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Taiwan Semiconductor Corporation SMAJ18CAH
- Part No.:
- SMAJ18CAH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18CAH.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,500
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Product details
Overview
SMAJ18CAH from Taiwan Semiconductor is a bidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive-grade overvoltage protection with 18V working stand-off voltage, 20.0–22.1V breakdown range at 1mA test current, and 32.2V maximum clamping voltage at 13.7A peak impulse current. It protects DC/DC converters and lighting circuits against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ18CAH datasheet, SMAJ18CAH pinout, SMAJ18CAH application, or SMAJ18CAH equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, 150°C junction temperature rating, moisture sensitivity level 1 compliance, and DO-214AC mechanical compatibility with automated SMT placement.
Technical Context
SMAJ18CAH is a glass-passivated, single-die, bidirectional TVS diode optimized for fast transient suppression in automotive and industrial power rails. Its junction exhibits sub-1.0ps response time from 0V to VBR min and maintains <1μA reverse leakage above 10V.
The device delivers 400W peak pulse power under 10/1000μs waveform up to 78V VWM; above 78V, derated to 300W. It meets ISO 7637-2 immunity requirements for vehicle electrical systems and operates across –55°C to +150°C junction temperature range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before clamping begins |
| VBR @ IT=1mA | 20.0–22.1 V - Verified breakdown threshold ensuring reliable turn-on during transients |
| VC @ IPPM=13.7A | 32.2 V - Clamped voltage limiting downstream IC stress during 10/1000μs surge |
| PPPM | 400 W - Peak pulse power handling per 10/1000μs waveform at TA=25°C |
| IR @ VWM | <1 μA - Minimal leakage preserving efficiency in low-power standby modes |
| TJ max | +150 °C - Enables operation in under-hood automotive 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, polarity indicated by cathode band; weight ≈0.060g; UL 94V-0 rated compound; JESD 201 Class 2 whisker resistant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Transient return path for bidirectional clamping | Completes symmetrical conduction path during both positive and negative voltage excursions |
| Cathode (banded end) | Transient return path for bidirectional clamping | Enables identical clamping behavior in either polarity-no directional installation required |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including temperature cycling, HTRB, and ESD |
| Fast response time | <1.0 ps from 0 V to VBR min ensures clamping activation before sensitive circuitry sustains damage |
| ISO 7637-2 compliance | Withstands Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) waveforms |
| Glass passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal/humidity stress |
| Moisture sensitivity level 1 | Zero floor life limitation-no baking required prior to reflow, simplifying manufacturing flow |
Applications
| Automotive Lighting Systems | On-Board DC/DC Converters |
|---|---|
Use Scenario: Protecting LED driver ICs and MOSFETs from load dump and alternator ripple in headlamp and tail lamp modules. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed across input rail to shunt transients before they reach switching regulators. Use Value: Prevents latch-up or gate oxide failure in 40V-rated buck controllers by limiting rail voltage to ≤32.2V during 10/1000μs surges. |
Use Scenario: Safeguarding isolated flyback or buck-boost converters powering infotainment and ADAS ECUs. IC Role / Device Role / Timing Role: Primary-side rail protector absorbing ISO 7637-2 Pulse 1 energy upstream of input filter capacitors. Use Value: Maintains system uptime by preventing shutdown or reset events caused by >100V transients on 12V/24V vehicle buses. |
| Industrial Switching Power Supplies | AC-DC Adapters |
Use Scenario: Input-stage surge protection in DIN-rail mounted SMPS units exposed to lightning-induced line transients. IC Role / Device Role / Timing Role: First-line defense parallel to bulk capacitor, clamping line-to-ground spikes within nanoseconds. Use Value: Reduces need for oversized X/Y capacitors and extends lifetime of bridge rectifiers by limiting peak reverse voltage. |
Use Scenario: Secondary-side overvoltage suppression in universal-input adapters for consumer and medical devices. IC Role / Device Role / Timing Role: Output rail clamp preventing damage to USB-PD controllers and load switches during hot-plug events. Use Value: Ensures compliance with IEC/EN 62368-1 transient immunity requirements without adding active regulation overhead. |
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 SMAJ18CA | Same DO-214AC package and 18V VWM, but rated for 300W peak power (vs. 400W) above 78V; no AEC-Q101 documentation publicly available | Acceptable for non-automotive industrial use where ISO 7637-2 compliance is not mandated | Select when cost sensitivity outweighs automotive qualification and full 400W rating at elevated VWM |
| Vishay SMAJ18CAHE3/5BT | Identical 400W rating and AEC-Q101 qualification; same VBR/VC specs; differs only in tape-and-reel packaging (5,000 pcs vs. 7,500 pcs) | No functional difference-drop-in replacement for production continuity or dual-sourcing | Prefer for high-volume automotive programs requiring traceable lot control and extended supply chain resilience |
Compared with Littelfuse SMAJ18CA and Vishay SMAJ18CAHE3/5BT, SMAJ18CAH provides verified 400W pulse handling across its full voltage range and documented AEC-Q101 qualification-critical for Tier 1 automotive BOMs where failure mode analysis requires certified stress test evidence.
Availability
SMAJ18CAH is available at Aetrix Electronics and suitable for automotive lighting systems, on-board DC/DC converters, and industrial switching power supplies requiring stable component supply with AEC-Q101 assurance and ISO 7637-2 compliance.
Supply support for SMAJ18CAH 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.
SMAJ18CAH belongs to TSC's AEC-Q101-qualified SMAJ-H series-designed specifically for robust transient suppression in harsh automotive environments where reliability under thermal cycling and electrical overstress is non-negotiable.
FAQ
What does the "CAH" suffix indicate in SMAJ18CAH?
The "CAH" suffix in SMAJ18CAH denotes a bidirectional configuration (C), an improved AEC-Q101-qualified version (A), and the standard high-power DO-214AC (SMA) package (H). Unlike unidirectional variants (e.g., SMAJ18AH), SMAJ18CAH provides symmetrical clamping for both positive and negative transients without polarity-sensitive mounting.
Is SMAJ18CAH suitable for ISO 7637-2 Pulse 1 protection?
Yes, SMAJ18CAH is explicitly rated to meet ISO 7637-2 Pulse 1 (inductive load dump), Pulse 2a/2b, and Pulse 3a/3b requirements. Its 400W peak pulse power rating and 32.2V clamping voltage at 13.7A ensure effective suppression of the 10/1000μs waveform defined in the standard, making it appropriate for 12V and 24V automotive power networks.
How does SMAJ18CAH differ from SMAJ18AH?
SMAJ18AH is unidirectional with cathode-anode polarity; SMAJ18CAH is bidirectional with symmetrical VBR and VC in both directions. SMAJ18CAH has identical VWM (18V), VBR (20.0–22.1V), and VC (32.2V) specs but eliminates orientation constraints-critical for space-constrained layouts where polarity marking may be ambiguous or omitted.
What is the maximum operating temperature for SMAJ18CAH?
SMAJ18CAH has a maximum junction temperature (TJ) of +150°C and operates across –55°C to +150°C. This rating supports deployment in under-hood automotive locations and industrial enclosures where ambient temperatures exceed 105°C, provided PCB copper area and airflow maintain junction temperature within limit.
Does SMAJ18CAH require special handling due to moisture sensitivity?
No-SMAJ18CAH is rated at Moisture Sensitivity Level 1 per J-STD-020, meaning it has unlimited floor life and can be processed directly through standard reflow without pre-baking. This simplifies SMT assembly and reduces manufacturing risk compared to higher-MSL components requiring dry-pack storage and bake-out protocols.
SMAJ18CAH 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):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 13.7A
- 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)
SMAJ18CAH FAQ
1.How can I place an order for SMAJ18CAH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18CAH 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 SMAJ18CAH reliable?
The price and inventory of SMAJ18CAH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18CAH is usually 5 days.
3.What payment methods are accepted for SMAJ18CAH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18CAH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18CAH?
SMAJ18CAH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18CAH 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 SMAJ18CAH?
For technical support, including SMAJ18CAH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18CAH requirements.
6.How does Aetrix verify that SMAJ18CAH is sourced from the original manufacturer or authorized distributors?
All SMAJ18CAH 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 SMAJ18CAH meets industry standards.
7.What is the process for return or replacement of SMAJ18CAH?
All SMAJ18CAH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18CAH, 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 SMAJ18CAH part is unused and in its original packaging.
Return procedure for SMAJ18CAH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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