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STMicroelectronics SMBJ85CA-TR
- Part No.:
- SMBJ85CA-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ85CA-TR.pdf
- Description:
- TVS DIODE 85VWM 137VC SMB
- Quantity:
- Payment:
- Shipping:
Inventory:4,180
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Product details
Overview
SMBJ85CA-TR from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for robust ESD and surge protection on signal/power lines in industrial, telecom, and automotive electronics. It delivers 600 W peak pulse power (10/1000 µs), clamps transients to 137 V at 4.6 A, operates up to 150 °C junction temperature, and features low leakage (≤0.2 µA at 25 °C) in SMB package.
For engineers reviewing the SMBJ85CA-TR datasheet, SMBJ85CA-TR pinout, SMBJ85CA-TR application, or SMBJ85CA-TR equivalent, key selection criteria include bidirectional clamping voltage (VCL = 137 V), reverse standoff voltage (VRWM = 85 V), IEC 61000-4-2 level 4 compliance (±30 kV contact/air), UL497B recognition (E136224), and SMB footprint compatibility with IPC7531.
Technical Context
This TVS diode uses planar silicon junction technology to achieve stable clamping performance across temperature (–55 °C to +150 °C) and fast response time (<1 ns). Its bidirectional architecture enables symmetrical protection against both positive and negative transients without polarity constraints.
Clamping behavior follows VCL = VCL25°C × [1 + αT(Tj – 25)], with αT = 10.6 × 10–4/°C, and dynamic resistance (RD = 3.29 Ω) directly impacts voltage overshoot under high di/dt surges like IEC 61000-4-4 (4 kV level 4).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VRWM | 85 V - Maximum continuous reverse operating voltage before clamping initiates |
| VBR (min) | 94 V - Breakdown voltage at 1 mA test current, ensuring reliable turn-on above normal operating range |
| VCL @ IPP | 137 V at 4.6 A (10/1000 µs) - Clamped voltage during worst-case surge, defining protected circuit's maximum stress |
| PPP | 600 W - Peak pulse power handling capability for 10/1000 µs waveform, critical for lightning-induced surges |
| IR (max) | 0.2 µA at 25 °C - Ultra-low leakage preserves signal integrity and battery life in high-impedance interfaces |
| Tj max | 150 °C - Enables operation in thermally demanding environments such as engine control units or PoE injectors |
| Standards | IEC 61000-4-2 level 4 (±30 kV), IEC 61000-4-4 level 4 (4 kV), UL497B (E136224) - Validated immunity for industrial and safety-critical systems |
Pinout & Package
Manufactured in the standardized SMB (DO-214AA) surface-mount package per JEDEC outline, with matte tin-plated leads compliant with J-STD-020 MSL level 1 and JESD 22-B102 E3 solderability requirements.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (Marked Band) | Anode/Cathode terminal pair | Bidirectional symmetry means either terminal serves as anode or cathode depending on transient polarity - no fixed polarity assignment |
| Anode (Unmarked End) | Anode/Cathode terminal pair | Identical electrical role to marked end; marking indicates cathode orientation for unidirectional variants only - irrelevant for SMBJ85CA |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines (e.g., RS-485, CAN FD, Ethernet PHY) without external polarity management |
| Low dynamic resistance (3.29 Ω) | Minimizes clamping voltage rise under high-current transients, reducing stress on downstream ICs like microcontrollers or transceivers |
| UL497B recognition (E136224) | Validates use as isolated loop circuit protector in safety-critical industrial instrumentation and process control systems |
| High Tj rating (150 °C) | Supports placement near heat sources (e.g., power MOSFETs, DC-DC converters) without derating, simplifying thermal layout |
Applications
| Industrial PLC I/O Modules | Automotive Body Control Modules |
|---|---|
Use Scenario: Protecting 24 V DC digital input channels from inductive kickback and ESD during field wiring. IC Role / Device Role / Timing Role: Bidirectional TVS placed between field terminal and MCU GPIO, clamping transients before they reach level-shifter or optocoupler inputs. Use Value: Prevents latch-up or permanent damage to 3.3 V/5 V logic interfaces while maintaining <0.2 µA leakage to avoid false triggering in high-impedance sensing circuits. | Use Scenario: Safeguarding LIN bus transceivers from load dump and jump-start voltage spikes in door module ECUs. IC Role / Device Role / Timing Role: TVS connected across LIN differential pair (LIN_H/L), absorbing ±137 V clamped surges within 1 ns to preserve signal integrity. Use Value: Ensures uninterrupted communication during ISO 16750-2 pulse 5a/b events by limiting bus voltage excursion below transceiver absolute maximum ratings. |
| Telecom Power over Ethernet (PoE) | Medical Patient Monitoring Interfaces |
Use Scenario: Protecting 48 V DC power and data lines in IEEE 802.3af/at PSE/PD equipment from lightning-induced surges. IC Role / Device Role / Timing Role: Bidirectional TVS installed on each twisted pair (spare/data pairs), clamping common-mode transients before magnetics and PHY ICs. Use Value: Maintains 600 W surge rating per line while meeting IEC 61000-4-5 (10/700 µs) equivalence via 10/1000 µs derating, enabling compact front-end protection. | Use Scenario: Shielding ECG electrode inputs from defibrillation pulses and hospital-grade ESD events per IEC 60601-1-2. IC Role / Device Role / Timing Role: Low-leakage TVS placed at analog front-end amplifier inputs, shunting transients before instrumentation amplifier stages. Use Value: Guarantees ≤0.2 µA leakage at body temperature (37 °C) to prevent DC offset drift and preserves >100 dB CMRR in precision biopotential measurement paths. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ85CA from Vishay (SMBJ85CA-E3/5AT) | Identical VRWM (85 V), VCL (137 V), and PPP (600 W); RD = 3.3 Ω vs. ST's 3.29 Ω - functionally matched | No difference in ESD/surge protection capability; same UL497B recognition and IEC 61000-4-2/4-4 compliance | Select for dual-sourcing flexibility where second-source qualification is required without redesign. |
| 1.5KE85CA from ON Semiconductor | Higher PPP (1500 W), larger DO-201 package (7.7 mm × 5.2 mm), VCL = 139 V - higher power but less board-space efficient | Suitable for higher-energy surges (e.g., AC mains coupling) but incompatible with dense PCB layouts requiring SMB footprint | Choose when surge energy exceeds 600 W and board space allows DO-201; not drop-in for SMB-restricted designs. |
Compared with Vishay's SMBJ85CA-E3/5AT, ST's version offers identical clamping and thermal specs with equal supply chain maturity; versus ON's 1.5KE85CA, ST's SMBJ85CA-TR trades raw power headroom for superior board-area efficiency and reflow compatibility in high-density industrial modules.
Availability
SMBJ85CA-TR is available at Aetrix Electronics and suitable for industrial PLC I/O protection, automotive body control modules, PoE power/data line safeguarding, and medical patient monitoring interfaces requiring stable component supply across long product lifecycles.
Supply support for SMBJ85CA-TR 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
STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, sensing, and control solutions for automotive, industrial, and consumer markets.
The SMBJ series belongs to ST's Transient Voltage Suppressor portfolio, engineered specifically for high-reliability, low-leakage, high-temperature surge protection in mission-critical signal and power interfaces.
FAQ
What is the maximum clamping voltage of SMBJ85CA-TR under a 10/1000 µs surge?
The maximum clamping voltage (VCL) is 137 V at 4.6 A for a 10/1000 µs waveform, measured at 25 °C ambient. This value increases with junction temperature per the coefficient αT = 10.6 × 10–4/°C, reaching approximately 142 V at Tj = 125 °C.
Does SMBJ85CA-TR meet IEC 61000-4-2 level 4 ESD requirements?
Yes - it exceeds IEC 61000-4-2 level 4 with ±30 kV air discharge and ±30 kV contact discharge ratings, verified per C = 150 pF, R = 330 Ω test conditions. Its sub-nanosecond response time ensures effective suppression before sensitive ICs experience overstress.
Can SMBJ85CA-TR replace unidirectional SMBJ85A-TR in existing designs?
No - SMBJ85CA-TR is bidirectional and lacks polarity; substituting it for unidirectional SMBJ85A-TR may compromise protection on DC-biased lines (e.g., 5 V USB VBUS). The CA variant clamps symmetrically, while the A variant only protects against reverse-polarity transients.
What is the recommended PCB footprint for SMBJ85CA-TR?
The JEDEC-standard SMB (DO-214AA) footprint per IPC7531 is required: pad length 2.60 mm, pad width 1.62 mm, center-to-center spacing 5.84 mm, with 2.07 mm overall width. Thermal relief and copper pour under the device improve power dissipation during repetitive surges.
SMBJ85CA-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 85V
- Voltage - Breakdown (Min):
- 94V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 4.6A
- 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:
- SMB
SMBJ85CA-TR FAQ
1.How can I place an order for SMBJ85CA-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ85CA-TR 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 SMBJ85CA-TR reliable?
The price and inventory of SMBJ85CA-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ85CA-TR is usually 5 days.
3.What payment methods are accepted for SMBJ85CA-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ85CA-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ85CA-TR?
SMBJ85CA-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ85CA-TR 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 SMBJ85CA-TR?
For technical support, including SMBJ85CA-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ85CA-TR requirements.
6.How does Aetrix verify that SMBJ85CA-TR is sourced from the original manufacturer or authorized distributors?
All SMBJ85CA-TR 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 SMBJ85CA-TR meets industry standards.
7.What is the process for return or replacement of SMBJ85CA-TR?
All SMBJ85CA-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ85CA-TR, 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 SMBJ85CA-TR part is unused and in its original packaging.
Return procedure for SMBJ85CA-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ85CA-TR Tags
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Diodes Incorporated
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Nexperia USA Inc.
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Toshiba Semiconductor and Storage
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Diodes Incorporated
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