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Taiwan Semiconductor Corporation SMAJ8.5CA
- Part No.:
- SMAJ8.5CA
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ8.5CA.pdf
- Description:
- TVS DIODE 8.5VWM 14.4VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,647
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Product details
Overview
SMAJ8.5CA from Taiwan Semiconductor is a bidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for clamping ESD and surge transients in DC power rails and signal lines. It features a 8.5 V working stand-off voltage (VWM), 9.44–10.40 V breakdown voltage (VBR) at 1 mA test current, 14.4 V maximum clamping voltage (VC) at 27.8 A peak impulse current, and 400 W peak pulse power rating with 10/1000 µs waveform.
For engineers reviewing the SMAJ8.5CA datasheet, SMAJ8.5CA pinout, SMAJ8.5CA application, or SMAJ8.5CA equivalent, key selection criteria include clamping performance under ISO 7637-2 Pulse 1/2a/2b/3a/3b, unidirectional vs. bidirectional configuration (CA = bidirectional), moisture sensitivity level (MSL 1), and compatibility with automated SMT placement on industrial power converters and automotive ECUs.
Technical Context
The SMAJ8.5CA employs a glass-passivated silicon junction optimized for fast transient response (<1.0 ps from 0 V to VBR min) and low leakage (<1 µA at 8.5 V). Its bidirectional architecture enables symmetric clamping in AC-coupled or floating-bus applications without polarity constraints.
It operates across –55 °C to +150 °C junction temperature range, supports 40 A non-repetitive forward surge (IFSM), and maintains stable clamping up to 150 °C ambient when derated per Fig.2. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 8.5 V - Maximum continuous reverse voltage before significant leakage; defines safe operating margin below breakdown. |
| VBR min/max | 9.44 V / 10.40 V at IT = 1 mA - Confirmed breakdown threshold range; ensures predictable turn-on during overvoltage events. |
| VC @ IPPM | 14.4 V at 27.8 A - Clamped voltage during 10/1000 µs surge; determines maximum stress imposed on downstream ICs. |
| PPPM | 400 W - Peak pulse power handling capability; validates robustness against automotive load-dump and ISO 7637-2 transients. |
| IR @ VWM | <1 µA - Reverse leakage at rated stand-off voltage; ensures minimal quiescent power loss in battery-powered systems. |
| Package | DO-214AC (SMA) - Standardized surface-mount outline with cathode band marking; compatible with JEDEC MS-013 and IPC-7351B footprints. |
Pinout & Package
DO-214AC (SMA) package: molded plastic case with matte tin-plated leads, polarity indicated by cathode band. Weight ≈ 0.060 g. Complies with J-STD-020 MSL Level 1 (unlimited floor life).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode (unmarked end) | Current entry terminal in forward bias; common reference for bidirectional clamping | Connected to protected line or ground return path; symmetrical conduction enables dual-polarity transient suppression. |
| Cathode (banded end) | Current exit terminal in forward bias; polarity marker for unidirectional variants | Band identifies terminal orientation during automated placement; critical for verifying correct orientation in bidirectional layout (no functional polarity dependence). |
Key Features
| Feature | Design Value |
|---|---|
| Glass passivated junction | Enables stable VBR tolerance and long-term reliability under thermal cycling and humidity exposure. |
| Fast response time <1.0 ps | Clamps transients before sensitive logic or analog circuitry sustains damage; critical for high-speed data lines and microcontroller I/O protection. |
| ISO 7637-2 compliance (Pulse 1/2a/2b/3a/3b) | Validated for automotive 12 V system immunity; supports design to OEM-level EMC requirements without additional filtering. |
| MSL Level 1 rating | Eliminates bake-out requirement prior to reflow; reduces manufacturing cost and avoids moisture-induced popcorning during assembly. |
| Halogen-free & RoHS compliant | Meets IEC 61249-2-21 and EU Directive 2011/65/EU; supports green manufacturing and export compliance for global electronics. |
Applications
| Automotive Body Control Module (BCM) | Industrial DC/DC Converter Input Stage |
|---|---|
Use Scenario: Protects LIN bus transceivers and microcontroller GPIOs from load dump and jump-start transients in vehicle door modules. IC Role / Device Role / Timing Role: Bidirectional TVS clamping element placed directly at connector interface before ESD protection diodes and series impedance. Use Value: Limits induced voltage to ≤14.4 V during 10/1000 µs pulses, preventing latch-up or gate oxide rupture in 5 V tolerant MCU I/O cells. |
Use Scenario: Shields primary-side controller ICs and MOSFET gate drivers from switching noise and input surge in 24 V to 5 V isolated buck converters. IC Role / Device Role / Timing Role: Standoff-clamp protector on VIN rail, coordinated with bulk capacitance and common-mode chokes to meet IEC 61000-4-5 Level 3. Use Value: Absorbs 400 W peak energy without degradation, maintaining <1 µA leakage to avoid standby current drift in always-on power supplies. |
| LED Driver Power Input | USB-C Port VBUS Line Protection |
Use Scenario: Safeguards constant-current LED driver ICs from inductive kickback and hot-plug surges in streetlight and architectural lighting systems. IC Role / Device Role / Timing Role: Primary overvoltage clamp on 12–48 V DC input, positioned upstream of input filter capacitors and PWM controllers. Use Value: Clamps to 14.4 V within picoseconds, preventing overvoltage shutdown or internal regulator failure in integrated LED drivers. |
Use Scenario: Provides secondary-level surge protection on USB-C VBUS after Type-C controller but before PD sink/load switches. IC Role / Device Role / Timing Role: Bidirectional clamp for ±20 V fault conditions (e.g., miswired adapters), co-located with common-mode choke and fuse. Use Value: Delivers symmetrical clamping with <1 µA leakage at 8.5 V, ensuring no impact on USB-C CC logic or VCONN regulation accuracy. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ8.5A (Taiwan Semiconductor) | Unidirectional variant; same VWM/VBR/VC specs but asymmetric conduction (cathode-marked only). | Requires explicit polarity assignment; unsuitable for AC-coupled or floating-bus nodes where voltage polarity reverses. | Select SMAJ8.5A only when protecting unidirectional DC rails with known polarity and no risk of reverse bias. |
| SMBJ8.5CA (ON Semiconductor) | Same VWM (8.5 V), slightly higher VC (15.0 V @ 25.2 A); SMB package (DO-214AA) has larger footprint and 600 W rating. | Higher power handling suits higher-energy transients but requires PCB layout change; not drop-in compatible. | Choose SMBJ8.5CA only if system-level testing shows SMAJ8.5CA clamping margin is insufficient and board space allows DO-214AA footprint. |
Compared with SMAJ8.5A, the SMAJ8.5CA provides polarity-agnostic protection essential for differential buses and floating grounds; compared with SMBJ8.5CA, it offers identical clamping performance in a smaller DO-214AC footprint but with lower absolute energy absorption capacity.
Availability
SMAJ8.5CA is available at Aetrix Electronics and suitable for automotive body electronics, industrial DC/DC converter designs, and LED driver power stages requiring stable component supply with full traceability and lifecycle management.
Supply support for SMAJ8.5CA 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, rectifiers, and MOSFETs for industrial and automotive markets.
The SMAJ series was developed specifically for high-reliability transient suppression in harsh-environment applications, emphasizing MSL Level 1 handling, ISO 7637-2 compliance, and glass-passivated junction stability.
FAQ
What does the 'CA' suffix indicate in SMAJ8.5CA?
The 'CA' suffix in SMAJ8.5CA denotes a bidirectional configuration, meaning the device functions identically in both polarities-clamping positive and negative transients relative to the reference node. Unlike unidirectional 'A' variants (e.g., SMAJ8.5A), SMAJ8.5CA has no designated anode or cathode for functional operation, though the physical cathode band remains for orientation consistency during placement. This makes SMAJ8.5CA ideal for AC-coupled lines, floating grounds, or differential buses where voltage polarity may reverse.
Is SMAJ8.5CA suitable for protecting a 5 V logic rail?
No-SMAJ8.5CA is not recommended for direct protection of a 5 V logic rail because its 8.5 V working stand-off voltage (VWM) exceeds the 5 V supply, allowing transients up to 8.5 V to pass unclamped. For 5 V systems, a lower-VWM device such as SMAJ5.0CA (VWM = 5.0 V) is appropriate. Using SMAJ8.5CA on a 5 V rail risks insufficient clamping during sub-8.5 V overvoltages and may permit damaging energy to reach downstream ICs before the TVS activates.
Does SMAJ8.5CA meet automotive qualification standards?
Yes-SMAJ8.5CA meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b test requirements for 12 V automotive electrical systems, and is rated for operation from –55 °C to +150 °C junction temperature. While it is not AEC-Q200 qualified as a standalone component, its construction (glass-passivated junction, MSL Level 1, JESD201 Class 2 whisker resistance) and tested surge performance align with Tier 1 supplier expectations for non-safety-critical transient suppression in BCMs, lighting modules, and infotainment power supplies.
What is the maximum peak impulse current (IPPM) for SMAJ8.5CA?
The maximum peak impulse current (IPPM) for SMAJ8.5CA is 27.8 A under the standard 10/1000 µs double-exponential surge waveform. This value is derived from its 400 W peak pulse power rating and 14.4 V clamping voltage (VC), calculated as IPPM = PPPM / VC = 400 W / 14.4 V ≈ 27.8 A. This rating applies at TA = 25 °C and must be derated linearly above that ambient temperature per the pulse derating curve in the datasheet (Fig.2).
Can SMAJ8.5CA replace SMAJ8.0CA in an existing design?
Yes-SMAJ8.5CA can replace SMAJ8.0CA in most cases, provided the system's maximum allowable clamping voltage remains within specification. SMAJ8.5CA has a higher VWM (8.5 V vs. 8.0 V) and slightly higher VC (14.4 V vs. 13.6 V), offering improved noise immunity but marginally reduced clamping headroom. Verify that the protected circuit tolerates the 0.8 V higher clamping voltage and that the 8.5 V stand-off still provides adequate margin above normal operating voltage. No PCB changes are needed-the DO-214AC footprint and polarity marking are identical.
SMAJ8.5CA 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):
- 8.5V
- Voltage - Breakdown (Min):
- 9.44V
- Voltage - Clamping (Max) @ Ipp:
- 14.4V
- Current - Peak Pulse (10/1000µs):
- 27.8A
- 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)
SMAJ8.5CA FAQ
1.How can I place an order for SMAJ8.5CA through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ8.5CA 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 SMAJ8.5CA reliable?
The price and inventory of SMAJ8.5CA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ8.5CA is usually 5 days.
3.What payment methods are accepted for SMAJ8.5CA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ8.5CA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ8.5CA?
SMAJ8.5CA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ8.5CA 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 SMAJ8.5CA?
For technical support, including SMAJ8.5CA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ8.5CA requirements.
6.How does Aetrix verify that SMAJ8.5CA is sourced from the original manufacturer or authorized distributors?
All SMAJ8.5CA 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 SMAJ8.5CA meets industry standards.
7.What is the process for return or replacement of SMAJ8.5CA?
All SMAJ8.5CA units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ8.5CA, 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 SMAJ8.5CA part is unused and in its original packaging.
Return procedure for SMAJ8.5CA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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