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Taiwan Semiconductor Corporation SMAJ30
- Part No.:
- SMAJ30
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ30.pdf
- Description:
- 400W, 37V, 10%, UNIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:8,450
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Product details
Overview
SMAJ30 from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power lines and signal paths. It features a 30 V working stand-off voltage (VWM), 33.3–40.7 V breakdown voltage (VBR) at 1 mA, 53.5 V maximum clamping voltage (VC) at 7.5 A peak pulse current, and 400 W peak pulse power rating per 10/1000 µs waveform - deployed in switching mode power supplies and on-board DC/DC converters.
For engineers reviewing the SMAJ30 datasheet, SMAJ30 pinout, SMAJ30 application, or SMAJ30 equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b transients, DO-214AC (SMA) package compatibility with automated placement, junction temperature range (–55 °C to +150 °C), and unidirectional polarity marking for correct PCB orientation.
Technical Context
The SMAJ30 operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology for stable breakdown behavior and low leakage (<1 µA at VWM). Its fast response time (<1.0 ps from 0 V to VBR min) ensures effective suppression of ESD and surge events before sensitive downstream circuitry is stressed.
It is rated for 400 W peak pulse power (10/1000 µs), derated linearly above 25 °C ambient per Fig.2, and supports up to 40 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine). The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements in its DO-214AC molded package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 30 V - Maximum continuous reverse operating voltage before significant leakage begins; sets upper limit for protected line voltage. |
| VBR min/max | 33.3 V / 40.7 V at IT = 1 mA - Confirmed avalanche onset range; ensures reliable triggering above normal operating voltage. |
| VC @ IPPM | 53.5 V at 7.5 A - Clamped voltage during 10/1000 µs surge; defines worst-case stress on downstream ICs. |
| PPPM | 400 W (10/1000 µs) - Peak transient energy handling capacity; sufficient for automotive load-dump and ISO 7637-2 compliance. |
| IR @ VWM | <1 µA - Ultra-low reverse leakage preserves efficiency in battery-powered or high-impedance circuits. |
| TJ max | +150 °C - Enables operation in under-hood automotive or enclosed industrial environments without thermal derating penalties. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with cathode band marking. Matte tin-plated leads meet J-STD-002 solderability; moisture sensitivity level (MSL) is Level 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side (e.g., GND or return path); conducts during forward surge or clamp event. |
| Cathode | Avalanche clamping terminal | Marked with band; connected to protected line (e.g., +30 V rail); initiates avalanche breakdown when VAK exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure. |
| Fast response time <1.0 ps | Enables suppression of sub-nanosecond ESD events before propagation into IC inputs or power rails. |
| ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance | Validated for automotive electronics protection against conducted transients including load dump and inductive switching spikes. |
| RoHS & halogen-free (IEC 61249-2-21) | Meets global environmental compliance mandates without compromising electrical performance or thermal robustness. |
Applications
| Switching Mode Power Supply (SMPS) | On-Board DC/DC Converter |
|---|---|
Use Scenario: Protection of primary-side MOSFET gate drivers and secondary-side rectifier outputs against flyback spikes and cross-talk surges. IC Role / Device Role: Unidirectional TVS placed across input/output rails to clamp transient overvoltage before reaching PWM controllers or synchronous rectifiers. Use Value: Limits peak stress to ≤53.5 V during 400 W surges, preserving MOSFET VDS margin and preventing controller latch-up. | Use Scenario: Input rail protection in point-of-load (POL) converters powering FPGAs or microprocessors in telecom base stations. IC Role / Device Role: Standoff-rated clamping element on 3.3 V, 5 V, or 12 V input bus to absorb coupling noise from adjacent high-speed digital switching. Use Value: Sub-1 µA leakage avoids loading low-current bias networks; DO-214AC footprint enables dense layout without thermal compromise. |
| Lighting Application | Adapter Protection |
Use Scenario: Overvoltage safeguard for LED driver ICs in outdoor streetlight systems exposed to lightning-induced surges on AC mains input. IC Role / Device Role: Secondary-side TVS on DC bus after bridge rectifier and bulk capacitor to suppress residual transients passing through EMI filter. Use Value: 150 °C max junction temperature supports operation inside sealed, thermally constrained luminaire enclosures. | Use Scenario: Input-stage protection in wall-mounted AC/DC adapters for consumer electronics subjected to plug-in surges and grid instability. IC Role / Device Role: First-line unidirectional suppressor on primary-side DC link (post-bridge, pre-PFC) to prevent PFC controller damage. Use Value: 40 A IFSM rating withstands repetitive inrush events; UL 94V-0 molding compound enhances fire safety in plastic housings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ30A | Narrower VBR range (33.3–36.8 V vs. 33.3–40.7 V); tighter tolerance improves predictability in precision clamp designs. | Better suited for systems requiring tighter clamping consistency across temperature and production lots. | Select SMAJ30A when VBR distribution control is critical; SMAJ30 offers broader availability and cost advantage for general-purpose use. |
| SMBJ30 | Same VWM/VBR/VC specs but in DO-214AA (SMB) package - 2.54 mm wider body, higher thermal mass, 600 W PPPM rating. | Preferred where board space allows larger footprint and higher surge margin is required beyond 400 W. | Choose SMBJ30 only if layout permits SMB package and system-level surge testing demands >400 W capability. |
Compared with SMAJ30A, the SMAJ30 provides wider VBR tolerance at lower cost, while SMBJ30 trades smaller footprint for higher power handling and thermal inertia - making SMAJ30 optimal for space-constrained 400 W surge protection where tight VBR control is not mandatory.
Availability
SMAJ30 is available at Aetrix Electronics and suitable for switching mode power supplies, on-board DC/DC converters, and lighting applications requiring stable component supply, consistent parametric performance, and full traceability across production batches.
Supply support for SMAJ30 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 surface-mount transient suppression in automotive, industrial, and consumer power systems - emphasizing high surge robustness, automated assembly compatibility, and AEC-Q101 readiness.
FAQ
What is the maximum clamping voltage of SMAJ30 under a 10/1000 µs surge?
The SMAJ30 has a maximum clamping voltage (VC) of 53.5 V when subjected to its rated peak pulse current of 7.5 A using the standardized 10/1000 µs waveform. This value is measured per JEDEC test conditions and represents the highest voltage that will appear across the SMAJ30 during such a transient event - critical for ensuring downstream components remain within their absolute maximum ratings.
Is SMAJ30 unidirectional or bidirectional, and how is polarity identified?
SMAJ30 is a unidirectional TVS diode, indicated by the absence of "C" or "CA" suffix. Polarity is marked on the DO-214AC package with a cathode band; the banded end connects to the protected line (anode to ground). Bidirectional variants (e.g., SMAJ30C) are separate part numbers with symmetrical breakdown in both directions.
Does SMAJ30 meet automotive transient immunity standards?
Yes, SMAJ30 meets ISO 7637-2 requirements for Pulses 1, 2a, 2b, 3a, and 3b - covering common conducted transients in 12 V automotive systems including load dump, alternator ripple, and inductive switch-off spikes. Its 400 W peak pulse power rating and 150 °C junction rating align with under-hood environmental demands.
What is the reverse leakage current specification for SMAJ30 at its working voltage?
At its 30 V working stand-off voltage (VWM), the SMAJ30 exhibits a maximum reverse leakage current (IR) of 1 µA at 25 °C. This ultra-low leakage minimizes standby power loss and avoids false triggering in high-impedance sensing or battery-backed circuits where even nanoamp-level currents impact performance.
Can SMAJ30 be used in place of SMAJ30A, and what is the key trade-off?
SMAJ30 can be substituted for SMAJ30A in most applications, but with a trade-off in VBR tolerance: SMAJ30 specifies 33.3–40.7 V, while SMAJ30A narrows this to 33.3–36.8 V. Use SMAJ30 where cost and availability prioritize broad clamping coverage; choose SMAJ30A only when tighter VBR control is required for precise overvoltage thresholding.
SMAJ30 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:
- 53.5V
- Current - Peak Pulse (10/1000µs):
- 7.5A
- 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)
SMAJ30 FAQ
1.How can I place an order for SMAJ30 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ30 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 SMAJ30 reliable?
The price and inventory of SMAJ30 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ30 is usually 5 days.
3.What payment methods are accepted for SMAJ30?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ30 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ30?
SMAJ30 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ30 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 SMAJ30?
For technical support, including SMAJ30 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ30 requirements.
6.How does Aetrix verify that SMAJ30 is sourced from the original manufacturer or authorized distributors?
All SMAJ30 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 SMAJ30 meets industry standards.
7.What is the process for return or replacement of SMAJ30?
All SMAJ30 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ30, 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 SMAJ30 part is unused and in its original packaging.
Return procedure for SMAJ30:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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