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Taiwan Semiconductor Corporation SMBJ18AH
- Part No.:
- SMBJ18AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AA, SMB
- Datasheet:
-
SMBJ18AH.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AA
- Quantity:
- Payment:
- Shipping:
Inventory:5,363
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Product details
Overview
SMBJ18AH from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AA (SMB) package, rated for 600W peak pulse power, 18V working stand-off voltage (VWM), and 29.2V maximum clamping voltage (VC) at 21.5A peak impulse current - designed to protect automotive and industrial power rails against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMBJ18AH datasheet, SMBJ18AH pinout, SMBJ18AH application, or SMBJ18AH equivalent, this page delivers verified electrical parameters, AEC-Q101 qualification status, clamping performance under 10/1000µs surge, thermal resistance (RθJA = 55°C/W), and bidirectional variant compatibility (SMBJ18CAH).
Technical Context
The SMBJ18AH operates as a unidirectional avalanche diode with glass-passivated junction, delivering sub-1ps response time and <1µA blocking leakage above 10V. Its breakdown voltage range is 20.0–22.1V at 1mA test current, ensuring precise overvoltage thresholding for 12V/24V system rails.
Thermally, it features RθJC = 10°C/W and RθJA = 55°C/W, enabling reliable operation up to +150°C junction temperature. It meets JESD201 Class 2 whisker resistance and J-STD-020 Moisture Sensitivity Level 1 - supporting lead-free reflow without popcorn risk.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins; sets safe margin below 24V nominal rail. |
| VBR min/max | 20.0 / 22.1 V @ 1 mA - Confirmed avalanche onset range; ensures consistent turn-on across production lots. |
| VC @ IPP | 29.2 V @ 21.5 A - Clamped voltage during 10/1000µs surge; limits downstream IC stress to ≤30V. |
| PPK | 600 W - Peak pulse power handling per single 10/1000µs transient; supports ISO 7637-2 compliance. |
| ID @ VWM | <1 µA - Ultra-low leakage at rated stand-off; avoids parasitic loading on low-power sensor circuits. |
| TJ max | +150 °C - Maximum junction temperature; enables use in under-hood automotive environments. |
| RθJA | 55 °C/W - Thermal resistance to ambient; defines PCB copper area requirements for sustained power dissipation. |
Pinout & Package
DO-214AA (SMB) surface-mount package with cathode band marking; matte tin-plated leads compliant with J-STD-002 solderability; weight ≈0.090g; UL 94V-0 molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction path (uni-directional) | Connected to protected circuit ground; conducts surge current to GND when cathode exceeds VWM. |
| Cathode | Transient clamp input node | Connected to supply rail (e.g., 24V line); initiates avalanche breakdown when voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive-grade reliability including temperature cycling, HTRB, and ESD testing per stress test plan. |
| Glass passivated junction | Ensures stable VBR over lifetime and immunity to humidity-induced parameter drift in harsh environments. |
| Fast response time <1 ps | Clamps transients before sensitive logic or analog circuitry experiences damaging overvoltage. |
| Meets ISO 7637-2 Pulse 1/2a/2b/3a/3b | Guarantees protection against load dump, inductive switching, and EFT events in 12V/24V vehicle networks. |
| Halogen-free & RoHS compliant | Complies with IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for environmentally restricted markets. |
Applications
| Automotive Power Rail Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 24V battery-fed ECUs from load dump and alternator transients in passenger vehicles and commercial trucks. IC Role / Device Role / Timing Role: Unidirectional TVS placed between battery rail and DC-DC input stage to clamp surges before regulator damage. Use Value: Limits clamped voltage to 29.2V, preserving 36V-rated input capacitors and avoiding regulator shutdown during ISO 7637-2 Pulse 5a events. | Use Scenario: Shielding 4–20mA current loop transmitters from ESD and cable-induced fast transients in factory automation systems. IC Role / Device Role / Timing Role: TVS mounted at connector entry point to shunt EFT energy before reaching precision op-amps and ADC front-ends. Use Value: Sub-1ps response prevents >100ns overvoltage spikes from corrupting analog measurements or triggering false fault detection. |
| LED Lighting Driver Protection | Motor Control Board Surge Suppression |
Use Scenario: Safeguarding constant-current LED drivers in outdoor street lighting from lightning-induced surges on AC mains input. IC Role / Device Role / Timing Role: Primary-side TVS on rectified DC bus to absorb repetitive 600W transients without degradation. Use Value: 600W PPK rating sustains repeated 10/1000µs pulses while maintaining VBR stability over 1000+ cycles. | Use Scenario: Protecting gate drivers and MCU I/O pins from inductive kickback during BLDC motor commutation in HVAC and pump controllers. IC Role / Device Role / Timing Role: Localized TVS at motor driver output stage to clamp flyback voltage spikes before reaching half-bridge FETs. Use Value: 29.2V clamping prevents gate oxide breakdown in 30V-rated MOSFETs during 100A+ switching transitions. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ18A | VWM = 18V, VC = 29.2V @ 21.5A, same DO-214AC (SMA) footprint but lower PPK (400W) | Lower surge capacity limits use to non-automotive, lower-energy transients | Select when cost sensitivity outweighs ISO 7637-2 compliance needs and PCB space allows SMA package. |
| Vishay SMF18A | VWM = 18V, VC = 28.8V @ 21.9A, DO-214AB (SMB) package, 200W PPK only | Insufficient for automotive load dump; suitable only for consumer-level ESD protection | Choose only for board-level ESD hardening where 600W surge immunity is not required. |
Compared with SMAJ18A and SMF18A, SMBJ18AH delivers full 600W surge capability in the same DO-214AA footprint, maintains AEC-Q101 qualification, and provides verified ISO 7637-2 Pulse 5a resilience - making it the only option among the three qualified for under-hood automotive deployment.
Availability
SMBJ18AH is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, and LED driver surge suppression requiring stable component supply across high-volume production programs.
Supply support for SMBJ18AH 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, and rectifiers since 1979.
The SMBJH series was engineered specifically for AEC-Q101-compliant automotive transient suppression, emphasizing robust clamping consistency, low leakage, and high-reliability packaging for under-hood and chassis-mounted electronics.
FAQ
What is the maximum clamping voltage of SMBJ18AH under a 10/1000µs surge?
The SMBJ18AH has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak impulse current of 21.5 A using the standard 10/1000µs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees predictable overvoltage limiting for downstream 30V-rated components in 24V systems.
Is SMBJ18AH suitable for bidirectional transient protection?
No - SMBJ18AH is a unidirectional TVS diode. For bidirectional protection, use SMBJ18CAH (with CAH suffix), which provides symmetrical clamping in both polarities and shares identical VWM, VC, and PPK ratings. The "A" in SMBJ18AH denotes tighter VBR tolerance (±5%), not polarity.
Does SMBJ18AH meet automotive qualification standards?
Yes, SMBJ18AH is AEC-Q101 qualified and tested per the full stress test schedule, including HTGB, H3TRB, TC, and ESD. It also meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements - confirming suitability for automotive power net applications such as body control modules and ADAS domain controllers.
What is the thermal resistance from junction to ambient for SMBJ18AH?
The SMBJ18AH has a junction-to-ambient thermal resistance (RθJA) of 55°C/W under standard JEDEC test conditions (single-layer 1 in² copper pad). This value guides PCB layout design - doubling copper area typically reduces RθJA by ~15%, critical for sustaining repetitive surge duty cycles.
How does the "A" suffix in SMBJ18AH affect its electrical parameters?
The "A" suffix indicates a tighter breakdown voltage tolerance: SMBJ18AH has VBR = 20.0–22.1 V (±5% around 21.05 V nominal), whereas SMBJ18H is 20.0–24.4 V (±10%). All other parameters - including VWM, VC, IPP, and PPK - remain identical between the two variants.
SMBJ18AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AA, SMB
- Series:
- SMBJH
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 21.5A
- Power - Peak Pulse:
- 600W
- 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-214AA (SMB)
SMBJ18AH FAQ
1.How can I place an order for SMBJ18AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMBJ18AH 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 SMBJ18AH reliable?
The price and inventory of SMBJ18AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMBJ18AH is usually 5 days.
3.What payment methods are accepted for SMBJ18AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMBJ18AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMBJ18AH?
SMBJ18AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMBJ18AH 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 SMBJ18AH?
For technical support, including SMBJ18AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMBJ18AH requirements.
6.How does Aetrix verify that SMBJ18AH is sourced from the original manufacturer or authorized distributors?
All SMBJ18AH 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 SMBJ18AH meets industry standards.
7.What is the process for return or replacement of SMBJ18AH?
All SMBJ18AH units undergo pre-shipment inspection (PSI). If there is an issue with SMBJ18AH, 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 SMBJ18AH part is unused and in its original packaging.
Return procedure for SMBJ18AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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