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Taiwan Semiconductor Corporation SMAJ170CA
- Part No.:
- SMAJ170CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ170CA.pdf
- Description:
- TVS DIODE 170VWM 275VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,533
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Product details
Overview
SMAJ170CA 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 170 V working stand-off voltage (VWM), 189–231 V breakdown voltage (VBR @ 1 mA), 304 V maximum clamping voltage (VC @ 1 A), 400 W peak pulse power (10/1000 µs), and operates across –55 °C to +150 °C junction temperature range - deployed in automotive DC/DC converters and industrial SMPS inputs.
For engineers reviewing the SMAJ170CA datasheet, SMAJ170CA pinout, SMAJ170CA application, or SMAJ170CA equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b transients, bidirectional surge handling capability, low leakage (<1 µA at 170 V), and compatibility with automated SMT placement on high-reliability power supply boards.
Technical Context
The SMAJ170CA implements a glass-passivated silicon avalanche junction optimized for fast transient suppression. Its bidirectional configuration enables symmetrical clamping in both polarities without external polarity management, supporting compliance with ISO 7637-2 Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling noise).
It delivers sub-nanosecond response time (<1.0 ps from 0 V to VBR min) and maintains <1 µA reverse leakage at rated VWM, ensuring minimal standby power loss in always-on systems. The device is rated for 400 W peak pulse power at 25 °C, derated linearly above ambient per Fig.2, and supports 40 A non-repetitive forward surge current (8.3 ms half-sine).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 170 V - Maximum continuous DC or RMS voltage the device blocks without clamping |
| VBR @ IT=1 mA | 189–231 V - Breakdown threshold range where avalanche conduction begins reliably |
| VC @ IPPM=1 A | 304 V - Maximum voltage seen across protected circuit during 1 A 10/1000 µs transient |
| PPPM | 400 W - Peak surge power dissipation capability under standard 10/1000 µs waveform |
| IR @ VWM | <1 µA - Negligible leakage current at operating voltage, critical for low-power standby circuits |
| Junction Temp Range | –55 °C to +150 °C - Enables deployment in under-hood automotive and industrial environments |
| Package | DO-214AC (SMA) - Standard surface-mount outline compatible with IPC-7351B footprint and J-STD-002 solderability |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band (bidirectional operation means band denotes common terminal; terminals are symmetrical and interchangeable).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Transient current path | Both terminals serve identical roles in bidirectional clamping; no polarity sensitivity in layout |
| Cathode band marking | Reference orientation | Provides visual alignment aid during placement; does not imply unidirectional function for SMAJ170CA |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR tolerance and long-term reliability under thermal cycling and humidity stress |
| ISO 7637-2 compliance | Validated for automotive load-dump (Pulse 1), line-switching (Pulse 2a/2b), and ESD-coupled (Pulse 3a/3b) immunity |
| Moisture sensitivity level 1 | Zero bake requirement before reflow; compatible with standard SMT assembly without dry-pack handling |
| Halogen-free & RoHS | Meets IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally constrained applications |
| Fast response & low clamping | <1.0 ps turn-on ensures protection before downstream ICs experience overstress; 304 V clamp limits voltage overshoot |
Applications
| Automotive DC/DC Converter Input | Industrial SMPS Front-End |
|---|---|
Use Scenario: Protection of 24 V/48 V input stage against load dump and battery reversal transients in vehicle-mounted DC/DC modules. IC Role / Device Role / Timing Role: Bidirectional TVS placed directly at connector entry point to shunt surge energy before upstream filtering. Use Value: Withstands 400 W pulses and clamps to ≤304 V, preventing damage to buck controller ICs and MOSFETs rated for 350 V max. | Use Scenario: Surge suppression on AC-DC rectified bus feeding isolated flyback or LLC converters in factory automation equipment. IC Role / Device Role / Timing Role: Primary-level transient limiter absorbing line-induced spikes (e.g., contactor switching, lightning-induced surges). Use Value: 170 V VWM allows safe operation across 120–277 VAC-derived rails; <1 µA leakage avoids efficiency penalty in standby mode. |
| LED Driver Power Input | On-Board Telecom DC Distribution |
Use Scenario: Input protection for constant-current LED drivers used in street lighting and tunnel illumination exposed to outdoor electrical disturbances. IC Role / Device Role / Timing Role: First-line defense against induced surges from nearby lightning strikes or grid switching events. Use Value: 304 V clamping voltage ensures driver ICs (typically rated 350–400 V) remain within safe operating area during 1 kV/2 kA transients. | Use Scenario: Point-of-load protection on 48 V telecom backplane distribution networks powering remote radio units and baseband processors. IC Role / Device Role / Timing Role: Localized TVS at board edge to suppress coupled noise from hot-swap events and relay bounce. Use Value: DO-214AC footprint enables dense placement near connectors; bidirectional symmetry eliminates layout polarity errors during high-volume manufacturing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ170CA | Identical electrical specs, same DO-214AC package, identical ISO 7637-2 compliance; minor differences in IR test condition (Littelfuse specifies <1 µA @ VWM, TSC specifies <1 µA @ 170 V) | No functional difference; validated in same automotive and industrial reference designs | Select based on distributor lead time and traceability requirements |
| Vishay SMAJ170CA-E3/5AT | Same VWM/VC/PPPM; Vishay version includes enhanced moisture resistance (MSL 1 per J-STD-020) and tighter VBR tolerance (±5% vs ±10% typical for TSC) | Better suited for high-humidity deployments (e.g., outdoor telecom enclosures); tighter VBR improves design margin predictability | Prefer for humidity-critical applications or when tighter parametric control is required |
Compared with Littelfuse and Vishay alternatives, the Taiwan Semiconductor SMAJ170CA offers identical core protection performance and footprint compatibility but with broader VBR tolerance and optimized cost structure for high-volume industrial power supplies.
Availability
SMAJ170CA is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial SMPS front-ends, and LED driver power inputs requiring stable component supply across extended temperature and surge conditions.
Supply support for SMAJ170CA 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 Company (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in TVS diodes, rectifiers, and power MOSFETs since 1979.
The SMAJ series was developed specifically for high-energy transient suppression in automotive and industrial power systems, emphasizing ISO 7637-2 compliance, MSL-1 reliability, and SMT manufacturability.
FAQ
What is the clamping voltage of SMAJ170CA at its rated peak pulse current?
The SMAJ170CA has a maximum clamping voltage (VC) of 304 V when subjected to its rated peak pulse current of 1 A under the standard 10/1000 µs waveform. This value is measured per JEDEC test conditions and guarantees that downstream components see no more than 304 V during surge events - a critical parameter for protecting 350 V-rated MOSFETs and controllers in 48 V systems. The SMAJ170CA achieves this while maintaining low leakage and fast response.
Is SMAJ170CA unidirectional or bidirectional, and how does that affect PCB layout?
SMAJ170CA is a bidirectional TVS diode, indicated by the "CA" suffix per Taiwan Semiconductor's naming convention. Unlike unidirectional variants (e.g., SMAJ170A), it provides symmetrical clamping in both polarities - meaning either terminal can connect to the protected line without regard to polarity. This eliminates orientation constraints during SMT placement and simplifies layout for AC-coupled or floating-rail applications. The cathode band serves only as a mechanical alignment marker, not a polarity indicator, for the SMAJ170CA.
Does SMAJ170CA meet automotive transient immunity standards?
Yes, SMAJ170CA meets ISO 7637-2 Pulse 1 (load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) requirements as verified in Taiwan Semiconductor's characterization data. Its 400 W peak pulse power rating, 304 V clamping voltage, and sub-nanosecond response ensure robust protection for 24 V and 48 V automotive subsystems. The SMAJ170CA is widely deployed in body control modules, infotainment power supplies, and ADAS camera DC/DC stages where compliance with OEM-level surge testing is mandatory.
What is the maximum operating temperature and thermal derating behavior of SMAJ170CA?
The SMAJ170CA has a maximum junction temperature (TJ) of +150 °C and operates from –55 °C to +150 °C. Its peak pulse power rating of 400 W is specified at TA = 25 °C and derates linearly above that ambient, per Figure 2 in the datasheet - approximately 3.33 W/°C reduction from 25 °C to 150 °C. At 100 °C ambient, the usable PPPM drops to ~140 W. This derating curve must be applied in thermally constrained enclosures, and the SMAJ170CA's DO-214AC package supports adequate heat spreading via copper pour under the cathode/anode pads.
How does SMAJ170CA compare to SMAJ170A in terms of electrical performance?
SMAJ170CA is bidirectional, while SMAJ170A is unidirectional. Their key electrical parameters differ: SMAJ170CA has VBR = 189–231 V (bidirectional), VC = 304 V, and IR < 1 µA at 170 V; SMAJ170A shares the same VWM and VC but exhibits forward conduction below –170 V only. For AC or floating-rail protection, SMAJ170CA eliminates need for dual-diode configurations. The SMAJ170CA also has identical 400 W rating and DO-214AC footprint, enabling drop-in replacement where bidirectional clamping is required.
SMAJ170CA 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):
- 170V
- Voltage - Breakdown (Min):
- 189V
- Voltage - Clamping (Max) @ Ipp:
- 275V
- Current - Peak Pulse (10/1000µs):
- 1.1A
- 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)
SMAJ170CA FAQ
1.How can I place an order for SMAJ170CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ170CA 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 SMAJ170CA reliable?
The price and inventory of SMAJ170CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ170CA is usually 5 days.
3.What payment methods are accepted for SMAJ170CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ170CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ170CA?
SMAJ170CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ170CA 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 SMAJ170CA?
For technical support, including SMAJ170CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ170CA requirements.
6.How does Aetrix verify that SMAJ170CA is sourced from the original manufacturer or authorized distributors?
All SMAJ170CA 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 SMAJ170CA meets industry standards.
7.What is the process for return or replacement of SMAJ170CA?
All SMAJ170CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ170CA, 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 SMAJ170CA part is unused and in its original packaging.
Return procedure for SMAJ170CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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