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Taiwan Semiconductor Corporation SMAJ30A
- Part No.:
- SMAJ30A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ30A.pdf
- Description:
- TVS DIODE 30VWM 48.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:15,000
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Product details
Overview
SMAJ30A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in DC power rails. It features a 30 V working stand-off voltage (VWM), 33.3–36.8 V breakdown voltage (VBR), 48.4 V maximum clamping voltage (VC) at 8.3 A peak pulse current, and 400 W peak pulse power rating per 10/1000 µs waveform - ideal for protecting SMPS outputs and DC/DC converter inputs against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ30A datasheet, SMAJ30A pinout, SMAJ30A application, or SMAJ30A equivalent, key selection criteria include clamping performance under 10/1000 µs surge, low leakage (<1 µA at 30 V), fast response (<1.0 ps), RoHS/halogen-free compliance, and DO-214AC mechanical compatibility with automated SMT assembly lines.
Technical Context
The SMAJ30A operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve stable reverse breakdown and low capacitance. Its clamping behavior is defined by a 10/1000 µs double-exponential pulse waveform, with peak impulse current (IPPM) rated at 8.3 A and clamping voltage (VC) tightly controlled at ≤48.4 V - ensuring predictable voltage limiting during automotive load-dump or inductive switching events.
It supports operation across –55 °C to +150 °C junction temperature range and meets JESD201 Class 2 whisker resistance and J-STD-020 Moisture Sensitivity Level 1 requirements. The device is not bidirectional; polarity is marked via cathode band, and forward voltage is specified at 3.5 V @ 25 A for surge validation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 30 V - maximum continuous reverse operating voltage before conduction begins; sets system rail margin for reliable standby operation |
| VBR min/max | 33.3 V / 36.8 V @ 1 mA - verified avalanche onset range ensures consistent turn-on across production lots |
| VC @ IPPM | 48.4 V @ 8.3 A - clamping voltage under standardized 10/1000 µs surge defines protected circuit's worst-case overvoltage exposure |
| PPPM | 400 W - peak pulse power handling capability determines survivability against short-duration energy transients |
| IR @ VWM | <1 µA - ultra-low reverse leakage preserves efficiency in high-impedance bias networks and battery-backed circuits |
| Package | DO-214AC (SMA) - industry-standard surface-mount outline enabling automated placement and reflow compatibility |
| TJ max | +150 °C - enables use in under-hood automotive modules and thermally constrained industrial enclosures |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band; weight ≈ 0.060 g; UL 94V-0 rated compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / Cathode-referenced reference node | Connected to ground or low-side return path; defines directionality for unidirectional clamping |
| Cathode | Reverse-biased terminal / Clamping output node | Connected to protected line (e.g., 30 V rail); conducts avalanche current to anode during overvoltage |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Ensures long-term stability of VBR and IR across thermal cycling and humidity exposure per J-STD-020 MSL-1 |
| Clamping voltage ≤48.4 V | Guarantees downstream ICs rated for 45–50 V absolute maximum survive ISO 7637-2 Pulse 2b (inductive switch-off) |
| Response time <1.0 ps | Enables suppression of nanosecond-scale ESD and fast-rising transients before sensitive logic is damaged |
| RoHS & halogen-free | Complies with IEC 61249-2-21 and EU RoHS Directive 2011/65/EU for green manufacturing and end-of-life processing |
| 400 W peak pulse power | Supports single-event surge immunity up to 8.3 A (10/1000 µs), exceeding typical automotive load-dump requirements |
Applications
| Switching Mode Power Supply (SMPS) Output Protection | Automotive On-Board DC/DC Converter |
|---|---|
Use Scenario: Protecting regulated 30 V output rail of isolated flyback or forward converter against line transients and feedback loop faults. IC Role / Device Role / Timing Role: Unidirectional TVS placed between output and ground, clamping surges before they reach post-regulation filters or load ICs. Use Value: Limits output overvoltage to ≤48.4 V during 10/1000 µs surges, preventing latch-up or gate oxide damage in downstream 50 V-rated MOSFETs or controllers. | Use Scenario: Safeguarding 30 V intermediate bus in automotive body control module (BCM) DC/DC stage exposed to ISO 7637-2 Pulse 1 (battery disconnect) and Pulse 3b (capacitive coupling). IC Role / Device Role / Timing Role: Standby protection element connected directly across input capacitor, activated only during transient events. Use Value: Withstands ≥8.3 A peak current while holding clamped voltage below 48.4 V, preserving integrity of 40 V-rated buck controller and gate drivers. |
| Industrial LED Driver Input Stage | Telecom Adapter Surge Interface |
Use Scenario: Shielding constant-current LED driver IC input from 30 V supply rail surges caused by nearby relay switching or motor commutation. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main DC input, positioned upstream of EMI filter and bulk capacitor. Use Value: Ultra-low IR (<1 µA) avoids loading the 30 V rail during normal operation; fast <1 ps response prevents LED string current disruption during microsecond transients. | Use Scenario: Front-end protection for universal-input AC/DC adapter delivering 30 V output, subjected to EN 61000-4-5 line surge testing. IC Role / Device Role / Timing Role: Secondary-side TVS on DC output, complementing primary-side MOVs to meet full-system surge immunity. Use Value: 400 W rating and DO-214AC footprint allow direct integration into compact adapter PCBs without derating or heatsinking. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ30 | Higher clamping voltage (53.5 V @ 7.5 A) and wider VBR range (33.3–40.7 V); same DO-214AC package and VWM | Less effective clamping margin for 45 V-rated loads; suitable where higher surge current tolerance is prioritized over tight voltage limiting | Select SMAJ30 when peak current >8.3 A is expected and clamping voltage margin allows ≥53.5 V excursion |
| SMBJ30A | Same electrical specs but in larger DO-214AA (SMB) package; 600 W peak power rating; identical VWM/VBR/VC values | Requires PCB layout change due to larger footprint; preferred for higher reliability in high-temperature or high-humidity environments | Choose SMBJ30A when thermal derating headroom or long-term field reliability under cyclic stress is critical |
Compared with SMAJ30 and SMBJ30A, the SMAJ30A delivers optimal balance of tight clamping (48.4 V), low leakage (<1 µA), and compact DO-214AC packaging - making it the preferred choice for space-constrained 30 V rail protection where precise voltage limiting is required.
Availability
SMAJ30A is available at Aetrix Electronics and suitable for switching mode power supplies, automotive DC/DC converters, and industrial LED drivers requiring stable component supply with full traceability and lifecycle management.
Supply support for SMAJ30A 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 was developed specifically for high-reliability, surface-mount transient suppression in automotive, industrial, and telecom power systems - emphasizing low clamping voltage, fast response, and robust JEDEC-compliant packaging.
FAQ
What is the maximum clamping voltage of the SMAJ30A under standard test conditions?
The SMAJ30A has a maximum clamping voltage (VC) of 48.4 V when subjected to an 8.3 A peak impulse current with a 10/1000 µs waveform at TA = 25 °C. This value is measured per JEDEC standards and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ30A maintains this clamping performance consistently across its qualified operating temperature range, and the value is guaranteed in the official Taiwan Semiconductor datasheet revision U2102.
Is the SMAJ30A suitable for bidirectional transient protection?
No, the SMAJ30A is a unidirectional TVS diode and is not rated for bidirectional operation. Its electrical characteristics - including breakdown voltage, clamping, and leakage - apply only in the reverse direction, with polarity marked by a cathode band. For bidirectional protection at 30 V standoff, Taiwan Semiconductor specifies the SMAJ30CA variant. Using SMAJ30A in bidirectional configurations may result in forward conduction failure or inadequate positive-going transient suppression.
What is the junction temperature rating for the SMAJ30A?
The SMAJ30A has a specified operating junction temperature range of –55 °C to +150 °C, with a maximum steady-state power dissipation (PD) of 1 W. Its thermal performance is validated per JEDEC JESD51-1, and the device remains fully functional within this range when mounted on standard FR-4 PCBs with recommended pad layout. Derating curves in the datasheet confirm that the 400 W peak pulse rating applies only at TA = 25 °C and must be reduced linearly above that ambient temperature - a key consideration in enclosed or high-temperature applications.
Does the SMAJ30A meet automotive transient immunity standards?
Yes, the SMAJ30A is explicitly rated to meet ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test waveforms - covering common automotive electrical disturbances such as load dump, alternator ripple, and capacitive coupling transients. Its 400 W peak pulse power rating, fast <1.0 ps response time, and low clamping voltage make it suitable for front-end protection in 12 V and 24 V vehicle subsystems. Compliance is verified per manufacturer test reports and referenced in the U2102 datasheet.
What packaging and reel quantity is offered for the SMAJ30A?
The SMAJ30A is supplied in DO-214AC (SMA) package format on 7,500-unit tape-and-reel carriers, conforming to EIA-481-D standards. The reels include full traceability data, moisture sensitivity level (MSL) 1 labeling per J-STD-020, and RoHS/halogen-free certification documentation. Aetrix Electronics provides both full reels and cut-tape options with verified lot traceability and no repackaging - supporting both high-volume production and NPI prototyping requirements for the SMAJ30A.
SMAJ30A 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):
- 30V
- Voltage - Breakdown (Min):
- 33.3V
- Voltage - Clamping (Max) @ Ipp:
- 48.4V
- Current - Peak Pulse (10/1000µs):
- 8.3A
- 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)
SMAJ30A FAQ
1.How can I place an order for SMAJ30A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ30A 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 SMAJ30A reliable?
The price and inventory of SMAJ30A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ30A is usually 5 days.
3.What payment methods are accepted for SMAJ30A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ30A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ30A?
SMAJ30A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ30A 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 SMAJ30A?
For technical support, including SMAJ30A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ30A requirements.
6.How does Aetrix verify that SMAJ30A is sourced from the original manufacturer or authorized distributors?
All SMAJ30A 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 SMAJ30A meets industry standards.
7.What is the process for return or replacement of SMAJ30A?
All SMAJ30A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ30A, 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 SMAJ30A part is unused and in its original packaging.
Return procedure for SMAJ30A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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