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Taiwan Semiconductor Corporation SMAJ70CAH
- Part No.:
- SMAJ70CAH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ70CAH.pdf
- Description:
- TVS DIODE 70VWM 113VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,100
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Product details
Overview
SMAJ70CAH from Taiwan Semiconductor is a bidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive-grade surge protection with 70V working stand-off voltage, 77.8–86.0V breakdown voltage at 1mA, and 113V clamping voltage at 3.5A peak pulse current. It protects DC/DC converters and power supplies against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ70CAH datasheet, SMAJ70CAH pinout, SMAJ70CAH application, or SMAJ70CAH equivalent, this device delivers AEC-Q101 qualified surge immunity, sub-1ps response time, <1µA reverse leakage above 70V, and robust 150°C junction operation - critical for automotive infotainment power rails and on-board charger interfaces.
Technical Context
SMAJ70CAH is a bidirectional TVS diode configured as a single die in a glass-passivated DO-214AC package, with cathode band marking indicating polarity. Its clamping action begins at 77.8V (min VBR) and limits transient energy to ≤113V at 3.5A (IPPM) under 10/1000µs waveform.
The device meets ISO 7637-2 for automotive electrical disturbances and supports continuous operation from –55°C to +150°C. Its 1W steady-state power dissipation and 40A IFSM rating enable resilience against repetitive surges and line faults without thermal runaway.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 70 V - Maximum continuous reverse operating voltage before conduction begins; defines safe DC bias margin for 70V nominal systems. |
| VBR @ IT=1mA | 77.8–86.0 V - Breakdown voltage range confirming reliable turn-on threshold across production lot; ensures consistent clamping onset. |
| VC @ IPPM=3.5A | 113 V - Clamped voltage during 10/1000µs surge; determines maximum stress imposed on downstream ICs like PMICs or microcontrollers. |
| PPPM | 400 W - Peak pulse power handling per 10/1000µs waveform; enables suppression of high-energy load-dump transients in 12V/24V vehicle architectures. |
| IR @ VWM | <1 µA - Reverse leakage at rated stand-off voltage; minimizes quiescent power loss in always-on automotive modules. |
| TJ max | +150 °C - Maximum junction temperature; supports placement near heat-generating components in engine bay or powertrain ECUs. |
Pinout & Package
DO-214AC (SMA) surface-mount package with matte tin-plated leads, UL 94V-0 molding compound, and cathode band marking for polarity identification. Weight: 0.060g. Moisture sensitivity level: J-STD-020 Level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Transient current sink (bidirectional) | Conducts surge current in either direction when voltage exceeds VBR; connects to protected line (e.g., CAN_H or 12V rail). |
| Cathode (banded end) | Transient current sink (bidirectional) | Same functional role as anode due to bidirectional symmetry; no DC polarity dependency - used for differential or AC-coupled protection. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive underhood and cabin applications including temperature cycling, humidity, and mechanical shock per JESD22 standards. |
| Sub-1ps response time | Clamps transients before sensitive logic or analog circuits experience overvoltage - critical for protecting high-speed communication lines. |
| ISO 7637-2 compliance | Withstands defined automotive transient waveforms (Pulse 1, 2a, 2b, 3a, 3b) without degradation - eliminates need for external filtering stages. |
| Glass-passivated junction | Enhances long-term reliability and stability of VBR and leakage under thermal stress and humidity exposure. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU RoHS directives - supports sustainable manufacturing and end-of-life recycling requirements. |
Applications
| Automotive Infotainment Power Rail | On-Board DC/DC Converter Input |
|---|---|
Use Scenario: Protects 12V input to display controller or audio amplifier from battery line transients during cold crank or load dump. IC Role / Device Role / Timing Role: Bidirectional clamping device placed between input rail and ground, absorbing energy before it reaches LDOs or buck controllers. Use Value: Limits voltage excursion to ≤113V during ISO 7637-2 Pulse 2b (100V/100ms), preventing latch-up or permanent damage to 16V-rated input stages. |
Use Scenario: Shields primary-side MOSFET gate drivers and PWM controllers in 48V-to-12V buck converters from coupled noise and switching spikes. IC Role / Device Role / Timing Role: Fast-reacting shunt element that clamps overshoots within 1ps, preserving timing integrity of gate drive signals. Use Value: Maintains stable 12V output by preventing >113V excursions that would trigger overvoltage shutdown in secondary-side monitoring ICs. |
| LED Headlamp Driver Module | Body Control Module (BCM) Power Input |
Use Scenario: Guards constant-current LED driver ICs against alternator-induced surges and ESD events during assembly or service. IC Role / Device Role / Timing Role: Standoff protector mounted directly at connector entry point, conducting only during transients >77.8V. Use Value: Enables use of lower-voltage, cost-optimized driver ICs (e.g., 80V-rated) while maintaining system-level ISO 16750-2 compliance. |
Use Scenario: Secures 5V/3.3V regulator inputs in BCMs exposed to shared chassis ground noise and relay coil flyback. IC Role / Device Role / Timing Role: Low-leakage (<1µA) bidirectional clamp ensuring minimal standby current drain while providing fast transient suppression. Use Value: Extends battery life in key-off states and prevents false resets caused by sub-100ns spikes coupling into microcontroller supply pins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Littelfuse SMAJ70CA | Identical VWM, VBR, and VC specs; same DO-214AC package but not AEC-Q101 qualified. | Lacks automotive qualification - suitable for industrial or consumer power supplies where AEC-Q101 is not mandated. | Select SMAJ70CA only if automotive qualification is unnecessary and cost optimization is prioritized. |
| Vishay SMAJ70CA-E3/5AT | Same electrical parameters and AEC-Q101 qualification; differs in moisture sensitivity level (MSL 1 vs MSL 2a) and tape/reel packaging (7500 vs 3000 pcs/reel). | Compatible for drop-in replacement in automated SMT lines, but requires revalidation of humidity bake process if MSL 2a handling is implemented. | Choose SMAJ70CA-E3/5AT when sourcing from Vishay's authorized distribution channel and MSL 2a compliance is acceptable. |
Compared with SMAJ70CAH, SMAJ70CA lacks AEC-Q101 validation and may require additional system-level qualification for automotive use, while SMAJ70CA-E3/5AT offers identical performance with minor packaging and handling differences - making SMAJ70CAH the preferred choice for new automotive designs requiring full traceability and MSL 1 assurance.
Availability
SMAJ70CAH is available at Aetrix Electronics and suitable for automotive infotainment systems, on-board DC/DC converters, and LED lighting modules requiring stable component supply with full AEC-Q101 documentation and traceable lot history.
Supply support for SMAJ70CAH 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 automotive and industrial certifications.
The SMAJ series was developed specifically for AEC-Q101-compliant transient suppression in 12V/24V automotive subsystems, emphasizing fast response, low leakage, and robust thermal performance under harsh environmental conditions.
FAQ
What does the 'CA' suffix indicate in SMAJ70CAH?
The 'CA' suffix in SMAJ70CAH denotes a bidirectional configuration - meaning the device provides symmetrical clamping in both forward and reverse directions. This is essential for protecting differential signal lines or AC-coupled rails where polarity is undefined. Unlike unidirectional variants (e.g., SMAJ70AH), SMAJ70CAH has no inherent anode/cathode orientation for surge conduction.
Is SMAJ70CAH compatible with lead-free reflow soldering processes?
Yes, SMAJ70CAH supports lead-free reflow soldering per J-STD-020 Level 1 moisture sensitivity classification. Its matte tin-plated leads are solderable per J-STD-002, and the UL 94V-0 molding compound withstands peak temperatures up to 260°C. No pre-bake is required prior to assembly.
How does SMAJ70CAH perform under repeated transient stress?
SMAJ70CAH is rated for non-repetitive 10/1000µs pulses per Fig.5, with derating above 25°C per Fig.2. While not specified for repetitive surges, its 1W steady-state power dissipation and 150°C TJ max allow limited repetition if thermal management ensures junction temperature remains below limit - verified via thermal simulation in actual PCB layout.
Can SMAJ70CAH replace SMAJ70AH in an existing design?
No - SMAJ70AH is unidirectional and requires correct polarity alignment; SMAJ70CAH is bidirectional and lacks polarity dependence. Substituting SMAJ70CAH for SMAJ70AH may cause unintended conduction in DC-biased circuits. Only replace if the circuit is inherently symmetric (e.g., differential bus lines) and layout accommodates bidirectional behavior.
What is the maximum clamping voltage of SMAJ70CAH at its rated peak pulse current?
The maximum clamping voltage of SMAJ70CAH is 113 V at 3.5 A peak pulse current (IPPM) under the standard 10/1000µs waveform. This value is guaranteed across the full operating temperature range and ensures downstream components see no more than 113 V during worst-case transients - a key parameter for selecting downstream IC voltage ratings.
SMAJ70CAH 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):
- 70V
- Voltage - Breakdown (Min):
- 77.8V
- Voltage - Clamping (Max) @ Ipp:
- 113V
- Current - Peak Pulse (10/1000µs):
- 3.5A
- 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)
SMAJ70CAH FAQ
1.How can I place an order for SMAJ70CAH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ70CAH 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 SMAJ70CAH reliable?
The price and inventory of SMAJ70CAH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ70CAH is usually 5 days.
3.What payment methods are accepted for SMAJ70CAH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ70CAH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ70CAH?
SMAJ70CAH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ70CAH 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 SMAJ70CAH?
For technical support, including SMAJ70CAH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ70CAH requirements.
6.How does Aetrix verify that SMAJ70CAH is sourced from the original manufacturer or authorized distributors?
All SMAJ70CAH 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 SMAJ70CAH meets industry standards.
7.What is the process for return or replacement of SMAJ70CAH?
All SMAJ70CAH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ70CAH, 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 SMAJ70CAH part is unused and in its original packaging.
Return procedure for SMAJ70CAH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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