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Taiwan Semiconductor Corporation SMAJ45C
- Part No.:
- SMAJ45C
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ45C.pdf
- Description:
- 400W, 55.6V, 10%, BIDIRECTIONAL,
- Quantity:
- Payment:
- Shipping:
Inventory:3,968
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Product details
Overview
SMAJ45C from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 45 V working stand-off voltage (VWM), 50.0–61.1 V breakdown voltage (VBR) at 1 mA test current, and clamps transients to ≤80.3 V at 5.0 A peak impulse current under 10/1000 µs waveform - enabling reliable protection of 48 V industrial power supplies and automotive ECUs.
For engineers reviewing the SMAJ45C datasheet, SMAJ45C pinout, SMAJ45C application, or SMAJ45C equivalent, key selection criteria include its DO-214AC (SMA) package compatibility with automated SMT assembly, sub-1 ps response time, <1 µA reverse leakage above VWM, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, and 400 W peak pulse power rating at TA = 25°C.
Technical Context
The SMAJ45C operates as a unidirectional avalanche diode, leveraging glass-passivated junction technology to achieve fast turn-on (<1 ps from 0 V to VBR min) and stable clamping under repetitive surge events. Its single-die DO-214AC construction supports high surge current handling while maintaining low junction capacitance - critical for protecting sensitive analog and digital interfaces without signal distortion.
Thermal derating follows a defined curve (Fig.2), reducing peak pulse power linearly above 25°C ambient; maximum junction temperature is rated at +150°C, with storage range from –55°C to +150°C. Polarity is marked by a cathode band, and terminals are matte tin-plated for J-STD-002 solderability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45 V - Maximum continuous DC or RMS voltage the device blocks without conduction |
| VBR min/max | 50.0 / 61.1 V @ 1 mA - Ensures predictable avalanche initiation across production lot |
| VC @ IPPM | ≤80.3 V @ 5.0 A (10/1000 µs) - Defines worst-case clamped voltage seen by protected circuitry |
| PPPM | 400 W (10/1000 µs, TA = 25°C) - Supports IEC/ISO surge immunity testing up to Level 4 |
| IR @ VWM | ≤1 µA - Minimizes standby power loss and avoids false triggering in high-impedance nodes |
| Package | DO-214AC (SMA) - Industry-standard SMT footprint compatible with IPC-7351B land pattern |
Pinout & Package
DO-214AC (SMA) package: surface-mount, molded plastic case with cathode band marking; dimensions per JEDEC DO-214AC standard; weight ≈ 0.060 g; UL 94V-0 rated molding compound.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side reference terminal | Connected to ground or lowest potential node in unidirectional configuration |
| Cathode | Protected line input | Connected to line being protected (e.g., 48 V rail); cathode band identifies this terminal |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Enables stable VBR tolerance and long-term reliability under thermal cycling and humidity stress |
| Response time <1 ps | Clamps ESD and fast transients before downstream ICs experience overstress |
| ISO 7637-2 compliance | Validated for automotive load dump (Pulse 2b), battery disconnect (Pulse 3b), and coupled noise immunity |
| J-STD-020 Level 1 moisture sensitivity | Allows unlimited floor life and reflow without baking preconditioning |
| RoHS & halogen-free | Meets IEC 61249-2-21 and EU Directive 2011/65/EU for environmentally constrained applications |
Applications
| Industrial Power Supply Protection | Automotive Body Control Module |
|---|---|
Use Scenario: Protecting 48 V DC input stage of DIN-rail mounted PLC power modules against load dump and inductive switching spikes. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between input rail and chassis ground, acting as primary clamping element in multi-stage protection scheme. Use Value: Limits transient voltage to ≤80.3 V during 400 W surges, preventing damage to upstream rectifiers and downstream DC/DC controllers. |
Use Scenario: Safeguarding LIN bus transceivers and microcontroller I/O pins in door module ECUs exposed to battery voltage fluctuations and ESD. IC Role / Device Role / Timing Role: Standoff-rated TVS on 12 V supply rail and signal lines, providing fast-response clamping without loading normal operation. Use Value: Sub-1 ps response ensures clamping occurs before LIN transceiver's absolute maximum ratings are exceeded during ISO 10605 ESD events. |
| LED Driver Input Stage | Telecom DC Power Interface |
Use Scenario: Overvoltage protection for constant-current LED drivers used in street lighting, subject to lightning-induced surges on AC-DC front-end outputs. IC Role / Device Role / Timing Role: Secondary TVS on isolated 48 V output rail, coordinated with primary MOV and fuse for staged energy absorption. Use Value: 400 W peak pulse rating handles residual energy after upstream suppression, ensuring driver ICs survive repeated 10/1000 µs transients. |
Use Scenario: Protecting -48 V telecom power feed interface in remote radio units against accidental polarity reversal and induced surges from nearby lightning strikes. IC Role / Device Role / Timing Role: Unidirectional TVS connected anode-to-ground, clamping positive excursions on negative supply rail. Use Value: 45 V VWM allows safe operation across full -48 V ±10% tolerance range while clamping to <81 V during surge events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ45A | Narrower VBR range (50.0–55.3 V) and lower VC (≤72.7 V @ 5.5 A); tighter tolerance improves clamping consistency | Better suited for precision 48 V systems where clamping margin below 75 V is required | Select SMAJ45A when lower clamping voltage and tighter VBR distribution are prioritized over cost |
| SMBJ45C | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; higher thermal mass enables better derating above 25°C | Preferred for high-temperature environments (>85°C ambient) or higher average surge duty cycles | Choose SMBJ45C when board space permits and thermal performance under sustained surge conditions is critical |
Compared with SMAJ45C, SMAJ45A offers improved clamping precision at the expense of slightly reduced surge current headroom, while SMBJ45C trades smaller footprint for superior thermal resilience - making SMAJ45C the optimal balance of size, performance, and manufacturability for standard 48 V industrial designs.
Availability
SMAJ45C is available at Aetrix Electronics and suitable for industrial power supply protection, automotive body control modules, LED driver input stages, and telecom DC power interfaces requiring stable component supply and consistent surge immunity performance.
Supply support for SMAJ45C 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 consumer applications.
The SMAJ series was developed specifically for high-reliability, surface-mount transient suppression in harsh environments - emphasizing fast response, ISO 7637-2 compliance, and robust packaging for automated manufacturing.
FAQ
What is the polarity configuration of SMAJ45C?
The SMAJ45C is a unidirectional TVS diode, with cathode identified by a band on the DO-214AC package. It conducts only during positive transients on the cathode relative to anode - making it suitable for protecting positive DC rails like 48 V systems. This differs from bidirectional variants (e.g., SMAJ45CA), which suppress both polarities.
Does SMAJ45C meet automotive surge immunity standards?
Yes, SMAJ45C meets ISO 7637-2 requirements for Pulse 1 (inductive load disconnect), Pulse 2a (sudden load removal), Pulse 2b (supply interruption), Pulse 3a (capacitive coupling), and Pulse 3b (ground noise). Its 400 W peak pulse rating and fast response ensure compliance in 12 V and 48 V vehicle networks.
What is the maximum clamping voltage of SMAJ45C under surge conditions?
The SMAJ45C clamps to a maximum of 80.3 V when subjected to a 5.0 A peak impulse current with a 10/1000 µs waveform. This value is guaranteed across the operating temperature range and defines the upper voltage limit imposed on protected circuitry during transient events.
Can SMAJ45C be used in bidirectional protection applications?
No - SMAJ45C is strictly unidirectional. For bidirectional protection, the SMAJ45CA variant must be used. Using SMAJ45C in reverse-biased configurations risks permanent failure due to lack of reverse avalanche capability; its datasheet explicitly specifies unidirectional operation only.
What is the moisture sensitivity level (MSL) and reflow profile for SMAJ45C?
SMAJ45C is rated MSL Level 1 per J-STD-020, meaning it has unlimited floor life and may be reflowed using standard Pb-free or SnPb profiles without pre-baking. Its matte tin-plated leads comply with J-STD-002 for solderability, supporting both wave and reflow soldering processes.
SMAJ45C 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):
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ45C FAQ
1.How can I place an order for SMAJ45C through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ45C 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 SMAJ45C reliable?
The price and inventory of SMAJ45C are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ45C is usually 5 days.
3.What payment methods are accepted for SMAJ45C?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ45C transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ45C?
SMAJ45C orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ45C 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 SMAJ45C?
For technical support, including SMAJ45C datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ45C requirements.
6.How does Aetrix verify that SMAJ45C is sourced from the original manufacturer or authorized distributors?
All SMAJ45C 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 SMAJ45C meets industry standards.
7.What is the process for return or replacement of SMAJ45C?
All SMAJ45C units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ45C, 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 SMAJ45C part is unused and in its original packaging.
Return procedure for SMAJ45C:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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