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Taiwan Semiconductor Corporation SMBJ85
- Part No.:
- SMBJ85
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ85.pdf
- Description:
- 600W, 104.7V, 10%, UNIDIRECTIONA
- Quantity:
- Payment:
- Shipping:
Inventory:7,653
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Product details
Overview
SMBJ85 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power rails and signal lines. It features a 85 V working stand-off voltage (VWM), 94.4–115 V breakdown voltage (VBR), 151 V maximum clamping voltage (VC) at 4.1 A peak pulse current, and 600 W peak pulse power rating with <1.0 ps response time - deployed in automotive lighting control modules to suppress load-dump and inductive switching transients.
For engineers reviewing the SMBJ85 datasheet, SMBJ85 pinout, SMBJ85 application, or SMBJ85 equivalent, key selection criteria include clamping voltage margin relative to protected IC's absolute maximum rating, leakage current at operating voltage, thermal derating above 25°C ambient, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive electronics.
Technical Context
The SMBJ85 uses a glass-passivated silicon junction optimized for fast avalanche response and stable clamping under repetitive 10/1000 µs surges. Its DO-214AA (SMB) package provides low thermal resistance (RθJA = 55 °C/W) and supports automated placement with matte tin-plated leads compliant to J-STD-002.
It operates across -55 °C to +150 °C junction temperature range, meets JESD201 Class 2 whisker resistance, and is rated for moisture sensitivity level 1 per J-STD-020 - enabling use in reflow-soldered industrial and automotive PCB assemblies without baking preconditioning.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous DC or RMS voltage the device blocks without clamping; sets upper limit for protected circuit's normal operating voltage. |
| VBR min/max | 94.4 V / 115 V @ 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on before downstream IC damage during overvoltage events. |
| VC @ IPP | 151 V @ 4.1 A - Clamped voltage during 10/1000 µs surge; must remain below protected IC's absolute max rating (e.g., 160 V for many automotive MCUs). |
| PPK | 600 W - Peak non-repetitive pulse power handling; defines single-event surge energy capacity (e.g., 600 W × 1 ms = 0.6 J). |
| ID @ VWM | ≤1 µA - Reverse leakage at 85 V; negligible power loss and no measurable impact on high-impedance bias networks. |
| TJ max | +150 °C - Maximum junction temperature; enables operation in under-hood automotive environments with proper board-level thermal design. |
Pinout & Package
DO-214AA (SMB) surface-mount package: cathode-banded monolithic silicon junction diode with two terminals - anode and cathode - housed in molded epoxy case meeting UL 94V-0 flammability rating and weighing ~0.090 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; completes conduction path during reverse-biased surge clamping. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 12 V battery rail); carries full surge current into anode during transient suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Clamping performance | 151 V max VC at 4.1 A ensures robust protection of 12 V/24 V automotive systems against ISO 7637-2 Pulse 2b (load dump) and Pulse 5a. |
| Response speed | <1.0 ps junction response enables suppression before ESD or fast transients propagate into sensitive analog front-ends or CAN transceivers. |
| Leakage control | <1 µA ID at 85 V prevents signal integrity degradation in high-impedance sensor biasing or precision reference circuits. |
| Automated assembly support | Glass-passivated junction and matte tin-plated leads meet J-STD-002 solderability and JESD201 Class 2 whisker resistance for high-yield SMT production. |
Applications
| Automotive Lighting Control | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting LED driver ICs and MOSFET gate drivers in headlamp control units subjected to 12 V battery load-dump transients up to 35 V. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VBAT rail and ground to clamp surges before they reach power management ICs. Use Value: 151 V clamping voltage provides ≥20 V margin below typical 170 V absolute max rating of automotive buck controllers, preventing latch-up or permanent failure. |
Use Scenario: Safeguarding 24 V digital input channels in programmable logic controllers exposed to inductive kickback from solenoid valves and relay coils. IC Role / Device Role / Timing Role: Standoff diode connected across input terminals to absorb reverse EMF spikes during coil de-energization. Use Value: 600 W peak power rating handles 100 mJ+ energy pulses (per 10/1000 µs standard), eliminating need for external snubbers in DIN-rail mounted I/O modules. |
| DC Power Rail Protection | ESD-Sensitive Interface Protection |
Use Scenario: Securing 48 V intermediate bus in telecom power supplies against coupling from adjacent AC-DC converters or lightning-induced surges. IC Role / Device Role / Timing Role: Primary surge limiter on main DC output, coordinated with downstream ceramic capacitors and ferrite beads. Use Value: 85 V VWM allows direct placement on 48 V systems with 2× safety margin, while 151 V VC avoids triggering overvoltage shutdown in PMICs with 160 V OVP thresholds. |
Use Scenario: Shielding RS-485 transceiver pins in smart meter communication interfaces from ±8 kV contact ESD per IEC 61000-4-2. IC Role / Device Role / Timing Role: Low-capacitance TVS (CJ ≈ 100 pF at 0 V) placed directly at connector entry point. Use Value: Sub-nanosecond response captures ESD events before transceiver internal protection diodes activate, reducing stress and improving long-term reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ85A | Same VWM (85 V), lower VC (142 V @ 4.3 A), higher IPP (4.3 A vs. 4.1 A), identical DO-214AC (SMA) footprint but smaller thermal mass. | Better clamping margin for 160 V-rated ICs; less suitable for high-temperature ambient (>105 °C) due to higher RθJA (~70 °C/W). | Select when tighter clamping voltage is critical and board layout allows SMA package; verify thermal dissipation in enclosed enclosures. |
| ON Semiconductor SMCJ85A | Same VWM (85 V), identical VC (151 V @ 4.1 A), same DO-214AB (SMC) package - larger than SMB, with higher PPK (1500 W) and lower RθJA (35 °C/W). | Over-specified for 600 W needs; occupies more PCB area but offers superior thermal headroom in high-power industrial motor drives. | Choose when system-level surge testing exceeds IEC 61000-4-5 Level 4 (4 kV/2 Ω) or when extended thermal cycling life is required. |
Compared with SMBJ85, SMAJ85A delivers lower clamping voltage in a smaller footprint but reduced thermal robustness, while SMCJ85A trades PCB space for higher surge endurance and better heat spreading - making SMBJ85 the optimal balance of size, clamping, and thermal performance for space-constrained automotive and industrial boards.
Availability
SMBJ85 is available at Aetrix Electronics and suitable for automotive lighting control, industrial PLC I/O protection, and 48 V DC power rail protection requiring stable component supply, consistent lead-time visibility, and RoHS/halogen-free compliance.
Supply support for SMBJ85 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
Taiwan Semiconductor Corporation (TSC) is a vertically integrated Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.
The SMBJ series was developed specifically for AEC-Q101-compliant transient suppression in harsh-environment automotive subsystems and high-reliability industrial controls - emphasizing low leakage, stable clamping, and automated assembly readiness.
FAQ
What is the maximum clamping voltage of SMBJ85 under standard 10/1000 µs surge conditions?
The SMBJ85 has a maximum clamping voltage (VC) of 151 V when subjected to its rated peak pulse current of 4.1 A using the standardized 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and confirmed in Taiwan Semiconductor's R2104 datasheet, ensuring predictable overvoltage limiting for downstream components.
Is SMBJ85 unidirectional or bidirectional, and how is polarity identified?
SMBJ85 is a unidirectional TVS diode, indicated by the absence of "C" or "CA" suffix. Polarity is marked by a cathode band on the DO-214AA (SMB) package body - the banded end connects to the protected line (e.g., 12 V rail), while the unbanded end connects to ground. Bidirectional variants require explicit "C" suffix (e.g., SMBJ85C).
Does SMBJ85 meet automotive surge immunity standards such as ISO 7637-2?
Yes, SMBJ85 meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements as stated in the official Taiwan Semiconductor documentation. Its 600 W peak power rating, fast <1.0 ps response, and controlled clamping behavior make it suitable for protecting ECUs, lighting modules, and body control units in 12 V and 24 V vehicle architectures.
What is the junction-to-ambient thermal resistance (RθJA) of SMBJ85, and why does it matter?
The SMBJ85 has a junction-to-ambient thermal resistance (RθJA) of 55 °C/W, measured under standard JEDEC test conditions. This parameter determines how much the junction temperature rises above ambient per watt of dissipated surge energy - critical for verifying safe operation during repeated transients or elevated ambient temperatures in engine compartments or industrial enclosures.
Can SMBJ85 be used in place of SMBJ85A, and what is the key difference?
No - SMBJ85 and SMBJ85A are not interchangeable without design review. SMBJ85A has tighter VBR tolerance (94.4–104 V vs. 94.4–115 V), lower clamping voltage (137 V vs. 151 V), and higher IPP (4.6 A vs. 4.1 A). The "A" suffix denotes improved uniformity and lower VC, making SMBJ85A preferable where clamping margin is constrained, but SMBJ85 remains valid for cost-sensitive or legacy designs.
SMBJ85 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 151V
- Current - Peak Pulse (10/1000µs):
- 4.1A
- 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)
SMBJ85 FAQ
1.How can I place an order for SMBJ85 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ85 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 SMBJ85 reliable?
The price and inventory of SMBJ85 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ85 is usually 5 days.
3.What payment methods are accepted for SMBJ85?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ85 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ85?
SMBJ85 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ85 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 SMBJ85?
For technical support, including SMBJ85 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ85 requirements.
6.How does Aetrix verify that SMBJ85 is sourced from the original manufacturer or authorized distributors?
All SMBJ85 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 SMBJ85 meets industry standards.
7.What is the process for return or replacement of SMBJ85?
All SMBJ85 units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ85, 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 SMBJ85 part is unused and in its original packaging.
Return procedure for SMBJ85:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMBJ85 Tags
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