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Taiwan Semiconductor Corporation SMAJ75A
- Part No.:
- SMAJ75A
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ75A.pdf
- Description:
- TVS DIODE 75VWM 121VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,888
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Product details
Overview
SMAJ75A from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping fast transients in DC power lines. It features a 75 V working stand-off voltage (VWM), 83.3–92.1 V breakdown voltage (VBR @ 1 mA), 121 V maximum clamping voltage (VC @ 3.3 A), and 400 W peak pulse power (10/1000 µs waveform) - used in automotive power rail protection and industrial DC/DC converters.
For engineers reviewing the SMAJ75A datasheet, SMAJ75A pinout, SMAJ75A application, or SMAJ75A equivalent, this page delivers verified electrical parameters, DO-214AC terminal mapping, ISO 7637-2 compliance status, clamping performance under 10/1000 µs surge, and real-world substitution guidance for robust overvoltage design.
Technical Context
The SMAJ75A operates as a unidirectional avalanche diode with glass-passivated junction, delivering sub-nanosecond response (<1.0 ps from 0 V to VBR min) and low leakage (<1 µA at 75 V). Its thermal design supports continuous operation up to +150 °C junction temperature and meets JESD201 Class 2 whisker resistance.
It is rated for 400 W peak pulse power at TA = 25 °C (derated above ambient), withstands 40 A non-repetitive forward surge (8.3 ms half-sine), and complies with ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive electronics immunity testing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 75 V - Maximum continuous reverse operating voltage before clamping begins; defines safe DC bias margin in protected line. |
| VBR @ IT = 1 mA | 83.3–92.1 V - Breakdown threshold range; ensures reliable turn-on during transients without premature conduction. |
| VC @ IPPM = 3.3 A | 121 V - Clamped voltage under 10/1000 µs surge; determines maximum stress on downstream ICs. |
| PPPM | 400 W - Peak pulse power handling (10/1000 µs); enables protection against high-energy load dump events. |
| IR @ VWM | <1 µA - Reverse leakage at rated stand-off; minimizes quiescent power loss in battery-powered systems. |
| TJ max | +150 °C - Maximum junction temperature; supports operation in under-hood automotive or enclosed industrial enclosures. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-die unidirectional configuration. Cathode indicated by band marking; anode and cathode terminals are axially oriented along the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (A) | Low-side reference node | Connected to ground or return path; completes clamping loop when cathode is tied to protected line. |
| Cathode (K) | Protected line interface | Connected directly to the rail requiring transient suppression (e.g., +12 V battery feed); conducts surge current to ground. |
Key Features
| Feature | Design Value |
|---|---|
| Glass-passivated junction | Ensures stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure. |
| Sub-1 ps response time | Clamps ESD and fast-edge transients before sensitive downstream circuitry experiences overstress. |
| ISO 7637-2 compliance | Validated for automotive load dump (Pulse 2b), supply interruption (Pulse 3b), and coupled transient immunity. |
| Moisture sensitivity level 1 | Enables standard SMT reflow without baking; compatible with automated placement and lead-free assembly. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU Directive 2011/65/EU; suitable for environmentally regulated industrial and automotive programs. |
Applications
| Automotive Power Rail Protection | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting 12 V/24 V battery-fed ECUs from load dump and jump-start surges per ISO 7637-2. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between battery rail and system input filter. Use Value: Limits clamped voltage to 121 V during 400 W transients, preserving upstream fuse coordination and downstream regulator survival. |
Use Scenario: Safeguarding isolated DC/DC converter primary-side inputs against switching noise and back-EMF spikes. IC Role / Device Role / Timing Role: Standoff-clamp device absorbing repetitive 10/1000 µs energy bursts from MOSFET switching nodes. Use Value: Maintains 75 V operational margin while clamping to ≤121 V, enabling use of 150 V-rated input capacitors and FETs. |
| LED Driver Power Stage | Telecom Power Interface |
Use Scenario: Shielding constant-current LED drivers from inductive kickback during dimming or hot-plug events. IC Role / Device Role / Timing Role: Fast-response unidirectional clamp across input bulk capacitor terminals. Use Value: Sub-1 ps turn-on prevents >121 V overshoot that could degrade electrolytic capacitor lifetime or damage driver ICs. |
Use Scenario: Front-end surge protection for 48 V telecom power supplies subjected to lightning-induced surges. IC Role / Device Role / Timing Role: Primary-stage TVS on -48 V input rail, coordinated with MOV and gas discharge tube staging. Use Value: 400 W rating and 121 V clamping enable staged protection architecture meeting IEC 61000-4-5 Level 4 requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ75 (unidirectional, non-A variant) | Higher VBR range (83.3–102 V) and higher VC (134 V @ 3.0 A); same 400 W rating but looser breakdown tolerance. | Less precise clamping; acceptable where 134 V clamping is within downstream IC absolute max ratings. | Select SMAJ75A when tighter VBR control and lower clamping voltage are required for margin-critical designs. |
| SMBJ75A | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; 600 W peak power rating. | Higher power handling and better thermal dissipation; requires larger PCB footprint and different pad layout. | Choose SMBJ75A only if system-level surge testing exceeds 400 W or thermal derating demands lower junction rise. |
Compared with SMAJ75 and SMBJ75A, the SMAJ75A offers optimal balance of precision clamping (±5.3% VBR tolerance), compact DO-214AC footprint, and certified 400 W capability - making it preferred for space-constrained automotive and industrial modules where clamping accuracy and board area are critical.
Availability
SMAJ75A is available at Aetrix Electronics and suitable for automotive ECU protection, industrial DC/DC converter input stages, and LED driver power interfaces requiring stable component supply, full traceability, and long-lifecycle support.
Supply support for SMAJ75A 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, and power devices since 1979.
The SMAJ series is part of TSC's automotive-grade transient suppression portfolio, engineered specifically for ISO 7637-2 compliance and high-reliability DC power line protection in harsh environments.
FAQ
What is the clamping voltage of SMAJ75A under a 10/1000 µs surge?
The SMAJ75A has a maximum clamping voltage (VC) of 121 V when subjected to its rated peak pulse current of 3.3 A using the standardized 10/1000 µs waveform. This value is measured per Figure 5 in the official TSC datasheet (U2102) and defines the upper voltage limit imposed on protected circuitry during surge events.
Is SMAJ75A unidirectional or bidirectional?
SMAJ75A is a unidirectional TVS diode, intended for protection of positive DC rails only. Its cathode band marks the terminal connected to the protected line; polarity reversal would block conduction. For bidirectional protection, TSC specifies SMAJ75CA (with "CA" suffix), not SMAJ75A.
Does SMAJ75A meet automotive surge immunity standards?
Yes, SMAJ75A meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements as explicitly stated in the TSC datasheet. Its 400 W peak pulse rating, fast response, and specified clamping behavior validate its use in automotive power networks including 12 V and 24 V systems.
What is the maximum junction temperature rating for SMAJ75A?
The SMAJ75A has a maximum junction temperature (TJ) rating of +150 °C, confirmed in the Absolute Maximum Ratings table of the TSC datasheet. This allows reliable operation in under-hood automotive locations and sealed industrial enclosures without forced cooling.
What package type does SMAJ75A use, and is it RoHS compliant?
SMAJ75A uses the DO-214AC (SMA) surface-mount package and is fully RoHS compliant and halogen-free per IEC 61249-2-21. The matte tin-plated leads meet J-STD-002 solderability requirements, and moisture sensitivity is rated at Level 1 - enabling standard reflow without pre-baking.
SMAJ75A 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):
- 75V
- Voltage - Breakdown (Min):
- 83.3V
- Voltage - Clamping (Max) @ Ipp:
- 121V
- Current - Peak Pulse (10/1000µs):
- 3.3A
- 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)
SMAJ75A FAQ
1.How can I place an order for SMAJ75A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ75A 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 SMAJ75A reliable?
The price and inventory of SMAJ75A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ75A is usually 5 days.
3.What payment methods are accepted for SMAJ75A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ75A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ75A?
SMAJ75A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ75A 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 SMAJ75A?
For technical support, including SMAJ75A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ75A requirements.
6.How does Aetrix verify that SMAJ75A is sourced from the original manufacturer or authorized distributors?
All SMAJ75A 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 SMAJ75A meets industry standards.
7.What is the process for return or replacement of SMAJ75A?
All SMAJ75A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ75A, 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 SMAJ75A part is unused and in its original packaging.
Return procedure for SMAJ75A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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