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STMicroelectronics SMAJ170A-TR
- Part No.:
- SMAJ170A-TR
- Manufacturer:
- STMicroelectronics
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ170A-TR.pdf
- Description:
- TVS DIODE 170VWM 353VC SMA
- Quantity:
- Payment:
- Shipping:
Inventory:7,565
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Product details
Overview
SMAJ170A-TR from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for primary-level surge protection in DC power lines and signal interfaces. It delivers 400 W peak pulse power (10/1000 μs), clamps transients to 275 V at 1.4 A, and operates up to 150 °C junction temperature-enabling robust protection in industrial power supplies and telecom infrastructure.
For engineers reviewing the SMAJ170A-TR datasheet, SMAJ170A-TR pinout, SMAJ170A-TR application, or SMAJ170A-TR equivalent, key selection criteria include standoff voltage (170 V), clamping voltage (275 V @ 1.4 A), low leakage (0.2 µA @ 25 °C), JEDEC DO-214AC (SMA) package compatibility, and IEC 61000-4-2/4-4 compliance.
Technical Context
This TVS diode uses planar silicon technology to achieve stable breakdown characteristics and low leakage across its operating temperature range (−55 °C to +150 °C). Its unidirectional configuration provides asymmetric clamping-forward conduction during positive overvoltage events and reverse-biased blocking during normal operation.
The device meets IEC 61000-4-2 level 4 (30 kV air/contact discharge) and IEC 61000-4-4 level 4 (4 kV), with dynamic resistance of 22.2 Ω at 8/20 μs surges. Its thermal impedance (junction-to-ambient) is optimized for standard FR4 PCB footprints per IPC-7531.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Standoff Voltage (VRM) | 170 V - Maximum continuous reverse working voltage before clamping initiates |
| Breakdown Voltage (VBR) | 189–199 V @ 1 mA - Ensures reliable triggering above nominal line voltage with margin |
| Clamping Voltage (VCL) | 275 V @ 1.4 A (10/1000 μs) - Limits downstream voltage stress during surge events |
| Peak Pulse Power | 400 W (10/1000 μs) - Sustains common lightning-induced surges in industrial DC rails |
| Leakage Current | 0.2 µA @ 25 °C - Minimizes standby power loss in high-impedance sensing circuits |
| Junction Temperature | −55 °C to +150 °C - Supports operation in enclosed enclosures without forced cooling |
| Package | DO-214AC (SMA) - Standard surface-mount footprint compatible with automated assembly |
Pinout & Package
Package: DO-214AC (SMA), JEDEC-registered outline per IPC-7531, with matte tin-plated leads compliant with J-STD-002 and JESD 22-B102 E3.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Cathode (marked band) | Surge current sink | Connected to protected line; conducts during overvoltage to shunt energy to ground |
| Anode | Reference node | Tied to system ground or return path; completes clamping loop during transient |
Key Features
| Feature | Design Value |
|---|---|
| Low leakage current | 0.2 µA at 25 °C enables use in battery-backed or ultra-low-power monitoring circuits |
| High-temperature operation | Rated to +150 °C junction ensures reliability in thermally constrained enclosures |
| IEC 61000-4-2/4-4 compliance | Validated to level 4 (30 kV ESD, 4 kV EFT) for industrial-grade immunity certification |
| Planar silicon construction | Delivers consistent VBR tolerance and long-term stability under repeated surge stress |
Applications
| Industrial Power Supply Input Protection | Telecom DC Feeder Line Protection |
|---|---|
Use Scenario: 24–48 V DC input stage of programmable logic controllers (PLCs) exposed to load dump and inductive switching transients. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between input rail and chassis ground to clamp fast-rising surges before they reach upstream regulators. Use Value: Clamps 1.4 A transients to ≤275 V, preventing damage to 300 V-rated input capacitors and MOSFET front-end switches. | Use Scenario: −48 V DC power feeders in central office equipment subject to lightning-induced longitudinal surges. IC Role / Device Role / Timing Role: Primary surge suppressor on each feeder line, mounted adjacent to connector entry point. Use Value: Withstands 400 W (10/1000 μs) surges while maintaining <0.2 µA leakage-critical for low-noise bias networks. |
| Automotive Body Control Module (BCM) Power Rail | Smart Meter DC Auxiliary Supply Protection |
Use Scenario: 12 V auxiliary supply input in BCMs subjected to ISO 7637-2 pulse 1/2a/3a and load dump. IC Role / Device Role / Timing Role: Secondary-level TVS on fused 12 V rail, downstream of main fuse but upstream of LDOs and microcontrollers. Use Value: Operates reliably at 150 °C junction temperature, surviving under-hood thermal cycling without parameter drift. | Use Scenario: 5 V or 3.3 V auxiliary supply derived from AC/DC converter in utility smart meters. IC Role / Device Role / Timing Role: Final-stage transient guard before metering ICs and real-time clock circuitry. Use Value: Low 0.2 µA leakage preserves accuracy of high-impedance voltage dividers used in precision metering references. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar unidirectional TVS diode applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMBJ170A-TR | Same VRWM (170 V), higher PPP (600 W), larger SMB package (DO-214AA) | Requires more PCB area; better suited for higher-energy surges where space permits | Select when surge energy exceeds 400 W and board layout allows SMB footprint |
| SMCJ170A-TR | Same VRWM, PPP = 1500 W, DO-214AB (SMC) package | Designed for mains-connected equipment with higher IEC 61000-4-5 requirements | Choose for AC/DC front-end protection where 1.5 kW pulse handling is mandated |
Compared with SMBJ170A-TR and SMCJ170A-TR, the SMAJ170A-TR offers optimal balance of compact DO-214AC size, 400 W capability, and low leakage-ideal for space-constrained DC rails where moderate surge energy must be managed without sacrificing thermal or leakage performance.
Availability
SMAJ170A-TR is available at Aetrix Electronics and suitable for industrial power supplies, telecom DC feeders, automotive body control modules, and smart meter auxiliary supplies requiring stable component supply and full traceability.
Supply support for SMAJ170A-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, specializing in power management, analog, MEMS, and microcontroller technologies.
The SMAJ series belongs to ST's transient protection portfolio, engineered specifically for cost-effective, high-reliability DC line protection in industrial, telecom, and automotive systems where compact size and thermal resilience are critical.
FAQ
What is the maximum clamping voltage of SMAJ170A-TR under a 10/1000 μs surge?
The maximum clamping voltage (VCL) is 275 V at 1.4 A for a 10/1000 μs waveform, measured at Tamb = 25 °C. This value increases with junction temperature per the αT coefficient (10.8 × 10−4/°C), reaching ~285 V at 125 °C junction temperature.
Is SMAJ170A-TR bidirectional or unidirectional?
SMAJ170A-TR is unidirectional: it functions as a reverse-biased Zener-like clamp for positive transients on the cathode side, with forward conduction only during overvoltage events. The "A" suffix explicitly denotes unidirectional configuration, distinct from "CA" bidirectional variants.
Does SMAJ170A-TR meet RoHS and REACH requirements?
Yes-SMAJ170A-TR is manufactured in ST's ECOPACK2-compliant facilities, meeting RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006. Lead finish is matte tin, and halogen-free packaging is standard per ST's environmental policy.
Can SMAJ170A-TR be used in parallel for higher surge current handling?
No-parallel connection is not recommended due to mismatch in dynamic resistance (RD = 22.2 Ω) and VBR tolerance, which causes uneven current sharing and potential thermal runaway. For higher current, select a single higher-power device like SMCJ170A-TR instead.
SMAJ170A-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:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 170V
- Voltage - Breakdown (Min):
- 189V
- Voltage - Clamping (Max) @ Ipp:
- 353V
- Current - Peak Pulse (10/1000µs):
- 6.5A (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)
SMAJ170A-TR FAQ
1.How can I place an order for SMAJ170A-TR through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ170A-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 SMAJ170A-TR reliable?
The price and inventory of SMAJ170A-TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ170A-TR is usually 5 days.
3.What payment methods are accepted for SMAJ170A-TR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ170A-TR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ170A-TR?
SMAJ170A-TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ170A-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 SMAJ170A-TR?
For technical support, including SMAJ170A-TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ170A-TR requirements.
6.How does Aetrix verify that SMAJ170A-TR is sourced from the original manufacturer or authorized distributors?
All SMAJ170A-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 SMAJ170A-TR meets industry standards.
7.What is the process for return or replacement of SMAJ170A-TR?
All SMAJ170A-TR units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ170A-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 SMAJ170A-TR part is unused and in its original packaging.
Return procedure for SMAJ170A-TR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ170A-TR Tags
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