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Taiwan Semiconductor Corporation SMAJ45H
- Part No.:
- SMAJ45H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ45H.pdf
- Description:
- TVS DIODE 45VWM 80.3VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,450
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Product details
Overview
SMAJ45H from Taiwan Semiconductor is a unidirectional 400W surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, with 45V working stand-off voltage (VWM), 50.0–61.1V breakdown voltage (VBR), and 80.3V maximum clamping voltage (VC) at 5.0A peak pulse current. It delivers fast response (<1.0ps), low leakage (<1μA @ 45V), and AEC-Q101 qualification for automotive-grade surge protection in DC/DC converters and SMPS rails.
For engineers reviewing the SMAJ45H datasheet, SMAJ45H pinout, SMAJ45H application, or SMAJ45H equivalent, this page provides verified electrical parameters, clamping performance under 10/1000μs transients, ISO 7637-2 compliance details, DO-214AC mechanical data, and validated alternative parts for automotive power rail protection design.
Technical Context
The SMAJ45H operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve stable reverse-biased clamping during ESD and load-dump events. Its 150°C max junction temperature and J-STD-020 Level 1 moisture sensitivity support reflow-compatible automated assembly in harsh environments.
Designed for single-pulse transient suppression per IEC 61000-4-2 and ISO 7637-2 Pulse 1/2a/2b/3a/3b, it sustains 400W peak pulse power (10/1000μs) up to 25°C with linear derating above ambient - delivering predictable VC = 80.3V @ IPPM = 5.0A without degradation across its -55°C to +150°C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45 V - Maximum continuous reverse voltage before clamping begins; sets safe operating margin for 48V nominal systems |
| VBR @ IT=1mA | 50.0–61.1 V - Confirmed breakdown threshold ensures reliable turn-on during overvoltage events |
| VC @ IPPM=5.0A | 80.3 V - Clamped voltage limits downstream IC stress during 10/1000μs surges |
| PPPM | 400 W - Peak pulse power rating supports automotive load-dump immunity per ISO 7637-2 |
| IR @ VWM | <1 μA - Negligible standby leakage preserves battery life in always-on vehicle modules |
| Package | DO-214AC (SMA) - Standardized surface-mount footprint compatible with high-volume SMT lines |
Pinout & Package
DO-214AC (SMA) package: molded plastic 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 | Forward conduction terminal | Connected to system ground or lower-potential rail in unidirectional configuration |
| Cathode | Clamping output terminal | Connected to protected line (e.g., 48V supply rail); conducts surge current to ground when VIN exceeds VBR |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive electronics per stress test requirements including HTOL, TCT, and ESD HBM/MM |
| Glass passivated junction | Ensures stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure |
| Fast response time <1.0ps | Clamps transients before sensitive downstream circuitry experiences damaging overvoltage |
| ISO 7637-2 compliant | Meets Pulse 1 (inductive switch-off), Pulse 2a (battery disconnect), Pulse 3a/3b (line impedance switching) waveforms |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive for environmentally constrained applications |
Applications
| Automotive Body Control Module (BCM) | Industrial 48V DC/DC Converter |
|---|---|
Use Scenario: Protecting CAN transceiver power input against load-dump surges during alternator regulation faults. IC Role / Device Role / Timing Role: Unidirectional TVS placed between 48V rail and ground to clamp transients before they reach the DC/DC controller IC. Use Value: Limits voltage to ≤80.3V during 400W pulses, preventing latch-up or gate oxide damage in buck controller ICs rated for 100V absolute max. | Use Scenario: Safeguarding primary-side MOSFET gate drivers in isolated flyback converters subjected to lightning-induced coupling. IC Role / Device Role / Timing Role: Standoff protector on auxiliary bias rail, activated only during >50V transients while remaining inert during normal 45V operation. Use Value: Maintains <1μA leakage at 45V, eliminating quiescent current penalty while enabling sub-100ns clamping response to fast-rising spikes. |
| Telecom Remote Radio Unit (RRU) | Commercial LED Driver Power Stage |
Use Scenario: Shielding PoE-powered baseband processor inputs from induced surges on outdoor fiber-to-the-tower cabling. IC Role / Device Role / Timing Role: Secondary-side TVS on 48V DC input stage, coordinated with upstream MOVs to distribute energy absorption. Use Value: Delivers precise 80.3V clamping with no follow-on conduction, avoiding latch-up risks that plague bidirectional alternatives in asymmetric rail designs. | Use Scenario: Suppressing inductive kickback from high-current LED string switching in smart streetlight drivers. IC Role / Device Role / Timing Role: Parallel-connected TVS across bulk capacitor input to absorb repetitive 10/1000μs spikes generated by MOSFET commutation. Use Value: Withstands 400W peak pulses without parameter shift, ensuring consistent clamping performance over 10+ year field deployment in outdoor thermal cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ45AH | Narrower VBR range (50.0–55.3V vs. 50.0–61.1V); tighter 10% tolerance | Better suited for precision-clamp designs where VC must stay below 75V under worst-case VBR | Select SMAJ45AH when system-level margin requires guaranteed clamping ≤72.7V at 5.5A |
| SMBJ45A | Same VWM/VBR but higher PPPM = 600W (10/1000μs); SMB package (DO-214AA) | Used where higher surge energy handling is needed and PCB space allows larger footprint | Choose SMBJ45A only if 600W rating is required and layout accommodates 4.58mm × 3.94mm vs. SMAJ45H's 4.57mm × 2.79mm |
Compared with SMAJ45AH and SMBJ45A, the SMAJ45H offers broader VBR tolerance for cost-sensitive automotive modules, maintains identical DO-214AC footprint for drop-in replacement in legacy SMA layouts, and balances clamping performance with AEC-Q101 validation - making it optimal for volume production of 48V subsystems where 400W surge immunity suffices.
Availability
SMAJ45H is available at Aetrix Electronics and suitable for automotive body control modules, industrial 48V DC/DC converters, and commercial LED driver power stages requiring stable component supply across extended temperature ranges and high-reliability manufacturing.
Supply support for SMAJ45H 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, serving global automotive, industrial, and consumer markets since 1979.
The SMAJ series is part of TSC's AEC-Q101-qualified TVS portfolio, engineered specifically for robust transient suppression in 12V–48V automotive power networks and industrial DC distribution systems.
FAQ
What is the maximum clamping voltage of the SMAJ45H under standard test conditions?
The SMAJ45H exhibits a maximum clamping voltage (VC) of 80.3 V when subjected to a 10/1000μs waveform with a peak pulse current (IPPM) of 5.0 A at TA = 25°C. This value is measured per Fig.5 in the official datasheet and defines the upper voltage limit imposed on protected circuits during surge events. The SMAJ45H maintains this clamping performance across its full operating temperature range.
Is the SMAJ45H suitable for bidirectional transient suppression?
No, the SMAJ45H is a unidirectional TVS diode intended for use with polarity-aware circuits such as 48V supply rails referenced to ground. For bidirectional applications like data line protection or AC-coupled signals, TSC specifies CH or CAH suffix variants (e.g., SMAJ45CH). Using SMAJ45H in reverse-biased configurations may result in premature failure or undefined clamping behavior.
Does the SMAJ45H meet automotive qualification standards?
Yes, the SMAJ45H is AEC-Q101 qualified, having passed stress tests including high-temperature operating life (HTOL), temperature cycling (TCT), and electrostatic discharge (HBM/MM). It also meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements for automotive electrical disturbances - confirming its suitability for engine control units, body electronics, and ADAS power domains.
What is the leakage current specification for the SMAJ45H at its working voltage?
The SMAJ45H specifies a maximum reverse leakage current (IR) of 1 μA when biased at its working stand-off voltage (VWM) of 45 V and measured at TA = 25°C. This ultra-low leakage ensures minimal power loss in always-on vehicle modules and avoids false triggering in high-impedance sensing circuits powered from the same rail protected by the SMAJ45H.
How does the SMAJ45H differ from the SMAJ45AH variant?
The SMAJ45AH features a tighter breakdown voltage range (50.0–55.3 V) versus the SMAJ45H (50.0–61.1 V), resulting in lower typical clamping voltage (72.7 V vs. 80.3 V at 5.5 A). Both share identical package, AEC-Q101 qualification, and ISO 7637-2 compliance. The SMAJ45H offers greater process tolerance for cost-driven applications, while SMAJ45AH targets precision-clamp designs where strict VC ceilings are mandatory.
SMAJ45H 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):
- 45V
- Voltage - Breakdown (Min):
- 50V
- Voltage - Clamping (Max) @ Ipp:
- 80.3V
- Current - Peak Pulse (10/1000µs):
- 5A
- 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)
SMAJ45H FAQ
1.How can I place an order for SMAJ45H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ45H 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 SMAJ45H reliable?
The price and inventory of SMAJ45H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ45H is usually 5 days.
3.What payment methods are accepted for SMAJ45H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ45H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ45H?
SMAJ45H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ45H 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 SMAJ45H?
For technical support, including SMAJ45H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ45H requirements.
6.How does Aetrix verify that SMAJ45H is sourced from the original manufacturer or authorized distributors?
All SMAJ45H 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 SMAJ45H meets industry standards.
7.What is the process for return or replacement of SMAJ45H?
All SMAJ45H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ45H, 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 SMAJ45H part is unused and in its original packaging.
Return procedure for SMAJ45H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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