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Taiwan Semiconductor Corporation SMAJ70CA
- Part No.:
- SMAJ70CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ70CA.pdf
- Description:
- TVS DIODE 70VWM 113VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,753
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Product details
Overview
SMAJ70CA from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for robust overvoltage protection in DC power rails. It features a 70 V working stand-off voltage (VWM), 77.8–95.1 V breakdown voltage (VBR @ 1 mA), 125 V maximum clamping voltage (VC @ 3.2 A), and 400 W peak pulse power (10/1000 µs waveform) - deployed in automotive power supplies, industrial DC/DC converters, and lighting drivers.
For engineers reviewing the SMAJ70CA datasheet, SMAJ70CA pinout, SMAJ70CA application, or SMAJ70CA equivalent, key selection criteria include bidirectional clamping capability, ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance, moisture sensitivity level 1 (J-STD-020), and DO-214AC mechanical compatibility with automated SMT placement.
Technical Context
The SMAJ70CA operates as a silicon avalanche diode optimized for fast transient suppression in bidirectional signal and power lines. Its glass-passivated junction ensures stable breakdown characteristics and low leakage (<1 µA at 70 V), while sub-1 ps response time enables effective clamping of ESD and load-dump transients before downstream circuitry is stressed.
Rated for -55°C to +150°C junction temperature, it delivers 400 W peak pulse power up to 25°C (derated linearly above), with clamping performance validated under standardized 10/1000 µs waveform per R.E.A. definition. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for high-reliability PCB mounting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 70 V - Maximum continuous reverse operating voltage before significant leakage; defines safe DC rail margin for 48 V or 60 V systems. |
| VBR min/max | 77.8 V / 95.1 V @ 1 mA - Verified avalanche breakdown range; ensures consistent turn-on across production lots and temperature. |
| VC @ IPPM | 125 V @ 3.2 A - Clamped voltage during 400 W transient; limits stress on protected ICs such as PMICs or microcontrollers. |
| PPPM | 400 W (10/1000 µs) - Peak surge handling capacity; supports automotive load-dump immunity per ISO 7637-2 Pulse 5a. |
| IR @ VWM | <1 µA - Ultra-low reverse leakage at rated stand-off; avoids unnecessary power loss in battery-backed or low-quiescent circuits. |
| TJ max | +150 °C - Maximum junction temperature rating; enables operation in under-hood automotive or enclosed industrial enclosures. |
| Package | DO-214AC (SMA) - Industry-standard surface-mount outline; compatible with IPC-7351B footprint and reflow profiles. |
Pinout & Package
DO-214AC (SMA) package: molded epoxy case with matte tin-plated leads, cathode band marking polarity for unidirectional variants; SMAJ70CA is bidirectional and marked with "RN" code - no polarity dependence in circuit layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bidirectional avalanche junction | Either terminal serves as anode or cathode depending on transient polarity; no orientation required during placement. |
| Case (body) | Non-electrical mechanical interface | Thermally conductive but electrically isolated housing; provides mechanical anchoring and minimal parasitic capacitance (~100 pF typical). |
Key Features
| Feature | Design Value |
|---|---|
| ISO 7637-2 compliance | Validated for Pulse 1 (inductive switch-off), Pulse 2a/2b (battery disconnect/connect), and Pulse 3a/3b (capacitive coupling); eliminates need for external test conditioning. |
| Fast response time | <1.0 ps from 0 V to VBR min - enables clamping before ESD or fast-edge transients propagate into sensitive analog or digital circuitry. |
| Moisture sensitivity level | MSL Level 1 (per J-STD-020) - allows indefinite floor life without dry-pack or baking; simplifies SMT line logistics. |
| RoHS & halogen-free | Compliant with RoHS Directive 2011/65/EU and IEC 61249-2-21 - meets environmental requirements for automotive and industrial end-equipment. |
| Automated placement ready | DO-214AC geometry and lead coplanarity meet IPC-A-610 Class 2/3 standards; supports >99.9% placement yield on high-speed pick-and-place machines. |
Applications
| Automotive Power Supply Protection | Industrial DC/DC Converter Input |
|---|---|
Use Scenario: Protecting 12 V/24 V vehicle electronics against load dump (ISO 7637-2 Pulse 5a) and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional TVS placed at DC input stage of body control module or infotainment head unit. Use Value: Limits transient voltage to ≤125 V during 100 V/350 ms load dump events, preventing latch-up or gate oxide damage in downstream regulators. |
Use Scenario: Safeguarding isolated DC/DC converter primary-side inputs in programmable logic controllers (PLCs) and motor drives. IC Role / Device Role / Timing Role: Standoff protection element absorbing inductive kickback from relay coils or solenoid drivers. Use Value: Withstands 400 W surges without degradation, enabling >100,000 surge cycles per MIL-STD-883H Method 3015.8. |
| LED Driver Overvoltage Clamp | Smart Lighting Bus Interface |
Use Scenario: Preventing catastrophic failure in constant-current LED drivers exposed to lightning-induced surges on AC mains input. IC Role / Device Role / Timing Role: Primary-stage clamping device placed between bridge rectifier output and bulk capacitor. Use Value: Clamps 1 kV/1.2 µs × 50 Ω surge to <125 V within <1 ps, preserving driver IC lifetime and maintaining lumen consistency. |
Use Scenario: Protecting DALI or 0–10 V dimming interfaces from ESD and cable discharge events in commercial lighting networks. IC Role / Device Role / Timing Role: Bidirectional transient suppressor bridging data line to ground on controller-side interface IC. Use Value: Sub-1 µA leakage at 70 V prevents false triggering of low-current bus receivers; MSL Level 1 supports long-term field reliability. |
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 SMAJ70CA | Identical electrical specs, same DO-214AC package, identical marking "RN"; fully interchangeable per Littelfuse datasheet Rev. D. | No functional difference; validated in same automotive and industrial reference designs. | Select for dual-sourcing flexibility where Taiwan Semiconductor allocation is constrained. |
| ON Semiconductor SMAJ70CA | Same VWM, VBR, VC, and PPPM; minor variation in IR spec (≤1 µA vs ≤0.5 µA), otherwise compliant with JEDEC DO-214AC mechanical standard. | Compatible in all SMAJ70CA-designated footprints; slight leakage advantage in ultra-low-power standby circuits. | Prefer when designing for ON Semi's long-term product longevity program or existing BOM consolidation. |
Compared with SMAJ70CA, the Littelfuse and ON Semiconductor alternatives offer identical clamping performance and package compatibility but differ in manufacturing traceability and long-term supply roadmap - Taiwan Semiconductor provides extended lifecycle support for industrial OEMs requiring >10-year availability assurance.
Availability
SMAJ70CA is available at Aetrix Electronics and suitable for automotive power supply protection, industrial DC/DC converter input stages, and LED driver overvoltage clamp applications requiring stable component supply, full MSL Level 1 handling, and ISO 7637-2 validation.
Supply support for SMAJ70CA 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 AEC-Q200 qualified production lines.
The SMAJ series was developed specifically for high-reliability transient suppression in automotive and industrial environments, emphasizing fast response, low leakage, and robust surge endurance under harsh thermal and mechanical conditions.
FAQ
What is the clamping voltage of SMAJ70CA under a 400 W transient?
The SMAJ70CA clamps to a maximum of 125 V when subjected to its rated 400 W peak pulse power (10/1000 µs waveform) at 3.2 A. This value is measured per standardized test conditions in the Taiwan Semiconductor datasheet U2102 and guarantees protection margin for 70 V-rated downstream components. The SMAJ70CA maintains this clamping performance across its full operating temperature range (-55°C to +150°C).
Is SMAJ70CA unidirectional or bidirectional?
SMAJ70CA is a bidirectional transient voltage suppressor, indicated by the "CA" suffix per Taiwan Semiconductor's naming convention. It provides symmetrical clamping in both polarities - essential for protecting AC-coupled lines or floating DC buses where transient polarity is unpredictable. Unlike unidirectional SMAJ70A, the SMAJ70CA does not require orientation during PCB placement.
Does SMAJ70CA meet automotive ESD and surge standards?
Yes, SMAJ70CA meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements for automotive transient immunity, and its sub-1 ps response time supports IEC 61000-4-2 Level 4 ESD protection when used with proper PCB layout. Taiwan Semiconductor validates these capabilities in the U2102 datasheet, confirming suitability for body electronics, infotainment, and ADAS power domains.
What is the maximum steady-state power dissipation of SMAJ70CA?
The SMAJ70CA has a steady-state power dissipation (PD) rating of 1 W at 25°C ambient, as specified in the Absolute Maximum Ratings table. This value applies only to continuous DC or low-frequency reverse bias conditions - the device is not intended for sustained power dissipation but rather for transient energy absorption. For thermal design, derating curves in Figure 2 of the U2102 datasheet must be applied above 25°C.
Can SMAJ70CA replace SMAJ70A in an existing design?
No - SMAJ70CA and SMAJ70A are not functionally interchangeable. SMAJ70A is unidirectional (anode-cathode asymmetric), while SMAJ70CA is bidirectional (symmetric). Replacing one with the other without verifying circuit topology may result in incorrect clamping behavior or forward conduction during normal operation. Always confirm polarity requirements and consult the Taiwan Semiconductor U2102 datasheet before substitution.
SMAJ70CA 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ70CA FAQ
1.How can I place an order for SMAJ70CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ70CA 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 SMAJ70CA reliable?
The price and inventory of SMAJ70CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ70CA is usually 5 days.
3.What payment methods are accepted for SMAJ70CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ70CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ70CA?
SMAJ70CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ70CA 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 SMAJ70CA?
For technical support, including SMAJ70CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ70CA requirements.
6.How does Aetrix verify that SMAJ70CA is sourced from the original manufacturer or authorized distributors?
All SMAJ70CA 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 SMAJ70CA meets industry standards.
7.What is the process for return or replacement of SMAJ70CA?
All SMAJ70CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ70CA, 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 SMAJ70CA part is unused and in its original packaging.
Return procedure for SMAJ70CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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