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Taiwan Semiconductor Corporation SMAJ45CA
- Part No.:
- SMAJ45CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ45CA.pdf
- Description:
- TVS DIODE 45VWM 72.7VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,922
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Product details
Overview
SMAJ45CA from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power lines and signal paths. It features a 45 V working stand-off voltage (VWM), 50.0–61.1 V breakdown voltage (VBR), 72.7 V maximum clamping voltage (VC) at 5.5 A peak pulse current, and 400 W peak pulse power rating per 10/1000 µs waveform - deployed in switching mode power supplies and automotive DC/DC converters.
For engineers reviewing the SMAJ45CA datasheet, SMAJ45CA pinout, SMAJ45CA application, or SMAJ45CA equivalent, this device is selected for high-reliability transient suppression where low clamping ratio, sub-1 ps response time, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, and DO-214AC (SMA) package compatibility are critical design requirements.
Technical Context
The SMAJ45CA is a bipolar (bidirectional) TVS diode with symmetrical avalanche breakdown in both polarities, enabling protection of AC-coupled or floating signal lines without polarity concerns. Its glass-passivated junction ensures stable leakage (<1 µA at VWM) and long-term reliability under repeated surge stress.
It delivers fast transient response (typically <1.0 ps from 0 V to VBR min) and meets automotive-grade surge immunity per ISO 7637-2 across all five defined test pulses. Thermal performance is rated for continuous operation from –55 °C to +150 °C junction temperature, with derated peak power above 25 °C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 45 V - Maximum continuous reverse operating voltage before significant leakage begins; defines safe DC bias margin. |
| VBR @ IT=1 mA | 50.0–61.1 V - Breakdown occurs within this range at 1 mA test current; ensures predictable turn-on threshold. |
| VC @ IPPM=5.5 A | 72.7 V - Clamped voltage during 10/1000 µs surge; limits downstream component stress to ≤72.7 V. |
| PPPM | 400 W - Peak pulse power handling per standard 10/1000 µs waveform; supports high-energy transients. |
| IR @ VWM | <1 µA - Ultra-low reverse leakage at rated stand-off voltage; minimizes standby power loss. |
| Junction Temp Range | –55 °C to +150 °C - Enables deployment in under-hood automotive, industrial, and high-temperature PCB environments. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, bi-directional configuration with cathode band omitted (no polarity marking required).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode / Cathode (symmetrical) | Transient conduction path | Both terminals function identically; bidirectional clamping occurs regardless of voltage polarity applied. |
| Case (body) | Thermal and mechanical interface | DO-214AC molded body provides UL 94V-0 flammability rating and 0.060 g mass for automated placement stability. |
Key Features
| Feature | Design Value |
|---|---|
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive load dump), Pulse 2a/2b (switching transients), and Pulse 3a/3b (capacitive coupling) - enables direct use in automotive ECUs without external filtering. |
| Sub-1 ps response time | Typically <1.0 ps from 0 V to VBR min - clamps ESD and fast-rising transients before sensitive ICs experience overstress. |
| Moisture sensitivity level 1 | Per J-STD-020 - no floor life limitation or bake requirement prior to reflow; simplifies SMT manufacturing flow. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS Directive - satisfies environmental compliance for global electronics markets. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Protection |
|---|---|
Use Scenario: Protects microcontroller GPIOs and CAN transceiver power rails from load-dump spikes and inductive kickback in vehicle door modules and lighting controllers. IC Role / Device Role: Bidirectional clamping element placed between 12 V supply rail and ground, upstream of LDOs and logic ICs. Use Value: Limits transient excursions to ≤72.7 V during ISO 7637-2 Pulse 5a (load dump), preventing latch-up or permanent damage to 5 V/3.3 V logic. |
Use Scenario: Shields 24 V digital input channels on programmable logic controllers from field-wiring surges and relay contact bounce. IC Role / Device Role: Primary overvoltage clamp on each optocoupler input stage, mounted directly at terminal block entry point. Use Value: Withstands ≥5.5 A peak impulse (10/1000 µs) while maintaining <1 µA leakage at 24 V nominal, ensuring clean signal detection and long-term sensor interface integrity. |
| LED Driver Power Stage | USB-C Power Delivery Interface |
Use Scenario: Suppresses switching noise and inductive transients generated by buck/boost LED drivers in architectural and automotive lighting systems. IC Role / Device Role: Parallel-connected TVS across output capacitor terminals to absorb flyback energy from inductor current interruption. Use Value: 400 W peak power rating handles repetitive 10/1000 µs surges up to 500× per hour without degradation, supporting >50,000-hour lifetime requirements. |
Use Scenario: Provides secondary-level surge protection on VBUS lines of USB-C PD sink ports exposed to hot-plug and cable-induced transients. IC Role / Device Role: Secondary clamp after primary common-mode choke and before PD controller's internal overvoltage protection. Use Value: 72.7 V clamping voltage ensures VBUS stays below 75 V absolute maximum rating of most USB-C PD controllers during 1 kV EFT 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 |
|---|---|---|---|
| Littelfuse SMAJ45CA | Identical electrical specs, same DO-214AC package, but marked with different date code format and traceability structure. | No functional difference; validated for identical ISO 7637-2 test profiles and thermal derating curves. | Select when dual-sourcing or lifecycle continuity is required without redesign. |
| ON Semiconductor SMAJ45CA | Same VWM, VBR, VC, and PPPM; minor variation in IR spec (≤1 µA vs ≤0.5 µA at VWM). | Compatible in all SMAJ45CA applications; slight leakage advantage may matter only in ultra-low-power always-on circuits. | Prefer for designs requiring lowest possible standby leakage in battery-backed systems. |
Compared with Littelfuse and ON Semiconductor alternatives, the Taiwan Semiconductor SMAJ45CA offers identical clamping performance and surge rating, with MSL Level 1 handling and full ISO 7637-2 coverage - making it suitable for drop-in qualification in automotive and industrial designs where supply chain diversification is prioritized without compromising protection integrity.
Availability
SMAJ45CA is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC input stages, LED driver power stages, and USB-C power delivery interfaces requiring stable component supply across multi-year production cycles.
Supply support for SMAJ45CA 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 is part of TSC's transient protection product line, engineered specifically for high-reliability DC power line and signal path protection in automotive, industrial, and consumer applications demanding ISO 7637-2 compliance and MSL Level 1 manufacturability.
FAQ
What is the clamping voltage of SMAJ45CA at its rated peak pulse current?
The SMAJ45CA has a maximum clamping voltage (VC) of 72.7 V at 5.5 A peak pulse current (IPPM) under the standard 10/1000 µs waveform. This value is measured per JEDEC test conditions and guarantees that downstream circuitry will not experience voltages exceeding 72.7 V during specified surge events - a key parameter for protecting 5 V or 3.3 V logic interfaces powered from a 45 V rail. The SMAJ45CA maintains this clamping performance across its full operating temperature range.
Is SMAJ45CA unidirectional or bidirectional, and how does that affect its circuit placement?
SMAJ45CA is a bidirectional TVS diode, indicated by the "CA" suffix per manufacturer documentation. It provides symmetrical clamping in both forward and reverse directions, eliminating polarity concerns during layout. Unlike unidirectional variants (e.g., SMAJ45A), SMAJ45CA can be placed across any two nodes - such as differential signal pairs or floating power rails - without regard to anode/cathode orientation. This simplifies routing in space-constrained automotive and industrial PCBs where signal symmetry matters.
Does SMAJ45CA meet automotive surge immunity standards?
Yes, SMAJ45CA meets ISO 7637-2 for all five defined test pulses: Pulse 1 (inductive load dump), Pulse 2a/2b (supply line transients), and Pulse 3a/3b (capacitive coupling). Its 400 W peak pulse power rating, fast <1.0 ps response, and guaranteed clamping behavior under temperature derating make it qualified for use in automotive body electronics, infotainment power supplies, and ADAS sensor interfaces - provided layout follows recommended pad geometry and thermal relief guidelines from the DO-214AC datasheet.
What is the maximum steady-state power dissipation rating for SMAJ45CA?
The SMAJ45CA has a steady-state power dissipation (PD) rating of 1 W at 25 °C ambient, as specified in its Absolute Maximum Ratings table. This value applies to continuous DC or low-frequency reverse-bias conditions - not transient events. In normal operation, reverse leakage remains <1 µA at 45 V, resulting in negligible static power (≤45 µW). The 1 W rating primarily governs thermal design margins during sustained overvoltage or elevated ambient temperatures, and must be derated linearly above 25 °C per the published derating curve.
Can SMAJ45CA be used in place of SMAJ45A in a design?
No - SMAJ45CA and SMAJ45A are not interchangeable without circuit review. SMAJ45CA is bidirectional (suitable for AC or floating lines), while SMAJ45A is unidirectional (anode-to-cathode conduction only). Substituting SMAJ45CA for SMAJ45A introduces unintended conduction paths in DC-biased circuits and may compromise protection effectiveness. Always verify polarity requirements and consult the respective VBR, VC, and IR values in the Taiwan Semiconductor datasheet before substitution - SMAJ45CA is not a drop-in replacement for SMAJ45A.
SMAJ45CA 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:
- 72.7V
- Current - Peak Pulse (10/1000µs):
- 5.5A
- 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)
SMAJ45CA FAQ
1.How can I place an order for SMAJ45CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ45CA 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 SMAJ45CA reliable?
The price and inventory of SMAJ45CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ45CA is usually 5 days.
3.What payment methods are accepted for SMAJ45CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ45CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ45CA?
SMAJ45CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ45CA 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 SMAJ45CA?
For technical support, including SMAJ45CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ45CA requirements.
6.How does Aetrix verify that SMAJ45CA is sourced from the original manufacturer or authorized distributors?
All SMAJ45CA 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 SMAJ45CA meets industry standards.
7.What is the process for return or replacement of SMAJ45CA?
All SMAJ45CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ45CA, 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 SMAJ45CA part is unused and in its original packaging.
Return procedure for SMAJ45CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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