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Taiwan Semiconductor Corporation SMAJ188A
- Part No.:
- SMAJ188A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ188A.pdf
- Description:
- TVS DIODE 188VWM 328VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:6,340
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Product details
Overview
SMAJ188A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for overvoltage protection in DC power lines and signal paths. It features a 188 V working stand-off voltage (VWM), 209–231 V breakdown voltage (VBR), 328 V maximum clamping voltage (VC) at 0.9 A peak impulse current, and 400 W peak pulse power rating with 10/1000 µs waveform - suitable for automotive load-dump and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance.
For engineers reviewing the SMAJ188A datasheet, SMAJ188A pinout, SMAJ188A application, or SMAJ188A equivalent, key selection criteria include clamping performance under 10/1000 µs transients, junction temperature derating above 25°C, unidirectional polarity marking, DO-214AC (SMA) package compatibility with automated placement, and leakage current ≤1 µA at 188 V.
Technical Context
The SMAJ188A operates as a silicon avalanche diode, leveraging glass-passivated junction technology to achieve fast response (<1.0 ps from 0 V to VBR min) and stable clamping during ESD and surge events. Its unidirectional configuration provides reverse-biased overvoltage clamping while blocking forward conduction beyond VF = 3.5 V at 25 A.
Thermal design requires adherence to TJ max = 150°C with derating per Fig.2; steady-state power dissipation is limited to 1 W, and peak surge capability is defined for non-repetitive 10/1000 µs pulses up to 400 W - reduced to 300 W for devices rated above 78 V per specification note.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 188 V - maximum continuous reverse operating voltage before clamping initiates |
| VBR min/max | 209–231 V @ IT = 1 mA - ensures reliable avalanche turn-on within specified tolerance band |
| VC @ IPPM | 328 V @ 0.9 A - clamping voltage limits protected circuit stress during 10/1000 µs surge |
| PPPM | 400 W (10/1000 µs) - peak transient energy absorption capacity at TA = 25°C |
| IR @ VWM | ≤1 µA - minimal leakage preserves efficiency in high-impedance bias networks |
| TJ range | −55°C to +150°C - supports operation in under-hood automotive and industrial ambient environments |
| Package | DO-214AC (SMA) - industry-standard surface-mount outline compatible with J-STD-002 soldering |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, cathode band marking for unidirectional polarity, 0.060 g mass, UL 94V-0 flammability rating, and JESD201 Class 2 whisker resistance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connects to lower-potential side of protected line; conducts only during forward surge or bias |
| Cathode | Clamping terminal (marked band) | Connected to higher-potential rail; avalanche breakdown occurs between cathode and anode during reverse overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures long-term stability and low parameter drift under thermal cycling and humidity exposure |
| Fast response time <1.0 ps | Enables suppression of nanosecond-scale ESD events before downstream ICs experience overstress |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validates suitability for 12 V and 24 V automotive power net protection without external filtering |
| Moisture sensitivity level 1 | Permits unlimited floor life and standard SMT reflow without baking preconditioning |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU Directive 2011/65/EU for environmentally constrained applications |
Applications
| Automotive Power Distribution | Industrial DC/DC Converters |
|---|---|
Use Scenario: Protection of 24 V battery-fed ECUs against load dump transients up to ±120 V. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed across input terminals to clamp surges before they reach DC/DC controller ICs. Use Value: Clamps to 328 V at 0.9 A, limiting stress on 40 V-rated input capacitors and MOSFETs in buck controllers. | Use Scenario: Input-side surge suppression in isolated 48 V-to-12 V telecom DC/DC modules. IC Role / Device Role / Timing Role: Standoff-rated TVS absorbing repetitive switching noise and lightning-induced surges on primary-side bus. Use Value: 400 W peak power rating sustains multiple 10/1000 µs events without degradation, supporting EN 61000-4-5 Level 3 immunity. |
| LED Driver Power Inputs | Smart Meter Power Supplies |
Use Scenario: Overvoltage protection for constant-current LED drivers powered from unregulated AC/DC adapters. IC Role / Device Role / Timing Role: Primary-line TVS absorbing adapter output overshoot and hot-plug transients. Use Value: 188 V VWM matches typical 170–190 VDC adapter outputs, enabling margin before clamping activation. | Use Scenario: Front-end protection in polyphase smart meters exposed to utility grid surges. IC Role / Device Role / Timing Role: Unidirectional clamping device on meter's auxiliary supply input (e.g., 12 V derived from mains). Use Value: 150°C max junction temperature enables operation inside sealed, thermally constrained meter enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ188 | Higher VBR (209–255 V) and VC (344 V); same VWM and package | Less tight clamping margin - may allow higher stress on downstream components during worst-case surge | Select SMAJ188A when tighter clamping control and lower VC are required for sensitive 300 V-rated inputs |
| SMBJ188A | Same electrical specs but SMB (DO-214AA) package - 2.5 mm wider body, higher thermal mass | Lower power density; better thermal dissipation but requires larger PCB footprint | Choose SMBJ188A where board space permits and enhanced thermal robustness is prioritized over miniaturization |
Compared with SMAJ188 and SMBJ188A, the SMAJ188A offers the tightest clamping voltage (328 V) in the smallest DO-214AC footprint, making it optimal for space-constrained automotive and industrial power rails requiring precise overvoltage limiting.
Availability
SMAJ188A is available at Aetrix Electronics and suitable for automotive power distribution, industrial DC/DC converters, and LED driver power inputs requiring stable component supply, full traceability, and lifecycle continuity.
Supply support for SMAJ188A 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 product line, engineered specifically for robust, standards-compliant overvoltage protection in automotive, industrial, and consumer power systems with stringent reliability and environmental requirements.
FAQ
What is the clamping voltage of the SMAJ188A under a 10/1000 µs surge?
The SMAJ188A has a maximum clamping voltage (VC) of 328 V when subjected to its rated peak impulse current of 0.9 A with a 10/1000 µs waveform. This value is measured per Fig.5 in the official datasheet and defines the upper voltage limit imposed on protected circuits during standardized surge events.
Is the SMAJ188A suitable for bidirectional surge protection?
No - the SMAJ188A is a unidirectional TVS diode, indicated by the absence of "C" or "CA" suffix and confirmed by its single cathode band marking. For bidirectional protection, select SMAJ188CA, which provides symmetrical clamping in both polarities and meets identical peak power ratings.
What is the maximum junction temperature rating for the SMAJ188A?
The SMAJ188A has a maximum operating junction temperature (TJ max) of +150°C, with derating applied above TA = 25°C per the pulse derating curve (Fig.2). This allows reliable operation in under-hood automotive and enclosed industrial environments where ambient temperatures exceed 100°C.
Does the SMAJ188A meet automotive EMC standards?
Yes - the SMAJ188A is explicitly rated to meet ISO 7637-2 test pulses 1, 2a, 2b, 3a, and 3b, covering common conducted transient threats in 12 V and 24 V vehicle electrical systems. Its 400 W peak pulse power and fast response make it suitable for front-end protection in ECUs and body control modules.
What packaging and reel quantity is offered for the SMAJ188A?
The SMAJ188A is supplied in DO-214AC (SMA) package format on tape-and-reel, with 7,500 units per reel. The package features matte tin-plated leads compliant with J-STD-002 solderability requirements and moisture sensitivity level 1 per J-STD-020 - no bake preconditioning required prior to SMT assembly.
SMAJ188A 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):
- 188V
- Voltage - Breakdown (Min):
- 209V
- Voltage - Clamping (Max) @ Ipp:
- 328V
- Current - Peak Pulse (10/1000µs):
- 900mA
- 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)
SMAJ188A FAQ
1.How can I place an order for SMAJ188A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ188A 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 SMAJ188A reliable?
The price and inventory of SMAJ188A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ188A is usually 5 days.
3.What payment methods are accepted for SMAJ188A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ188A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ188A?
SMAJ188A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ188A 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 SMAJ188A?
For technical support, including SMAJ188A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ188A requirements.
6.How does Aetrix verify that SMAJ188A is sourced from the original manufacturer or authorized distributors?
All SMAJ188A 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 SMAJ188A meets industry standards.
7.What is the process for return or replacement of SMAJ188A?
All SMAJ188A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ188A, 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 SMAJ188A part is unused and in its original packaging.
Return procedure for SMAJ188A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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