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Taiwan Semiconductor Corporation SMAJ85CA
- Part No.:
- SMAJ85CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ85CA.pdf
- Description:
- TVS DIODE 85VWM 137VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,901
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Product details
Overview
SMAJ85CA from Taiwan Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in DC power rails. It features a 85 V working stand-off voltage (VWM), 94.4–104 V breakdown voltage (VBR), 137 V maximum clamping voltage (VC) at 2.2 A peak impulse current, and 400 W peak pulse power rating per 10/1000 µs waveform.
For engineers reviewing the SMAJ85CA datasheet, SMAJ85CA pinout, SMAJ85CA application, or SMAJ85CA equivalent, this device is selected for automotive-grade surge immunity (ISO 7637-2 Pulse 1/2a/2b/3a/3b), board-level ESD/EFT hardening, and high-reliability DC/DC converter input protection where fast clamping (<1 ps response), low leakage (<1 µA @ 85 V), and bidirectional symmetry are required.
Technical Context
The SMAJ85CA implements a glass-passivated silicon junction optimized for unidirectional or bidirectional transient suppression. Its bidirectional configuration (denoted by "CA") ensures symmetrical clamping in both polarities, with identical VBR, VC, and IPPM specifications across forward and reverse directions.
It operates within -55 °C to +150 °C junction temperature range, supports 40 A non-repetitive forward surge (8.3 ms half-sine), and maintains <1 µA reverse leakage at rated VWM, enabling low-power system compatibility without standby current penalty.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 85 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR @ IT=1 mA | 94.4–104 V - Voltage at which device enters avalanche breakdown; defines minimum clamping threshold |
| VC @ IPPM=2.2 A | 137 V - Maximum voltage seen across protected circuit during 10/1000 µs surge; limits stress on downstream components |
| PPPM | 400 W - Peak transient power dissipation capability under standard 10/1000 µs waveform |
| IR @ VWM | <1 µA - Ultra-low reverse leakage preserves battery life and avoids false triggering in high-impedance circuits |
| Package | DO-214AC (SMA) - Surface-mount outline with 0.060 g mass, UL 94V-0 molding, and matte tin-plated leads |
| Standards | Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b - Validated for automotive load-dump and inductive-switching transients |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with cathode band marking; two terminals only - anode and cathode - arranged in axial orientation suitable for automated placement. Polarity is marked via a visible cathode band on the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry point in forward bias; common reference for bidirectional clamping | Connected to lower-potential side of protected line; forms symmetrical clamp path with cathode in CA configuration |
| Cathode | Current exit point in forward bias; marked with band on package | Connected to higher-potential side; enables bidirectional operation when paired with anode - no polarity dependency in surge direction |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Ensures stable, repeatable avalanche characteristics and long-term reliability under repeated surge events |
| <1 ps response time | Clamps transients before sensitive ICs experience damaging overvoltage - critical for microcontroller I/O and power supply inputs |
| Bidirectional symmetry (CA suffix) | Eliminates need for polarity-aware layout; protects AC-coupled or floating lines without external diode pairing |
| Moisture sensitivity level 1 | Enables standard SMT reflow without baking - reduces manufacturing overhead and handling risk |
| RoHS & halogen-free compliance | Meets IEC 61249-2-21 and environmental directives for industrial and automotive end equipment |
Applications
| Automotive Infotainment Power Input | Industrial PLC Digital I/O Protection |
|---|---|
Use Scenario: Protecting 12 V supply rail of head-unit MCU against load dump and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional TVS placed upstream of DC/DC converter to clamp ±100 V transients within 137 V ceiling. Use Value: Prevents reset or latch-up of ARM-based SoC during ISO 7637-2 Pulse 5a events without derating converter input specs. | Use Scenario: Shielding 24 V digital input channels from field-wiring induced surges and EFT bursts. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing 4 kV EFT (IEC 61000-4-4) and 1 kV surge (IEC 61000-4-5) at channel level. Use Value: Maintains signal integrity and eliminates false edge detection caused by transient coupling into optocoupler input stage. |
| LED Driver Secondary-Side Output | Telecom DC Power Shelf |
Use Scenario: Safeguarding constant-current LED string outputs from back-EMF during hot-plug or short-circuit recovery. IC Role / Device Role / Timing Role: Fast-clamping TVS across output terminals to limit flyback voltage spikes to ≤137 V during MOSFET turn-off. Use Value: Extends LED driver IC lifetime by preventing gate oxide stress and secondary-side rectifier avalanche failure. | Use Scenario: Front-end protection of -48 V telecom power distribution boards exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Primary-stage bidirectional suppressor absorbing 10/1000 µs surges up to 400 W before upstream fusing. Use Value: Enables single-device protection for both positive and negative rail transients without dual-diode arrays or complex layout. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ85A | Unidirectional version; same VWM, VBR, VC, but asymmetric clamping - conducts only in reverse direction | Requires correct polarity placement; unsuitable for AC or floating nodes | Select SMAJ85A only when protecting unidirectional DC rails with known polarity and ground reference |
| SMBJ85CA | Same electrical specs but in larger DO-214AA (SMB) package; 600 W PPPM rating (10/1000 µs) | Higher surge margin and thermal mass; requires larger PCB footprint and different pad layout | Choose SMBJ85CA when system-level surge testing exceeds 400 W or thermal cycling demands higher IPPM headroom |
Compared with SMAJ85A and SMBJ85CA, the SMAJ85CA uniquely balances bidirectional protection, compact DO-214AC footprint, and certified 400 W surge capacity - making it optimal for space-constrained automotive and industrial modules requiring polarity-agnostic clamping.
Availability
SMAJ85CA is available at Aetrix Electronics and suitable for automotive infotainment systems, industrial PLC I/O modules, and telecom DC power shelves requiring stable component supply, full traceability, and long-lifecycle support.
Supply support for SMAJ85CA 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, MOSFETs, and power management devices.
The SMAJ series is part of TSC's transient suppression portfolio, engineered specifically for AEC-Q200-compliant automotive and harsh-environment industrial applications demanding high surge robustness and long-term parametric stability.
FAQ
What does the "CA" suffix mean in SMAJ85CA?
The "CA" suffix in SMAJ85CA indicates a bidirectional configuration - meaning the device provides symmetrical transient suppression in both forward and reverse directions. Unlike unidirectional variants (e.g., SMAJ85A), SMAJ85CA has identical breakdown and clamping characteristics regardless of voltage polarity, eliminating polarity-dependent layout constraints and enabling use in AC-coupled or floating circuits without additional components.
Does SMAJ85CA meet automotive surge standards?
Yes, SMAJ85CA meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements for automotive electrical disturbances. Its 400 W peak pulse power rating, sub-1 ps response time, and 137 V clamping voltage at 2.2 A ensure reliable protection against load dump, inductive switching, and coupled transients in 12 V and 24 V vehicle networks - validated per manufacturer test data and application notes.
What is the maximum operating temperature for SMAJ85CA?
The SMAJ85CA has a specified operating junction temperature range of -55 °C to +150 °C. This wide thermal envelope supports deployment in under-hood automotive modules, industrial motor drives, and outdoor telecom equipment. Derating curves in the official datasheet confirm usable power dissipation down to 250 W at 85 °C ambient, ensuring robust performance in thermally demanding environments.
Can SMAJ85CA replace SMAJ85A in an existing design?
No - SMAJ85CA cannot be a direct drop-in replacement for SMAJ85A without layout review. While both share identical VWM, VBR, and VC values, SMAJ85A is unidirectional and requires correct anode/cathode orientation, whereas SMAJ85CA is bidirectional and polarity-insensitive. Swapping them may cause unintended conduction if the original design relies on directional blocking behavior.
Is SMAJ85CA RoHS and halogen-free compliant?
Yes, SMAJ85CA is fully RoHS compliant and halogen-free per IEC 61249-2-21. The device uses matte tin-plated leads, UL 94V-0 molding compound, and meets J-STD-020 moisture sensitivity level 1 - enabling lead-free reflow processing without pre-baking and supporting environmentally regulated end markets including automotive and industrial automation.
SMAJ85CA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 85V
- Voltage - Breakdown (Min):
- 94.4V
- Voltage - Clamping (Max) @ Ipp:
- 137V
- Current - Peak Pulse (10/1000µs):
- 2.2A
- Power - Peak Pulse:
- 400W
- 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-214AC (SMA)
SMAJ85CA FAQ
1.How can I place an order for SMAJ85CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ85CA 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 SMAJ85CA reliable?
The price and inventory of SMAJ85CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ85CA is usually 5 days.
3.What payment methods are accepted for SMAJ85CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ85CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ85CA?
SMAJ85CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ85CA 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 SMAJ85CA?
For technical support, including SMAJ85CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ85CA requirements.
6.How does Aetrix verify that SMAJ85CA is sourced from the original manufacturer or authorized distributors?
All SMAJ85CA 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 SMAJ85CA meets industry standards.
7.What is the process for return or replacement of SMAJ85CA?
All SMAJ85CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ85CA, 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 SMAJ85CA part is unused and in its original packaging.
Return procedure for SMAJ85CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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