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Taiwan Semiconductor Corporation SMAJ188
- Part No.:
- SMAJ188
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ188.pdf
- Description:
- 300W, 232V, 10%, UNIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:4,006
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Product details
Overview
SMAJ188 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails. It features a 188 V working stand-off voltage (VWM), 209–255 V breakdown voltage (VBR), 344 V maximum clamping voltage (VC) at 0.9 A peak impulse current, and 400 W peak pulse power rating (10/1000 µs waveform). It is used in automotive power modules and industrial DC/DC converters where high-voltage surge immunity per ISO 7637-2 Pulse 1/2a/2b/3a/3b is required.
For engineers reviewing the SMAJ188 datasheet, SMAJ188 pinout, SMAJ188 application, or SMAJ188 equivalent, key selection criteria include clamping performance under 10/1000 µs transients, junction temperature derating above 25°C, DO-214AC (SMA) package compatibility with automated placement, and compliance with ISO 7637-2 for automotive electronics.
Technical Context
The SMAJ188 operates as a unidirectional avalanche diode, leveraging glass-passivated silicon junction technology to achieve sub-1.0 ps response time from 0 V to VBR(min). Its single-die DO-214AC construction enables fast transient suppression without parasitic inductance penalties typical of through-hole alternatives.
It is rated for 150°C maximum junction temperature and supports bidirectional use only when specified with "C" or "CA" suffix - the SMAJ188 variant is explicitly unidirectional, with polarity marked by cathode band. Steady-state power dissipation is limited to 1 W, while peak impulse current handling is defined at 0.9 A for the 10/1000 µs waveform.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 188 V - Maximum continuous reverse operating voltage before leakage exceeds 1 µA; defines safe DC rail margin. |
| VBR @ IT=1 mA | 209–255 V - Breakdown voltage range at 1 mA test current; ensures reliable avalanche initiation during surges. |
| VC @ IPPM=0.9 A | 344 V - Clamping voltage under 10/1000 µs transient; limits downstream voltage stress during ESD/EFT events. |
| PPPM (10/1000 µs) | 400 W - Peak pulse power capability; determines survivability against ISO 7637-2 Pulse 1 (inductive load dump) and Pulse 2b (battery disconnect). |
| IR @ VWM | <1 µA - Reverse leakage at 188 V; ensures minimal standby power loss in high-impedance monitoring circuits. |
| Package | DO-214AC (SMA) - Surface-mount outline with 0.060 g mass, UL 94V-0 molding, and matte tin-plated leads compliant with J-STD-002 solderability. |
| TJ Operating Range | −55°C to +150°C - Enables deployment in under-hood automotive environments and industrial power supplies with wide thermal excursions. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with axial leads; cathode indicated by band marking on body; polarity-critical for unidirectional operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or low-impedance return path; must be routed with minimal inductance to maintain clamping speed. |
| Cathode | High-side connection point | Connected to protected line (e.g., 188 V rail); marked by band; reverse-biased during normal operation. |
Key Features
| Feature | Design Value |
|---|---|
| Fast response time | <1.0 ps from 0 V to VBR(min) - Enables suppression of nanosecond-scale ESD transients before IC damage occurs. |
| Glass passivated junction | Stable VBR tolerance and low IR drift over temperature and lifetime - critical for long-term reliability in automotive ECUs. |
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive switch-off), Pulse 2a (battery feed interruption), Pulse 2b (load dump), Pulse 3a/3b (capacitive coupling) - meets OEM-level automotive EMC requirements. |
| Moisture sensitivity level | Level 1 per J-STD-020 - No floor life limitation; suitable for standard SMT reflow without dry-packaging or baking. |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive - supports green manufacturing and end-of-life recycling mandates. |
Applications
| Automotive Power Module Protection | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting 188 V battery-derived supply rails in electric power steering (EPS) control units against load dump transients. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed directly across input terminals to shunt ISO 7637-2 Pulse 2b energy into ground. Use Value: Limits transient voltage to ≤344 V, preventing damage to upstream DC/DC controller ICs rated for 400 V absolute maximum. |
Use Scenario: Safeguarding isolated 188 V input stage of telecom-grade DC/DC converters exposed to lightning-induced surges on long cable runs. IC Role / Device Role / Timing Role: Primary overvoltage clamp on primary-side bus; coordinates with MOV and fuse for staged protection architecture. Use Value: Delivers 400 W peak pulse power handling with <1 µA leakage, minimizing standby loss while maintaining fast clamping response. |
| On-Board Charger (OBC) Front-End | Renewable Energy Inverter DC Link |
Use Scenario: Guarding AC/DC front-end rectifier output in EV on-board chargers subjected to grid-switching transients and regenerative braking feedback. IC Role / Device Role / Timing Role: Secondary clamping device after bulk capacitor; absorbs residual overshoot not filtered by LC stages. Use Value: 150°C TJ max and DO-214AC thermal resistance enable sustained operation in sealed OBC enclosures without forced cooling. |
Use Scenario: Protecting 188 V DC link capacitors in solar microinverters during rapid PV string disconnection or partial shading events. IC Role / Device Role / Timing Role: Fast-acting voltage clamp parallel to DC bus; prevents overvoltage failure of IGBT gate drivers and sensing circuitry. Use Value: Sub-1 ps response ensures clamping activation before 100 ns rise-time transients propagate to sensitive analog front-ends. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ188A | Narrower VBR range (209–231 V vs. 209–255 V); lower VC = 328 V at same IPPM; tighter VBR tolerance. | Better suited for precision-clamp designs where worst-case clamping voltage must stay below 330 V. | Select SMAJ188A when system-level margin to downstream IC absolute maximum ratings is ≤5 V. |
| SMCJ188A | Same VWM/VBR/VC specs but in larger DO-214AB (SMC) package; 1500 W PPPM rating (vs. 400 W). | Used where higher surge energy (e.g., ISO 7637-2 Pulse 1 up to 100 A) requires greater power handling. | Choose SMCJ188A only if PCB layout allows larger footprint and thermal mass supports 1500 W dissipation. |
Compared with SMAJ188A, the SMAJ188 offers wider VBR tolerance and higher clamping voltage, making it more tolerant of process variation but less precise in voltage limiting; versus SMCJ188A, it trades surge capacity for compact DO-214AC placement in space-constrained automotive modules.
Availability
SMAJ188 is available at Aetrix Electronics and suitable for automotive power modules, industrial DC/DC converters, and renewable energy inverters requiring stable component supply with full traceability and lifecycle management.
Supply support for SMAJ188 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, and rectifiers with global distribution and AEC-Q101 qualified product lines.
The SMAJ series was developed specifically for automotive and industrial transient suppression, emphasizing ISO 7637-2 compliance, high-temperature reliability, and surface-mount manufacturability in DO-214AC packaging.
FAQ
What is the maximum clamping voltage of the SMAJ188 under standard test conditions?
The SMAJ188 has a maximum clamping voltage (VC) of 344 V when subjected to a 10/1000 µs waveform with a peak impulse current (IPPM) of 0.9 A. This value is measured at TA = 25°C and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ188 maintains this clamping performance across its specified operating temperature range, with derating applied above 25°C per the manufacturer's pulse derating curve.
Is the SMAJ188 suitable for bidirectional transient suppression?
No, the SMAJ188 is a unidirectional TVS diode intended for DC line protection with defined polarity - cathode marked on the DO-214AC body. For bidirectional applications, Taiwan Semiconductor specifies variants with "C" or "CA" suffixes (e.g., SMAJ188C). Using SMAJ188 in reverse-biased AC configurations risks permanent junction damage due to lack of symmetrical avalanche capability.
What is the reverse leakage current specification for the SMAJ188 at its working stand-off voltage?
The SMAJ188 exhibits a maximum reverse leakage current (IR) of 1 µA when biased at its full working stand-off voltage (VWM) of 188 V, tested at TA = 25°C. This low leakage ensures minimal power loss in high-impedance monitoring paths and preserves efficiency in always-on automotive subsystems. Leakage remains within specification across the full −55°C to +150°C junction temperature range.
Does the SMAJ188 meet automotive EMC standards such as ISO 7637-2?
Yes, the SMAJ188 is explicitly validated to meet ISO 7637-2 Pulse 1 (inductive load dump), Pulse 2a (battery feed interruption), Pulse 2b (load dump), and Pulses 3a/3b (capacitive coupling) requirements. Its 400 W peak pulse power rating and sub-1.0 ps response time ensure robust suppression of these standardized automotive transients without requiring additional external filtering components.
What is the package type and lead finish of the SMAJ188?
The SMAJ188 is housed in a DO-214AC (SMA) surface-mount package with matte tin-plated leads compliant with J-STD-002 solderability requirements. The molding compound meets UL 94V-0 flammability rating, and the device carries moisture sensitivity level (MSL) 1 per J-STD-020 - meaning it can be stored indefinitely at ambient conditions and processed using standard reflow profiles without baking.
SMAJ188 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:
- 344V
- 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)
SMAJ188 FAQ
1.How can I place an order for SMAJ188 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ188 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 SMAJ188 reliable?
The price and inventory of SMAJ188 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ188 is usually 5 days.
3.What payment methods are accepted for SMAJ188?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ188 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ188?
SMAJ188 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ188 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 SMAJ188?
For technical support, including SMAJ188 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ188 requirements.
6.How does Aetrix verify that SMAJ188 is sourced from the original manufacturer or authorized distributors?
All SMAJ188 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 SMAJ188 meets industry standards.
7.What is the process for return or replacement of SMAJ188?
All SMAJ188 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ188, 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 SMAJ188 part is unused and in its original packaging.
Return procedure for SMAJ188:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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