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Taiwan Semiconductor Corporation SMAJ54
- Part No.:
- SMAJ54
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ54.pdf
- Description:
- 400W, 66.7V, 10%, UNIDIRECTIONAL
- Quantity:
- Payment:
- Shipping:
Inventory:2,234
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Product details
Overview
SMAJ54 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 54 V working stand-off voltage (VWM), 60.0–73.3 V breakdown voltage (VBR) at 1 mA test current, 96.3 V maximum clamping voltage (VC) at 4.2 A peak impulse current, and 400 W peak pulse power rating per 10/1000 µs waveform.
For engineers reviewing the SMAJ54 datasheet, SMAJ54 pinout, SMAJ54 application, or SMAJ54 equivalent, key selection considerations include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b transients, junction temperature derating above 25°C, unidirectional polarity marking, and compatibility with automated SMT placement on 7,500-piece tape-and-reel delivery.
Technical Context
The SMAJ54 operates as a unidirectional avalanche diode, triggering when reverse voltage exceeds its specified VBR range to shunt surge energy away from sensitive downstream circuitry. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 µA at VWM), while the DO-214AC package supports high thermal dissipation up to 150°C junction temperature.
It delivers fast response (<1.0 ps from 0 V to VBR min) and meets automotive-grade transient immunity standards including ISO 7637-2. The device is rated for 400 W peak pulse power at TA = 25°C, derated linearly above ambient temperature per published curve, and supports single-pulse surge currents up to 4.2 A under 10/1000 µs conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 54 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC rail margin. |
| VBR @ IT=1 mA | 60.0–73.3 V - Breakdown voltage range at 1 mA test current; determines precise turn-on threshold tolerance. |
| VC @ IPPM=4.2 A | 96.3 V - Maximum clamped voltage during 10/1000 µs surge; sets worst-case stress on protected ICs. |
| PPPM (10/1000 µs) | 400 W - Peak pulse power handling capability; defines survivability against standardized automotive transients. |
| IR @ VWM | <1 µA - Reverse leakage at working voltage; ensures minimal standby power loss and signal integrity. |
| TJ max | 150 °C - Maximum junction temperature; enables operation in under-hood or high-power industrial environments. |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline with cathode band marking; compatible with J-STD-002 soldering. |
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, JEDEC-compliant mechanical dimensions.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to lower-potential side of protected line (e.g., GND or return path); conducts during forward surges. |
| Cathode | Reverse-biased clamping terminal | Connected to higher-potential side (e.g., +V rail); avalanches into conduction when reverse voltage exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable, repeatable breakdown voltage and long-term reliability under repeated surge stress. |
| Fast response time <1.0 ps | Enables effective suppression of nanosecond-scale ESD and fast-rising transients before downstream IC damage occurs. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validates suitability for automotive 12 V and 24 V system protection without additional external filtering. |
| Moisture sensitivity level 1 (J-STD-020) | Eliminates need for dry-pack or baking prior to reflow, simplifying manufacturing and reducing process risk. |
| Halogen-free & RoHS compliant | Meets environmental regulations for consumer, industrial, and automotive electronics supply chains. |
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 switching-induced voltage spikes and load dump transients. IC Role / Device Role / Timing Role: Unidirectional TVS placed across input/output rails to clamp overshoots exceeding 54 V while maintaining low leakage during normal operation. Use Value: Prevents cumulative degradation of MOSFETs and synchronous rectifiers by limiting peak reverse stress to ≤96.3 V under 400 W surges. | Use Scenario: Input rail protection in point-of-load (POL) converters powering FPGAs, microcontrollers, or sensors in industrial PLCs. IC Role / Device Role / Timing Role: Standoff-rated clamping device absorbing coupled noise and back-EMF from adjacent switching stages. Use Value: Maintains <1 µA leakage at 54 V, avoiding quiescent current errors in precision analog or low-power sleep modes. |
| Automotive Lighting Module | AC/DC Adapter Input Stage |
Use Scenario: Surge protection for LED driver ICs subjected to ISO 7637-2 Pulse 2b (battery disconnect) and Pulse 5a/b (load dump) events. IC Role / Device Role / Timing Role: Primary transient shunt on 12 V supply rail upstream of buck controller and gate driver. Use Value: Clamps 10/1000 µs load dump pulses to ≤96.3 V within <1 ps, preventing latch-up or gate oxide rupture in driver ICs. | Use Scenario: Input-stage protection in universal-input offline adapters exposed to AC line surges and hot-plug transients. IC Role / Device Role / Timing Role: First-line defense against differential-mode surges between L/N and common-mode surges referenced to earth. Use Value: Withstands 400 W peak pulse power and operates reliably from –55 °C to +150 °C, supporting wide ambient deployment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ54A | Narrower VBR range (60.0–66.3 V vs. 60.0–73.3 V); tighter tolerance improves clamping consistency but reduces margin for VBR drift. | Preferred where tighter VBR control is required for predictable clamping onset, especially in safety-critical or high-reliability systems. | Select SMAJ54A if design requires reduced VBR variation; otherwise SMAJ54 offers broader process margin. |
| SMBJ54 | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; higher thermal mass allows better power derating above 25°C. | Better suited for high-temperature environments (>85°C ambient) or applications requiring >400 W pulse handling with margin. | Choose SMBJ54 when board layout permits larger footprint and thermal performance is prioritized over space-constrained SMT placement. |
Compared with SMAJ54A and SMBJ54, the SMAJ54 balances cost-effective DO-214AC packaging, broad VBR tolerance for manufacturing yield, and full ISO 7637-2 compliance-making it optimal for volume automotive and industrial power supply designs where footprint and standardization are critical.
Availability
SMAJ54 is available at Aetrix Electronics and suitable for switching mode power supplies, automotive lighting modules, and on-board DC/DC converters requiring stable component supply, consistent parametric performance, and full traceability through J-STD-020 moisture-sensitive handling.
Supply support for SMAJ54 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 semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for industrial, automotive, and computing markets.
The SMAJ series is part of TSC's transient voltage suppressor product line, engineered specifically for high-reliability, surface-mount overvoltage protection in harsh electromagnetic environments such as automotive electronics and industrial power systems.
FAQ
What is the maximum clamping voltage of SMAJ54 under a 10/1000 µs surge?
The SMAJ54 has a maximum clamping voltage (VC) of 96.3 V when subjected to its rated peak impulse current of 4.2 A under the standardized 10/1000 µs waveform. This value is measured per JEDEC test conditions and defines the upper limit of voltage stress imposed on protected circuitry during transient events. The SMAJ54 maintains this clamping performance across its specified operating temperature range and is validated per ISO 7637-2 Pulse 1/2a/2b/3a/3b requirements.
Is SMAJ54 unidirectional or bidirectional, and how is polarity marked?
SMAJ54 is a unidirectional TVS diode, intended for protection of DC circuits with defined polarity. Polarity is marked by a cathode band on the DO-214AC (SMA) package body, aligned with the cathode terminal. This band must be oriented toward the higher-potential side of the protected line (e.g., +V rail), while the anode connects to the lower-potential side (e.g., ground). Bidirectional variants use the "CA" suffix (e.g., SMAJ54CA), which SMAJ54 does not carry.
What is the reverse leakage current specification for SMAJ54 at its working stand-off voltage?
The SMAJ54 exhibits a maximum reverse leakage current (IR) of 1 µA when biased at its 54 V working stand-off voltage (VWM), measured at 25°C ambient temperature. This low leakage ensures minimal power loss and avoids interference with high-impedance sensing or bias networks. The SMAJ54 maintains this IR specification across its full operating junction temperature range (–55 °C to +150 °C), supporting reliable performance in thermally demanding applications.
Does SMAJ54 meet automotive transient immunity standards?
Yes, the SMAJ54 is explicitly rated to meet ISO 7637-2 for automotive transient immunity, covering Pulse 1 (inductive load disconnect), Pulse 2a (sudden load removal), Pulse 2b (battery feed disconnection), Pulse 3a (capacitive coupled noise), and Pulse 3b (inductively coupled noise). These qualifications are documented in Taiwan Semiconductor's official datasheet revision U2102 and verified under standard test waveforms and mounting conditions. The SMAJ54 is widely deployed in automotive lighting, body control, and infotainment power rails.
What is the moisture sensitivity level (MSL) and reflow profile compatibility for SMAJ54?
The SMAJ54 is rated MSL Level 1 per J-STD-020, meaning it has unlimited floor life and does not require dry-packaging or baking prior to reflow soldering. It is compatible with standard lead-free reflow profiles, including peak temperatures up to 260°C, and its matte tin-plated leads comply with J-STD-002 for solderability. The DO-214AC (SMA) package uses UL 94V-0 flame-retardant molding compound, supporting automated placement and high-yield assembly without special handling.
SMAJ54 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):
- 54V
- Voltage - Breakdown (Min):
- 60V
- Voltage - Clamping (Max) @ Ipp:
- 96.3V
- Current - Peak Pulse (10/1000µs):
- 4.2A
- 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)
SMAJ54 FAQ
1.How can I place an order for SMAJ54 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ54 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 SMAJ54 reliable?
The price and inventory of SMAJ54 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ54 is usually 5 days.
3.What payment methods are accepted for SMAJ54?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ54 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ54?
SMAJ54 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ54 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 SMAJ54?
For technical support, including SMAJ54 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ54 requirements.
6.How does Aetrix verify that SMAJ54 is sourced from the original manufacturer or authorized distributors?
All SMAJ54 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 SMAJ54 meets industry standards.
7.What is the process for return or replacement of SMAJ54?
All SMAJ54 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ54, 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 SMAJ54 part is unused and in its original packaging.
Return procedure for SMAJ54:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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