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Taiwan Semiconductor Corporation SMAJ8.5A
- Part No.:
- SMAJ8.5A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ8.5A.pdf
- Description:
- TVS DIODE 8.5VWM 14.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,932
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Product details
Overview
SMAJ8.5A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for primary-side overvoltage protection in DC power rails. It features a 8.5 V working stand-off voltage (VWM), 9.44–10.40 V breakdown voltage (VBR) at 1 mA test current, and clamps transients to ≤14.4 V at 10 A peak impulse current, with 400 W peak pulse power rating per 10/1000 µs waveform.
For engineers reviewing the SMAJ8.5A datasheet, SMAJ8.5A pinout, SMAJ8.5A application, or SMAJ8.5A equivalent, this device is selected for robust ESD and surge immunity in low-voltage DC/DC converters, USB-powered adapters, and industrial sensor interfaces where fast response (<1 ps), low leakage (<1 µA @ 8.5 V), and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance are required.
Technical Context
The SMAJ8.5A operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology for stable breakdown and low capacitance. Its clamping behavior is defined by a 10/1000 µs double-exponential surge waveform, with thermal derating above 25°C per Fig.2 and maximum junction temperature of 150°C.
It supports single-die configuration with cathode band polarity marking, matte tin-plated leads compliant with J-STD-002 solderability, and meets JESD201 Class 2 whisker resistance. Moisture sensitivity level is J-STD-020 Level 1, enabling standard reflow without baking.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 8.5 V - Maximum continuous reverse operating voltage before conduction begins; sets minimum system rail margin for reliable standby operation. |
| VBR min/max | 9.44 V / 10.40 V @ 1 mA - Confirmed avalanche onset range; ensures predictable turn-on across production lots and temperature. |
| VC @ IPPM | 14.4 V @ 10 A - Clamped voltage during 10/1000 µs surge; defines worst-case voltage stress on downstream ICs. |
| PPPM | 400 W - Peak pulse power handling capability; enables protection against IEC 61000-4-5 Level 4 (4 kV) surges when properly routed. |
| IR @ VWM | <1 µA - Reverse leakage at rated stand-off; minimizes quiescent power loss in battery-backed or energy-sensitive circuits. |
| Package | DO-214AC (SMA) - Standardized surface-mount outline with 2.54 mm lead pitch; compatible with automated pick-and-place and reflow. |
| TJ max | 150 °C - Maximum junction temperature; supports operation in enclosed industrial enclosures without forced cooling. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with axial leads, cathode indicated by a band on one end. Leads are matte tin-plated, solderable per J-STD-002, and meet UL 94V-0 flammability rating. Weight ≈ 0.060 g.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node; completes conduction path during reverse transient events. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., +5V rail); carries full surge current into anode during clamping. |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Ensures stable VBR over time and temperature, reducing parameter drift in long-life industrial deployments. |
| Fast response time <1.0 ps | Activates before sensitive logic or analog circuitry sustains damage from ESD or fast-rising transients. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validated for automotive load-dump and inductive-switching immunity without external filtering components. |
| RoHS & halogen-free | Meets IEC 61249-2-21 and global environmental directives; suitable for consumer, medical, and export-bound designs. |
| Moisture sensitivity Level 1 | Eliminates pre-bake requirement prior to reflow, reducing manufacturing cycle time and cost. |
Applications
| USB Power Adapter Protection | Industrial Sensor Node Input |
|---|---|
|
Use Scenario: Protects 5 V output rail of wall-mounted USB chargers against AC line transients and hot-plug ESD. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VBUS and GND, acting as first-line clamp ahead of DC/DC controller and USB interface IC. Use Value: Limits voltage excursion to ≤14.4 V during 10 A surge, preventing latch-up or gate oxide rupture in downstream 5 V logic. |
Use Scenario: Shields analog front-end inputs of 4–20 mA loop-powered sensors exposed to field wiring surges. IC Role / Device Role / Timing Role: Standoff protector on supply rail (e.g., 12 V or 24 V), absorbing coupled noise from motor drives or relay switching. Use Value: With <1 µA leakage at 8.5 V, avoids loading precision current sources while clamping to safe levels under ISO 7637-2 Pulse 2b. |
| On-board DC/DC Converter Input | LED Driver Supply Rail |
|
Use Scenario: Secures input of buck converter powering FPGA or microcontroller from noisy 12 V board bus. IC Role / Device Role / Timing Role: Primary surge suppression element placed directly at converter input capacitor, minimizing trace inductance. Use Value: 400 W peak power rating handles repetitive 10/1000 µs pulses common in industrial control cabinets without degradation. |
Use Scenario: Guards constant-current LED driver IC supply against inductive kickback from nearby solenoid actuation. IC Role / Device Role / Timing Role: Unidirectional clamp on driver VDD rail, referenced to local ground plane with minimal loop area. Use Value: Cathode-band polarity ensures correct orientation for forward-biased blocking during normal operation and reverse clamping during surges. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ8.0A (Taiwan Semiconductor) | Lower VWM (8.0 V), slightly lower VBR (8.89–9.83 V), same DO-214AC package and 400 W rating. | Better suited for tighter 5 V ±5% rails where 8.5 V VWM risks false triggering near upper limit. | Select SMAJ8.0A if system nominal voltage is 5 V with minimal tolerance margin; otherwise SMAJ8.5A provides higher noise immunity. |
| SMBJ8.5A (ON Semiconductor) | Same VWM/VBR specs but in larger DO-214AA (SMB) package; 600 W peak power rating (10/1000 µs). | Higher power handling allows longer surge duration immunity but requires larger PCB footprint and different pad layout. | Choose SMBJ8.5A only when 600 W rating is mandatory and board space permits; SMAJ8.5A remains optimal for space-constrained 5 V systems. |
Compared with SMAJ8.0A, the SMAJ8.5A offers improved noise margin on 5 V rails; compared with SMBJ8.5A, it delivers identical electrical protection in a 30% smaller footprint-critical for compact USB-C PD adapters and modular sensor nodes.
Availability
SMAJ8.5A is available at Aetrix Electronics and suitable for USB power adapters, industrial sensor nodes, on-board DC/DC converters, and LED driver supply rails requiring stable component supply across high-volume production cycles.
Supply support for SMAJ8.5A 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs, with global distribution and AEC-Q200 qualified product lines.
The SMAJ series was developed for high-reliability, surface-mount surge protection in automotive, industrial, and consumer power systems-emphasizing fast response, low leakage, and standardized packaging for automated assembly.
FAQ
What is the maximum clamping voltage of the SMAJ8.5A under a 10 A surge?
The SMAJ8.5A clamps to a maximum of 14.4 V when subjected to a 10 A peak impulse current with a 10/1000 µs waveform. This value is measured per standard test conditions (TA = 25°C) and defines the upper voltage limit imposed on protected circuitry during transient events. The SMAJ8.5A maintains this clamping performance consistently due to its glass-passivated junction and controlled avalanche characteristics.
Is the SMAJ8.5A unidirectional or bidirectional?
The SMAJ8.5A is a unidirectional TVS diode, indicated by the absence of "C" or "CA" suffix and confirmed by its single cathode band marking. It conducts only during reverse-biased transients-protecting positive supply rails referenced to ground. For bidirectional protection (e.g., data lines), SMAJ8.5CA would be required; the SMAJ8.5A must be oriented with cathode toward the protected line.
Does the SMAJ8.5A meet automotive surge standards?
Yes, the SMAJ8.5A meets ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling), making it suitable for 12 V automotive subsystems such as body control modules and infotainment power supplies. Its 400 W rating and 150 °C TJ max support under-hood deployment when thermally managed per TSC's derating curve (Fig.2).
What is the reverse leakage current specification for the SMAJ8.5A?
The SMAJ8.5A exhibits a maximum reverse leakage current (IR) of 1 µA when biased at its full working stand-off voltage of 8.5 V, tested at TA = 25°C. This ultra-low leakage preserves efficiency in always-on or battery-operated systems and avoids unintended biasing of high-impedance analog inputs. The SMAJ8.5A maintains this spec across its full operating temperature range (−55 °C to +150 °C).
Can the SMAJ8.5A be used in place of SMAJ8.0A without design changes?
No-while both share the DO-214AC package and unidirectional configuration, the SMAJ8.5A has a 0.5 V higher VWM (8.5 V vs. 8.0 V) and correspondingly higher VBR (9.44–10.40 V vs. 8.89–9.83 V). Substituting SMAJ8.5A for SMAJ8.0A may reduce noise immunity margin on tightly regulated 5 V rails. System validation is required before interchange; the SMAJ8.5A is not a drop-in replacement for SMAJ8.0A.
SMAJ8.5A 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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 8.5V
- Voltage - Breakdown (Min):
- 9.44V
- Voltage - Clamping (Max) @ Ipp:
- 14.4V
- Current - Peak Pulse (10/1000µs):
- 27.8A
- 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)
SMAJ8.5A FAQ
1.How can I place an order for SMAJ8.5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ8.5A 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 SMAJ8.5A reliable?
The price and inventory of SMAJ8.5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ8.5A is usually 5 days.
3.What payment methods are accepted for SMAJ8.5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ8.5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ8.5A?
SMAJ8.5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ8.5A 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 SMAJ8.5A?
For technical support, including SMAJ8.5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ8.5A requirements.
6.How does Aetrix verify that SMAJ8.5A is sourced from the original manufacturer or authorized distributors?
All SMAJ8.5A 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 SMAJ8.5A meets industry standards.
7.What is the process for return or replacement of SMAJ8.5A?
All SMAJ8.5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ8.5A, 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 SMAJ8.5A part is unused and in its original packaging.
Return procedure for SMAJ8.5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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