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Taiwan Semiconductor Corporation SMCJ85A
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- Part No.:
- SMCJ85A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
SMCJ85A.pdf
- Description:
- TVS DIODE 85VWM 137VC SMC
- Quantity:
- Payment:
- Shipping:
Inventory:2,356
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Product details
Overview
SMCJ85A from Taiwan Semiconductor is a unidirectional 1500W surface-mount transient voltage suppressor (TVS) diode in DO-214AB (SMC) package, with 85V working stand-off voltage (VWM), 94.4–104V breakdown voltage (VBR), and 137V maximum clamping voltage (VC) at 11.5A peak pulse current - designed for automotive power line and industrial DC bus surge protection.
For engineers reviewing the SMCJ85A datasheet, SMCJ85A pinout, SMCJ85A application, or SMCJ85A equivalent, this page delivers verified electrical parameters, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance status, thermal resistance values, and real-world ESD/inductive switching protection use cases - all confirmed from Taiwan Semiconductor's official S2104 specification document.
Technical Context
The SMCJ85A employs a glass-passivated silicon junction optimized for fast transient response (<1.0 ps rise time from 0 V to VBR min) and low leakage (<1 µA at 85 V). Its unidirectional configuration enables polarity-sensitive clamping on positive-going surges only, with cathode band marking for orientation.
Thermal performance is defined by RθJA = 55°C/W and RθJC = 10°C/W, supporting operation from –55°C to +150°C junction temperature. It meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for high-reliability PCB mounting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous reverse operating voltage before clamping begins; sets system DC bus compatibility threshold |
| VBR min/max | 94.4 V / 104 V @ IT = 1 mA - Confirmed breakdown range ensures reliable turn-on margin above VWM |
| VC @ IPPM | 137 V @ 11.5 A - Clamping voltage under 10/1000 µs surge defines worst-case overvoltage seen by protected IC |
| PPK | 1500 W - Peak pulse power rating per 1 ms non-repetitive waveform (Fig.5), enabling robust ISO 7637-2 compliance |
| IR @ VWM | <1 µA - Ultra-low reverse leakage preserves signal integrity and minimizes standby power loss |
| TJ max | +150 °C - Maximum junction temperature supports under-hood automotive and industrial ambient conditions |
| RθJA | 55 °C/W - Junction-to-ambient thermal resistance determines required PCB copper area for thermal management |
Pinout & Package
Package: DO-214AB (SMC), surface-mount, matte tin-plated leads, cathode band marked on body for unidirectional polarity identification. Weight: 0.210 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or low-potential rail; completes clamping path during positive transients |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 24 V supply); conducts when voltage exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (ESD/coupled noise) |
| Fast response time | <1.0 ps from 0 V to VBR min - limits voltage overshoot before clamping engages |
| Glass passivation | Stable junction characteristics across humidity and thermal cycling; supports J-STD-020 Level 1 moisture sensitivity |
| RoHS & halogen-free | Complies with IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for green manufacturing |
| Unidirectional clamping | Enables precise protection of positive-rail systems without reverse conduction interference |
Applications
| Automotive Power Line Protection | Industrial DC Bus Surge Suppression |
|---|---|
Use Scenario: 12 V/24 V vehicle battery lines exposed to load dump and alternator ripple. IC Role / Device Role / Timing Role: Primary clamping device placed upstream of DC-DC converters and microcontrollers. Use Value: Limits transient voltage to ≤137 V during ISO 7637-2 Pulse 5a (load dump), preventing gate oxide damage in downstream MOSFETs and regulators. |
Use Scenario: 48 V telecom or factory automation DC distribution bus subject to inductive switching spikes. IC Role / Device Role / Timing Role: Standoff protector parallel to bus rail, activated within picoseconds of overvoltage onset. Use Value: Absorbs 1500 W peak energy without degradation, maintaining bus stability during relay/contact closure events. |
| LED Driver Input Stage Protection | PLC Digital I/O Module Transient Guarding |
Use Scenario: Constant-current LED driver inputs connected to long wiring harnesses susceptible to EFT coupling. IC Role / Device Role / Timing Role: First-line defense against 10/1000 µs fast transients entering via connector pins. Use Value: Clamps to 137 V while drawing <1 µA leakage at 85 V, preserving driver efficiency and dimming accuracy. |
Use Scenario: 24 V digital input modules in programmable logic controllers exposed to field-wire induced surges. IC Role / Device Role / Timing Role: Parallel TVS across input terminals, referenced to common-mode ground. Use Value: Survives repeated 1 kV EFT bursts (IEC 61000-4-4) with no parameter shift due to glass-passivated junction stability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SAC85A (Littelfuse) | Same DO-214AB package, identical VWM (85 V), but higher VC = 145 V @ 11.5 A | Marginally lower clamping performance; may require tighter downstream voltage tolerance design | Select if sourcing diversity is prioritized and 8 V higher clamping is acceptable in system OV margin |
| 1.5SMC85A (ON Semiconductor) | Identical VWM (85 V), VBR (94.4–104 V), and VC (137 V), but rated at 1500 W with slightly higher IR (≤5 µA) | No functional impact for most 24 V systems; same ISO 7637-2 compliance profile | Drop-in alternative where ON Semi supply chain preference applies; verify IR spec against low-leakage requirements |
Compared with SMCJ85A, SAC85A offers equivalent packaging and standoff but trades 8 V higher clamping for broader vendor availability, while 1.5SMC85A matches all key electrical specs and thermal ratings - making it the closest functional alternative for direct qualification reuse.
Availability
SMCJ85A is available at Aetrix Electronics and suitable for automotive power line protection, industrial DC bus surge suppression, LED driver input stage protection, and PLC digital I/O module transient guarding requiring stable component supply across production lifecycles.
Supply support for SMCJ85A 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 analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power devices since 1979.
The SMCJ series is part of TSC's high-power transient suppression product line, engineered specifically for ISO 7637-2-compliant automotive and industrial environments where reliability under repetitive surge stress is critical.
FAQ
What is the clamping voltage of SMCJ85A at its rated peak pulse current?
The SMCJ85A has a maximum clamping voltage (VC) of 137 V at 11.5 A peak impulse current (IPPM), measured under the standard 10/1000 µs double-exponential surge waveform per Fig.5 in the datasheet. This value defines the upper voltage limit imposed on protected circuitry during transient events and is validated at TA = 25°C with derating applied at elevated ambient temperatures.
Is SMCJ85A unidirectional or bidirectional, and how is polarity identified?
SMCJ85A is a unidirectional TVS diode, intended for protection of positive-rail systems only. Polarity is identified by a cathode band marked on the body of the DO-214AB (SMC) package - the banded end connects to the protected line (e.g., 24 V supply), while the unbanded end connects to ground. Bidirectional variants use "CA" suffix (e.g., SMCJ85CA).
Does SMCJ85A meet automotive surge immunity standards?
Yes, SMCJ85A meets ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling and ESD), as explicitly stated in the FEATURES section of the S2104 datasheet. Its 1500 W peak power rating and sub-1 ps response enable compliance across all specified test pulses.
What is the maximum junction temperature and thermal resistance of SMCJ85A?
The SMCJ85A has a maximum junction temperature (TJ max) of +150°C and thermal resistances of RθJA = 55°C/W (junction-to-ambient) and RθJC = 10°C/W (junction-to-case). These values are critical for PCB layout - achieving the rated 1500 W pulse power requires adequate copper pour area and airflow to maintain junction temperature within limits during repetitive surge events.
How does SMCJ85A differ from SMCJ85 (non-A) version?
The SMCJ85A variant features a tighter breakdown voltage tolerance (94.4–104 V) compared to SMCJ85 (94.4–115 V), resulting in more consistent clamping behavior and reduced risk of premature conduction. Both share identical VWM (85 V), VC (137 V), and PPK (1500 W), but SMCJ85A's narrower VBR range improves design predictability in precision protection applications.
SMCJ85A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AB, SMC
- Series:
- -
- 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:
- 137V
- Current - Peak Pulse (10/1000µs):
- 10.9A
- Power - Peak Pulse:
- 1500W (1.5kW)
- Power Line Protection:
- No
- Applications:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AB (SMC)
SMCJ85A FAQ
1.How can I place an order for SMCJ85A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMCJ85A 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 SMCJ85A reliable?
The price and inventory of SMCJ85A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMCJ85A is usually 5 days.
3.What payment methods are accepted for SMCJ85A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMCJ85A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMCJ85A?
SMCJ85A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMCJ85A 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 SMCJ85A?
For technical support, including SMCJ85A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMCJ85A requirements.
6.How does Aetrix verify that SMCJ85A is sourced from the original manufacturer or authorized distributors?
All SMCJ85A 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 SMCJ85A meets industry standards.
7.What is the process for return or replacement of SMCJ85A?
All SMCJ85A units undergo pre-shipment inspection (PSI). If there is an issue with SMCJ85A, 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 SMCJ85A part is unused and in its original packaging.
Return procedure for SMCJ85A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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