling, humidity bias, and mechanical shock). For automotive body electronics or infotainment power rails, SMBJ70CAQ - not SMBJ70CA - must be selected to meet OEM qualification requirements. The SMBJ70CA remains appropriate for non-automotive industrial and telecom applications.
SMBJ70CA 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):
- 70V
- Voltage - Breakdown (Min):
- 77.8V
- Voltage - Clamping (Max) @ Ipp:
- 113V
- Current - Peak Pulse (10/1000µs):
- 5.3A
- 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)
SMBJ70CA FAQ
1.How can I place an order for SMBJ70CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ70CA 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 SMBJ70CA reliable?
The price and inventory of SMBJ70CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ70CA is usually 5 days.
3.What payment methods are accepted for SMBJ70CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ70CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ70CA?
SMBJ70CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ70CA 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 SMBJ70CA?
For technical support, including SMBJ70CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ70CA requirements.
6.How does Aetrix verify that SMBJ70CA is sourced from the original manufacturer or authorized distributors?
All SMBJ70CA 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 SMBJ70CA meets industry standards.
7.What is the process for return or replacement of SMBJ70CA?
All SMBJ70CA units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ70CA, 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 SMBJ70CA part is unused and in its original packaging.
Return procedure for SMBJ70CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ70CA Tags
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