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Taiwan Semiconductor Corporation SMAJ188H
- Part No.:
- SMAJ188H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ188H.pdf
- Description:
- TVS DIODE 188VWM 344VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,762
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Product details
Overview
SMAJ188H from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for high-energy surge protection in DC power lines and signal interfaces. 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 AEC-Q101 qualified and used in automotive on-board DC/DC converters to protect sensitive control ICs from ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ188H datasheet, SMAJ188H pinout, SMAJ188H application, or SMAJ188H equivalent, key selection criteria include its 188 V VWM rating, DO-214AC (SMA) package compatibility with automated placement, bidirectional-capable variant options (SMAJ188AH), and compliance with automotive-grade reliability standards including JESD201 Class 2 whisker resistance and moisture sensitivity level 1.
Technical Context
The SMAJ188H operates as a unidirectional avalanche diode with glass-passivated junction, enabling fast response (<1.0 ps from 0 V to VBR min) and low leakage (<1 µA at VWM). Its clamping behavior is defined by a 10/1000 µs double-exponential surge waveform, with peak power derated linearly above 25°C ambient per Fig.2.
It supports single-die configuration in DO-214AC (SMA) package, rated for TJ = –55°C to +150°C operation and 40 A IFSM surge capability. Polarity is marked by cathode band; reverse leakage is specified at 1 µA @ 188 V, and forward voltage is not applicable for unidirectional TVS in reverse-biased protection mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 188 V - Maximum continuous DC or RMS voltage the device blocks without conduction. |
| VBR min/max | 209–255 V @ 1 mA - Ensures reliable avalanche turn-on above system operating voltage with margin against false triggering. |
| VC @ IPPM | 344 V @ 0.9 A - Clamped voltage during 10/1000 µs surge; defines maximum stress imposed on protected downstream circuitry. |
| PPPM | 400 W (10/1000 µs) - Peak surge energy handling capacity; derates above 25°C ambient per published curve. |
| IR @ VWM | <1 µA - Minimal leakage ensures negligible standby power loss and no interference with high-impedance sensing nodes. |
| Package | DO-214AC (SMA) - Standardized surface-mount outline compatible with JEDEC MS-013, supports automated pick-and-place and reflow. |
| AEC-Q101 | Qualified - Validated for automotive underhood and chassis applications per stress test requirements (HTOL, TCT, etc.). |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band on cathode end. Weight ≈ 0.060 g. Meets UL 94V-0 flammability and J-STD-002 solderability standards.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to system ground or low-voltage rail; forms return path during clamping event. |
| Cathode | High-side surge input terminal | Connected to protected line (e.g., 12 V battery rail); avalanche conduction occurs when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive electronics use, including temperature cycling, humidity bias, and high-temperature operating life testing. |
| Glass passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal/humidity stress vs. epoxy-passivated alternatives. |
| Fast response time <1.0 ps | Enables suppression before transient propagates into protected ICs-critical for CAN, LIN, and microcontroller I/O protection. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Meets full suite of automotive transient immunity requirements for 12 V and 24 V systems without external filtering. |
| Moisture sensitivity level 1 | Zero bake requirement prior to reflow; supports standard SMT assembly without special handling or dry pack. |
Applications
| Automotive On-Board DC/DC Converter | Industrial SMPS Input Stage |
|---|---|
Use Scenario: Protects primary-side controller ICs and gate drivers in 12 V → 3.3 V/5 V buck converters subjected to load dump and jump-start transients. IC Role / Device Role: Unidirectional TVS placed between VIN and GND, clamping surges before they reach switching controller and MOSFET gate. Use Value: Limits peak voltage to ≤344 V during 400 W 10/1000 µs pulses, preserving controller reliability and avoiding overvoltage lockout or latch-up. |
Use Scenario: Shields AC-DC adapter output rails and secondary-side regulation circuits from back-fed transients and ESD events. IC Role / Device Role: Standoff-rated TVS on +VOUT/GND node, absorbing repetitive line-induced spikes in DIN-rail mounted power supplies. Use Value: Maintains <1 µA leakage at 188 V, preventing drift in precision feedback networks while delivering 400 W surge immunity. |
| LED Driver Power Input | Telecom DC Feeder Protection |
Use Scenario: Safeguards constant-current LED driver ICs in streetlight and automotive lighting modules exposed to inductive switching noise. IC Role / Device Role: Primary-side transient clamp on HV DC bus (e.g., 170–190 V), coordinated with MOV and fuse for staged protection. Use Value: 188 V VWM aligns with nominal 170–190 V LED string operating range, minimizing false triggering while ensuring clamping below driver IC absolute max ratings. |
Use Scenario: Installed on -48 V telecom DC feeder lines to absorb lightning-induced surges and switching transients before reaching PSE or PD controllers. IC Role / Device Role: Unidirectional TVS on negative rail relative to chassis ground, leveraging cathode-to-rail connection for optimal clamping symmetry. Use Value: 344 V VC ensures protected PHY and PMIC remain within 40 V absolute max rating when referenced to local ground, meeting GR-1089-CORE Level 3. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ188AH | Lower VBR range (209–231 V vs. 209–255 V); tighter tolerance improves consistency in high-volume production. | Preferred where tighter VBR distribution reduces risk of marginal clamping in multi-unit systems. | Select SMAJ188AH when statistical process control of breakdown voltage is required for safety-critical designs. |
| SMBJ188H | Same VWM/VBR/VC specs but in DO-214AA (SMB) package - 2.5 mm wider body, higher thermal mass, 600 W PPPM rating. | Better suited for higher-reliability industrial applications requiring extended surge endurance or higher IFSM (100 A). | Choose SMBJ188H when board space allows larger footprint and system-level surge testing exceeds 400 W requirements. |
Compared with SMAJ188H, SMAJ188AH offers improved VBR consistency at the cost of slightly reduced upper-breakdown margin, while SMBJ188H delivers higher surge robustness in a larger package-neither is pin-compatible, but both share identical electrical function and mounting orientation.
Availability
SMAJ188H is available at Aetrix Electronics and suitable for automotive on-board DC/DC converters, industrial SMPS input stages, and LED driver power inputs requiring stable component supply across multi-year production cycles.
Supply support for SMAJ188H 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, and power MOSFETs for automotive and industrial markets.
The SMAJ series was developed specifically for AEC-Q101-compliant transient protection in space-constrained automotive ECUs and power modules, emphasizing reliability, automated assembly compatibility, and ISO 7637-2 compliance.
FAQ
What is the maximum clamping voltage of the SMAJ188H under standard test conditions?
The SMAJ188H has a maximum clamping voltage (VC) of 344 V when subjected to its rated peak impulse current of 0.9 A using the 10/1000 µs waveform. This value is measured per Fig.5 in the official datasheet and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ188H maintains this clamping performance across its full operating temperature range of –55°C to +150°C.
Is the SMAJ188H suitable for bidirectional transient protection?
No-the SMAJ188H is a unidirectional TVS diode intended for DC line protection with defined anode/cathode polarity. For bidirectional applications such as AC lines or data buses, the SMAJ188H must be paired with another SMAJ188H in inverse parallel, or the bipolar variant SMAJ188AH should be selected instead. The SMAJ188H datasheet explicitly states that electrical characteristics apply only in the reverse direction for unidirectional use.
Does the SMAJ188H meet automotive qualification standards?
Yes-the SMAJ188H is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b transient immunity requirements. It also complies with JESD201 Class 2 whisker resistance, J-STD-020 moisture sensitivity level 1, and RoHS/halogen-free standards per IEC 61249-2-21. These qualifications are verified and documented in Taiwan Semiconductor's official A2102 revision release.
What is the thermal derating behavior of the SMAJ188H above 25°C ambient?
The SMAJ188H peak pulse power (PPPM) is derated linearly above 25°C ambient temperature per Fig.2 in the datasheet: at 75°C TA, PPPM drops to ~280 W; at 125°C TA, it falls to ~120 W. This derating applies to non-repetitive 10/1000 µs pulses and must be factored into thermal design when the device is deployed in high-temperature enclosures or near heat-generating components.
Can the SMAJ188H be used in place of SMAJ180H or SMAJ200H?
No-SMAJ188H is not a direct substitute for SMAJ180H (VWM = 180 V) or SMAJ200H (VWM = 200 V), as its 188 V working stand-off voltage is specifically matched to systems operating near that rail. Substituting would risk premature clamping (if VWM too low) or insufficient protection margin (if VWM too high). Each SMAJxH variant is electrically distinct and must be selected based on exact system VWM and transient margin requirements.
SMAJ188H 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ188H FAQ
1.How can I place an order for SMAJ188H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ188H 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 SMAJ188H reliable?
The price and inventory of SMAJ188H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ188H is usually 5 days.
3.What payment methods are accepted for SMAJ188H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ188H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ188H?
SMAJ188H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ188H 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 SMAJ188H?
For technical support, including SMAJ188H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ188H requirements.
6.How does Aetrix verify that SMAJ188H is sourced from the original manufacturer or authorized distributors?
All SMAJ188H 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 SMAJ188H meets industry standards.
7.What is the process for return or replacement of SMAJ188H?
All SMAJ188H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ188H, 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 SMAJ188H part is unused and in its original packaging.
Return procedure for SMAJ188H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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