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STMicroelectronics SMAJ8.5CA-TR
- Part No.:
- SMAJ8.5CA-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ8.5CA-TR.pdf
- Description:
- TVS DIODE 8.5VWM 19.5VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:27,241
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Product details
Overview
SMAJ8.5CA-TR from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for ESD and surge protection in low-voltage DC power rails and signal lines. It features a standoff voltage (VRM) of 8.5 V, minimum breakdown voltage (VBR) of 9.4 V at 1 mA, clamping voltage (VCL) of 14.4 V at 27.7 A (10/1000 µs), peak pulse power of 400 W, and operates up to 150 °C junction temperature - deployed in industrial I/O, USB ports, and automotive body electronics.
For engineers reviewing the SMAJ8.5CA-TR datasheet, SMAJ8.5CA-TR pinout, SMAJ8.5CA-TR application, or SMAJ8.5CA-TR equivalent, key selection criteria include bidirectional clamping behavior, low leakage (<1 µA at 85 °C), JEDEC DO-214AC (SMA) package compatibility, and IEC 61000-4-2/4-4 level 4 compliance for robust system-level ESD/surge immunity.
Technical Context
This TVS diode uses planar silicon technology to achieve stable breakdown characteristics and low leakage across temperature. Its bidirectional configuration enables symmetrical clamping on AC-coupled or floating signal paths without polarity constraints.
The device complies with IEC 61000-4-2 (±30 kV contact/air discharge) and IEC 61000-4-4 (4 kV, 5/50 ns), with dynamic resistance (RD) of 0.145 Ω at 25 °C - enabling fast response and minimal voltage overshoot during sub-microsecond transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 8.5 V - maximum continuous reverse operating voltage before significant leakage begins |
| Breakdown Voltage (VBR) | 9.4 V min at 1 mA - ensures reliable triggering above normal rail voltage with margin |
| Clamping Voltage (VCL) | 14.4 V at 27.7 A (10/1000 µs) - limits downstream voltage stress during surge events |
| Peak Pulse Power | 400 W (10/1000 µs) - sustains common lightning-induced surges per IEC 61000-4-5 |
| Leakage Current (IRM) | 20 µA max at 8.5 V, 25 °C - preserves signal integrity and battery life in always-on circuits |
| Junction Temperature Range | −55 °C to +150 °C - supports under-hood automotive and industrial ambient conditions |
| Package | DO-214AC (SMA) - surface-mount footprint compliant with IPC-7531, MSL Level 1 |
Pinout & Package
Encapsulated in the JEDEC DO-214AC (SMA) package, SMAJ8.5CA-TR is a two-terminal bidirectional device with no polarity marking - both leads serve as symmetrical anode/cathode terminals depending on transient polarity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (Pin 1 & 2) | Reversible transient current path | Identical terminals; bidirectional conduction allows placement without orientation concern on PCB |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables protection of AC signals, differential buses (e.g., RS-485), and ungrounded interfaces without polarity sensitivity |
| Low dynamic resistance | 0.145 Ω at 25 °C - minimizes clamping voltage rise under high-current transients |
| High-temperature reliability | Rated to 150 °C TJ - maintains performance in thermally constrained enclosures and engine compartments |
| IEC 61000-4-2 Level 4 compliance | Withstands ±30 kV air/contact discharge - exceeds standard requirements for industrial and automotive end-equipment |
| Planar junction construction | Delivers tight VBR tolerance and stable leakage vs. temperature - critical for long-term field reliability |
Applications
| Industrial PLC I/O Protection | Automotive Body Control Module |
|---|---|
Use Scenario: Protecting 12 V CAN/LIN bus stubs and sensor inputs against load dump and ESD in factory automation cabinets. IC Role / Device Role / Timing Role: Standoff-clamp TVS placed directly at connector entry point to shunt transients before reaching MCU GPIO or transceiver ICs. Use Value: Clamps 14.4 V at 27.7 A while maintaining <20 µA leakage - prevents false triggering and preserves low-power sleep modes. | Use Scenario: Safeguarding door module microswitch inputs and LED driver feedback lines exposed to 12 V battery rail noise and jump-start spikes. IC Role / Device Role / Timing Role: Bidirectional transient suppressor mounted adjacent to connector pins to absorb ±30 kV ESD and 4 kV burst noise per IEC 61000-4-4. Use Value: Operates reliably up to 150 °C junction temperature - meets AEC-Q101 thermal stress requirements without derating. |
| USB 2.0 Data Line Protection | Smart Meter Communication Interface |
Use Scenario: Shielding D+/D− lines of embedded USB peripherals from human-body-model ESD during plug/unplug cycles. IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS placed inline with data traces to limit voltage excursion without distorting 480 Mbps signaling. Use Value: Junction capacitance <100 pF at 0 V (per typical curve for SMAJ8.5CA) - avoids signal integrity degradation in high-speed USB links. | Use Scenario: Hardening RS-485 transceivers in utility meters against induced surges from nearby lightning strikes on power distribution lines. IC Role / Device Role / Timing Role: Primary front-end surge clamp on differential bus lines, coordinated with secondary GDT or MOV stages. Use Value: 400 W peak pulse rating (10/1000 µs) provides sufficient energy absorption margin before upstream fusing activates. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ8.5CA | Same VRM/VBR/VCL specs but in larger DO-214AA (SMB) package; 600 W peak power rating | Higher power handling suits higher-energy surge environments; requires larger PCB footprint | Select when surge threat exceeds 400 W or board layout allows SMB footprint |
| P6SMB8.5CA | Identical electrical specs and DO-214AA package; manufactured by Littelfuse; RoHS-compliant variant | No functional difference; validated alternate sourcing for supply chain diversification | Preferred for dual-sourcing programs requiring second-source qualification |
Compared with SMBJ8.5CA and P6SMB8.5CA, SMAJ8.5CA-TR offers optimal space efficiency in compact designs while delivering full IEC 61000-4-2/4-4 compliance - making it ideal for space-constrained industrial and automotive modules where footprint and thermal performance are prioritized over ultra-high surge margin.
Availability
SMAJ8.5CA-TR is available at Aetrix Electronics and suitable for industrial I/O protection, automotive body electronics, USB interface hardening, and smart meter communication interfaces requiring stable component supply and full traceability.
Supply support for SMAJ8.5CA-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, designing and manufacturing analog, power, microcontroller, and sensor solutions for industrial, automotive, and consumer markets.
SMAJxxCA belongs to ST's TVS Diode portfolio targeting system-level EMC protection - engineered specifically for robust, low-leakage, high-temperature operation in harsh environments per IEC and AEC standards.
FAQ
What does the "CA" suffix indicate in SMAJ8.5CA-TR?
The "CA" denotes a bidirectional configuration: both terminals function symmetrically as anode and cathode depending on transient polarity. Unlike unidirectional "A" variants, SMAJ8.5CA-TR clamps positive and negative surges equally - essential for protecting AC-coupled or floating signal lines such as RS-485, USB D+/D−, or audio interfaces without polarity constraints.
How does SMAJ8.5CA-TR perform under elevated temperature?
At 85 °C, its maximum leakage current remains ≤1 µA (vs. 0.2 µA at 25 °C), and clamping voltage increases predictably per αT = 7.3 × 10⁻⁴/°C - resulting in ~15.1 V VCL at 85 °C and 27.7 A. The device maintains full functionality across −55 °C to +150 °C junction range, with no derating required up to 125 °C ambient in standard PCB layouts.
Can SMAJ8.5CA-TR be used in parallel for higher surge current handling?
No - paralleling TVS diodes is not recommended due to mismatched dynamic resistance and VBR tolerances, which cause uneven current sharing and premature failure of the lower-VBR unit. For higher current capability, select a single higher-rated device like SMBJ8.5CA (600 W) or use staged protection (e.g., GDT + TVS) rather than parallel TVS arrays.
Is the SMAJ8.5CA-TR RoHS and REACH compliant?
Yes - SMAJ8.5CA-TR is manufactured in ST's ECOPACK2-compliant facilities, meeting RoHS Directive 2011/65/EU (Pb-free matte tin plating) and REACH SVHC thresholds. It carries MSL Level 1 rating per J-STD-020 and is qualified to JESD22-B102 E3 for solderability - confirmed in DS1251 Rev 15 (July 2023).
SMAJ8.5CA-TR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Package/Case:
- DO-214AC, SMA
- Series:
- SMAJ, TRANSIL™
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 8.5V
- Voltage - Breakdown (Min):
- 9.4V
- Voltage - Clamping (Max) @ Ipp:
- 19.5V
- Current - Peak Pulse (10/1000µs):
- 124A (8/20µs)
- 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)
SMAJ8.5CA-TR FAQ
1.How can I place an order for SMAJ8.5CA-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ8.5CA-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 SMAJ8.5CA-TR reliable?
The price and inventory of SMAJ8.5CA-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ8.5CA-TR is usually 5 days.
3.What payment methods are accepted for SMAJ8.5CA-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ8.5CA-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ8.5CA-TR?
SMAJ8.5CA-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ8.5CA-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 SMAJ8.5CA-TR?
For technical support, including SMAJ8.5CA-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ8.5CA-TR requirements.
6.How does Aetrix verify that SMAJ8.5CA-TR is sourced from the original manufacturer or authorized distributors?
All SMAJ8.5CA-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 SMAJ8.5CA-TR meets industry standards.
7.What is the process for return or replacement of SMAJ8.5CA-TR?
All SMAJ8.5CA-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ8.5CA-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 SMAJ8.5CA-TR part is unused and in its original packaging.
Return procedure for SMAJ8.5CA-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ8.5CA-TR Tags
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