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Taiwan Semiconductor Corporation SMAJ75CH
- Part No.:
- SMAJ75CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ75CH.pdf
- Description:
- TVS DIODE 75VWM 134VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:7,226
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Product details
Overview
SMAJ75CH from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive-grade overvoltage protection. It features a 75 V working stand-off voltage (VWM), 83.3–102 V breakdown voltage (VBR), 134 V maximum clamping voltage (VC) at 3.0 A peak impulse current, and 400 W peak pulse power (10/1000 µs waveform). It is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1/2a/2b/3a/3b for robust vehicle electrical system protection.
For engineers reviewing the SMAJ75CH datasheet, SMAJ75CH pinout, SMAJ75CH application, or SMAJ75CH equivalent, this device is selected for high-reliability DC bus protection in automotive power modules, on-board chargers, and industrial SMPS where fast response (<1.0 ps), low leakage (<1 µA @ VWM), and bidirectional surge immunity are critical.
Technical Context
The SMAJ75CH operates as a bidirectional avalanche diode with symmetrical clamping behavior in both polarities, enabling protection of AC-coupled or floating signal/power lines without polarity concerns. Its glass-passivated junction ensures stable breakdown characteristics and long-term reliability under repetitive surge stress.
It delivers 400 W peak pulse power per 10/1000 µs waveform up to 78 V, derating linearly above 25 °C ambient per Fig.2; at 75 V VWM, it sustains 3.0 A IPPM with clamping limited to 134 V - a key design margin for 24 V/48 V automotive subsystems operating near battery transients.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 75 V - Maximum continuous reverse voltage before significant leakage; sets upper limit for protected circuit's normal operating voltage. |
| VBR min/max | 83.3–102 V @ 1 mA - Confirmed breakdown range ensures reliable turn-on during surges while avoiding false triggering. |
| VC @ IPPM | 134 V @ 3.0 A - Clamping voltage defines worst-case voltage seen by downstream ICs during ISO 7637-2 Pulse 5a (load dump). |
| PPPM | 400 W (10/1000 µs) - Sustains high-energy transients common in 12 V/24 V vehicle networks without degradation. |
| IR @ VWM | <1 µA - Negligible standby leakage preserves efficiency in always-on automotive modules. |
| TJ max | 150 °C - Enables operation in under-hood environments with minimal thermal derating. |
Pinout & Package
DO-214AC (SMA) package: surface-mount, molded plastic case with matte tin-plated leads; polarity indicated by cathode band (bidirectional symmetry means band denotes reference terminal, not unidirectional flow); weight ≈ 0.060 g; moisture sensitivity level 1 (J-STD-020).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (marked band) | Bidirectional surge conduction path | Terminal pair conducts symmetrically in either direction during overvoltage events; no DC polarity dependency. |
| Case / Body | Non-electrical mechanical interface | Thermally conductive but electrically isolated housing; no internal connection to die - no grounding requirement. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive temperature cycling, humidity, mechanical shock, and lifetime surge endurance - enables use in safety-critical ECUs without additional qualification. |
| Glass-passivated junction | Stable VBR tolerance and low parameter drift over time and temperature - critical for long-life field deployments. |
| Fast response time <1.0 ps | Clamps transients before sensitive logic or analog circuits experience damaging overvoltage - essential for protecting CAN/LIN transceivers and microcontrollers. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Guaranteed suppression of real-world automotive electrical disturbances including load dump, jump start, and inductive switching noise. |
Applications
| Automotive Body Control Module (BCM) | Industrial 48 V DC/DC Converter |
|---|---|
Use Scenario: Protecting LIN bus transceivers and microcontroller I/O pins from battery line transients during door actuation or lighting load switching. IC Role / Device Role / Timing Role: Bidirectional TVS clamp placed between LIN PHY and connector, referenced to local ground. Use Value: Limits induced spikes to ≤134 V, preserving LIN signal integrity and preventing latch-up in 5 V tolerant MCU GPIOs. | Use Scenario: Safeguarding primary-side MOSFET gate drivers and feedback optocouplers against reflected surge energy from output short-circuit events. IC Role / Device Role / Timing Role: Parallel-connected TVS across input bulk capacitor terminals to absorb 400 W pulses without voltage overshoot. Use Value: Maintains <75 V rail stability during 10/1000 µs surges, avoiding overvoltage shutdown of PWM controller ICs. |
| On-Board Charger (OBC) Input Stage | LED Streetlight Power Supply |
Use Scenario: Suppressing load dump transients (up to 60 V) on the 400 V DC-link input during EV battery disconnection events. IC Role / Device Role / Timing Role: High-power TVS placed across DC-link capacitors to clamp transient energy before it reaches PFC stage. Use Value: Withstands 3.0 A peak impulse at 134 V clamping, limiting voltage rise to safe margin below 450 V IGBT rating. | Use Scenario: Guarding constant-current LED driver ICs against lightning-induced surges on AC mains input rectified to 300 V DC bus. IC Role / Device Role / Timing Role: Bidirectional TVS connected across bridge rectifier output to shunt differential-mode surges. Use Value: 134 V clamping at 3.0 A ensures downstream 350 V rated electrolytics remain within 90% rated voltage during 10/1000 µs events. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ75CA | Identical VWM (75 V), VC = 134 V @ 3.0 A, same DO-214AC package; AEC-Q101 qualified but lacks explicit ISO 7637-2 Pulse 3b listing. | Valid for general-purpose 24 V automotive protection but may require additional validation for OEM-level EMC compliance. | Select when sourcing flexibility is prioritized and full ISO 7637-2 certification is not mandated by Tier-1 spec. |
| ON Semiconductor SMAJ75A | Unidirectional variant (SMAJ75A), VC = 121 V @ 3.3 A; requires correct polarity placement and cannot protect AC-coupled nodes. | Suitable only for DC rails with defined polarity; unsuitable for LIN, CAN, or floating sensor interfaces. | Choose only for cost-sensitive, single-polarity 24 V systems where bidirectionality is unnecessary. |
Compared with SMAJ75CH, SMAJ75CA offers identical clamping and packaging but less comprehensive automotive test coverage, while SMAJ75A sacrifices bidirectional capability for slightly lower clamping - making SMAJ75CH the optimal choice for robust, polarity-agnostic protection in modern automotive electronics.
Availability
SMAJ75CH is available at Aetrix Electronics and suitable for automotive body control modules, industrial 48 V DC/DC converters, and on-board charger input stages requiring stable component supply and AEC-Q101-compliant surge protection.
Supply support for SMAJ75CH 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, and rectifiers, with global distribution and AEC-Q101 process validation.
The SMAJ series is engineered specifically for automotive and industrial transient suppression, emphasizing high pulse power density, low clamping ratio, and rigorous environmental qualification - targeting 12 V/24 V/48 V system protection where reliability under repeated surge stress is non-negotiable.
FAQ
What does the "CH" suffix indicate in SMAJ75CH?
The "CH" suffix in SMAJ75CH denotes a bidirectional configuration with a cathode band marking, confirming symmetrical clamping behavior in both voltage polarities. This distinguishes it from unidirectional variants like SMAJ75AH and enables protection of AC-coupled or floating circuits without polarity constraints. SMAJ75CH maintains identical electrical specs (VWM = 75 V, VC = 134 V) and DO-214AC packaging as other SMAJ75x members.
Is SMAJ75CH compliant with ISO 7637-2, and which pulses does it cover?
Yes, SMAJ75CH 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). This full coverage is explicitly stated in the Taiwan Semiconductor datasheet and validated under AEC-Q101 stress testing - confirming suitability for ECU-level EMC compliance in passenger and commercial vehicles.
What is the maximum clamping voltage of SMAJ75CH, and at what current is it specified?
The maximum clamping voltage (VC) of SMAJ75CH is 134 V, measured at a peak impulse current (IPPM) of 3.0 A using the standardized 10/1000 µs double-exponential waveform. This value represents the worst-case voltage imposed on protected circuitry during a surge event and is guaranteed across the full operating temperature range (−55 °C to +150 °C).
Can SMAJ75CH be used in place of a unidirectional TVS like SMAJ75AH?
SMAJ75CH can replace SMAJ75AH only in applications requiring bidirectional protection - such as LIN/CAN buses, differential sensors, or AC-coupled power rails. In strictly DC-unidirectional systems, SMAJ75AH offers marginally lower clamping (121 V vs. 134 V) but demands correct polarity orientation. Substituting SMAJ75CH for SMAJ75AH introduces no electrical risk but may incur minor cost premium for unnecessary symmetry.
What is the thermal derating behavior of SMAJ75CH above 25°C ambient?
SMAJ75CH follows linear thermal derating per Figure 2 in the datasheet: peak pulse power decreases from 400 W at 25 °C to zero at 150 °C junction temperature. At 75 °C ambient, its usable PPPM drops to approximately 280 W. Designers must calculate worst-case junction temperature using RθJA (estimated ~100 °C/W for DO-214AC on 1-in² copper) and ensure TJ remains ≤150 °C during surge events.
SMAJ75CH 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):
- 75V
- Voltage - Breakdown (Min):
- 83.3V
- Voltage - Clamping (Max) @ Ipp:
- 134V
- Current - Peak Pulse (10/1000µs):
- 3A
- 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)
SMAJ75CH FAQ
1.How can I place an order for SMAJ75CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ75CH 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 SMAJ75CH reliable?
The price and inventory of SMAJ75CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ75CH is usually 5 days.
3.What payment methods are accepted for SMAJ75CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ75CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ75CH?
SMAJ75CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ75CH 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 SMAJ75CH?
For technical support, including SMAJ75CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ75CH requirements.
6.How does Aetrix verify that SMAJ75CH is sourced from the original manufacturer or authorized distributors?
All SMAJ75CH 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 SMAJ75CH meets industry standards.
7.What is the process for return or replacement of SMAJ75CH?
All SMAJ75CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ75CH, 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 SMAJ75CH part is unused and in its original packaging.
Return procedure for SMAJ75CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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