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Taiwan Semiconductor Corporation SMAJ8.5AH
- Part No.:
- SMAJ8.5AH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ8.5AH.pdf
- Description:
- 400W, 9.9V, UNIDIRECTIONAL, TVS
- Quantity:
- Payment:
- Shipping:
Inventory:9,968
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Product details
Overview
SMAJ8.5AH 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 9.44–10.40 V breakdown voltage (VBR), 8.5 V working stand-off voltage (VWM), 14.4 V maximum clamping voltage (VC) at 10 A peak pulse current, and 400 W peak pulse power rating with 10/1000 µs waveform - suitable for automotive-grade DC/DC converter input protection.
For engineers reviewing the SMAJ8.5AH datasheet, SMAJ8.5AH pinout, SMAJ8.5AH application, or SMAJ8.5AH equivalent, key selection criteria include clamping voltage margin relative to system rail, leakage current at operating voltage, AEC-Q101 qualification status, ISO 7637-2 pulse immunity compliance, and DO-214AC thermal and layout compatibility.
Technical Context
The SMAJ8.5AH operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified VBR range (9.44–10.40 V at 1 mA test current). Its glass-passivated junction ensures stable breakdown behavior and low leakage (<1 µA at 8.5 V).
It delivers sub-1 ps response time from 0 V to VBR min, clamps transients to ≤14.4 V at 10 A IPPM under 10/1000 µs waveform, and sustains 150 °C maximum junction temperature - enabling robust protection in automotive and industrial 12 V supply rails subject to load dump and inductive switching events.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 8.5 V - Maximum continuous reverse operating voltage before conduction begins; sets upper limit for safe DC rail operation. |
| VBR @ IT=1 mA | 9.44–10.40 V - Confirmed breakdown threshold range; ensures reliable triggering above nominal 8.5 V rail. |
| VC @ IPPM=10 A | 14.4 V - Clamped voltage during 10/1000 µs surge; defines worst-case overvoltage seen by downstream ICs. |
| IR @ VWM | <1 µA - Ultra-low reverse leakage at rated stand-off voltage; avoids parasitic loading on sensitive 12 V monitoring circuits. |
| PPPM | 400 W - Peak pulse power handling per 10/1000 µs waveform; supports ISO 7637-2 Pulse 1 (inductive switch-off) and Pulse 2a (battery disconnect) immunity. |
| TJ max | 150 °C - Maximum junction temperature; enables operation in under-hood automotive environments without derating at full power. |
| AEC-Q101 | Qualified - Validated for automotive electronic systems per stress-test requirements including HTOL, TCT, and ESD. |
Pinout & Package
DO-214AC (SMA) surface-mount package with cathode band marking; matte tin-plated leads compliant with J-STD-002 solderability and JESD 201 Class 2 whisker resistance; moisture sensitivity level 1 per J-STD-020.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal (cathode-banded side is cathode) | Connected to ground or lower-potential node in unidirectional configuration; defines current path during transient clamp. |
| Cathode | Reverse-biased terminal (marked with band) | Connected to protected line (e.g., 12 V rail); avalanche conduction occurs here during overvoltage events. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive electronics per stress-test protocols - eliminates need for additional reliability screening in Tier-1 BOMs. |
| Glass-passivated junction | Ensures stable VBR tolerance and low parametric drift across temperature and lifetime - critical for long-term field reliability. |
| Sub-1 ps response time | Enables clamping before transient energy couples into downstream circuitry - protects high-speed logic and analog sensors from ESD/EFT. |
| ISO 7637-2 compliance | Meets Pulse 1 (inductive spike), Pulse 2a (battery disconnect), Pulse 2b (alternator load dump), and Pulses 3a/3b (switching noise) - covers full automotive EMC test suite. |
| Halogen-free & RoHS | Complies with IEC 61249-2-21 and EU RoHS Directive - supports green manufacturing and export compliance without material substitution. |
Applications
| Automotive Body Control Module (BCM) | Industrial PLC Digital Input Stage |
|---|---|
Use Scenario: Protecting 12 V CAN/LIN bus power inputs against load dump and alternator ripple in vehicle body control units. IC Role / Device Role / Timing Role: Unidirectional TVS placed between fused 12 V rail and local LDO input to absorb >400 W transients within nanoseconds. Use Value: Limits clamped voltage to 14.4 V - safely below 16 V absolute maximum rating of typical 12 V-input PMICs and CAN transceivers. |
Use Scenario: Safeguarding 24 V digital input channels in programmable logic controllers exposed to relay coil flyback and field wiring surges. IC Role / Device Role / Timing Role: Standoff-rated TVS on each optocoupler input leg to shunt induced transients before signal conditioning circuitry. Use Value: Sub-1 µA leakage at 24 V stand-off ensures minimal impact on current-sense thresholds; DO-214AC footprint allows dense channel spacing. |
| LED Driver Power Supply Input | On-Board DC/DC Converter Protection |
Use Scenario: Suppressing switching noise and inductive kickback on primary-side input of constant-current LED drivers used in automotive lighting. IC Role / Device Role / Timing Role: Primary-side TVS parallel to bulk capacitor to clamp fast-rising transients from MOSFET switching and external ESD events. Use Value: 14.4 V clamping prevents overvoltage stress on bridge rectifier and controller ICs rated for 16–20 V maximum input. |
Use Scenario: Securing 5 V or 3.3 V point-of-load (POL) DC/DC converter inputs in automotive infotainment head units against battery line disturbances. IC Role / Device Role / Timing Role: Secondary-side TVS on POL input rail to complement upstream filtering and meet OEM EMC requirements. Use Value: AEC-Q101 qualification and ISO 7637-2 Pulse 1/2a/2b coverage ensure compliance without additional board-level protection components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ8.5H | Higher VBR range (9.44–11.50 V); higher VC = 15.9 V at 10 A; same package and PPPM. | Less margin between VWM and VBR; less precise clamping for tight 12 V rail designs. | Select SMAJ8.5H only if higher VBR tolerance is acceptable and clamping voltage margin is relaxed. |
| SMBJ8.5AH | Same VWM/VBR/VC specs but in larger DO-214AA (SMB) package; 600 W PPPM rating. | Requires larger PCB area; better thermal dissipation for repetitive surge scenarios. | Choose SMBJ8.5AH when higher surge repetition rate or extended thermal margin is required; not drop-in compatible due to footprint change. |
Compared with SMAJ8.5H and SMBJ8.5AH, the SMAJ8.5AH offers tighter VBR tolerance and lower clamping voltage in the standard DO-214AC footprint - optimizing space-constrained automotive modules where precise 12 V rail protection is critical.
Availability
SMAJ8.5AH is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC digital inputs, and LED driver power supplies requiring stable component supply with AEC-Q101 validation and ISO 7637-2 compliance.
Supply support for SMAJ8.5AH 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 automotive 12 V/24 V systems, emphasizing low clamping voltage, fast response, and robust packaging for under-hood deployment.
FAQ
What is the maximum clamping voltage of the SMAJ8.5AH under standard test conditions?
The SMAJ8.5AH has a maximum clamping voltage (VC) of 14.4 V when subjected to a 10 A peak pulse current with a 10/1000 µs waveform at TA = 25 °C. This value is measured per JEDEC standards and reflects worst-case overvoltage seen by protected circuitry during surge events - critical for ensuring downstream ICs remain within their absolute maximum ratings.
Is the SMAJ8.5AH qualified for automotive applications?
Yes, the SMAJ8.5AH is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b requirements. It is explicitly designed for automotive use cases including body control modules, infotainment power rails, and lighting drivers - with validated performance across -55 °C to +150 °C junction temperature range and humidity-resistant packaging.
How does the SMAJ8.5AH differ from the SMAJ8.5H variant?
The SMAJ8.5AH has a tighter breakdown voltage range (9.44–10.40 V vs. 9.44–11.50 V for SMAJ8.5H) and lower clamping voltage (14.4 V vs. 15.9 V at 10 A). This results in improved overvoltage margin for 12 V systems and more predictable turn-on behavior - making SMAJ8.5AH preferable for designs requiring precise clamping control and reduced stress on downstream components.
What is the reverse leakage current specification for the SMAJ8.5AH at its working voltage?
The SMAJ8.5AH exhibits a maximum reverse leakage current (IR) of less than 1 µA when biased at its rated working stand-off voltage of 8.5 V. This ultra-low leakage ensures minimal power loss and avoids false triggering in high-impedance sensing or monitoring circuits commonly found in automotive and industrial control applications.
Can the SMAJ8.5AH be used in bidirectional configurations?
No, the SMAJ8.5AH is a unidirectional TVS diode and must be used with correct polarity - cathode connected to the protected line. For bidirectional protection, Taiwan Semiconductor specifies CH or CAH suffix variants (e.g., SMAJ8.5CH); using SMAJ8.5AH in reverse-biased mode beyond its specified VWM will result in premature conduction and potential failure.
SMAJ8.5AH Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Taiwan Semiconductor Corporation
- Package/Case:
- DO-214AC, SMA
- Series:
- -
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- 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:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ8.5AH FAQ
1.How can I place an order for SMAJ8.5AH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ8.5AH 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 SMAJ8.5AH reliable?
The price and inventory of SMAJ8.5AH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ8.5AH is usually 5 days.
3.What payment methods are accepted for SMAJ8.5AH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ8.5AH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ8.5AH?
SMAJ8.5AH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ8.5AH 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 SMAJ8.5AH?
For technical support, including SMAJ8.5AH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ8.5AH requirements.
6.How does Aetrix verify that SMAJ8.5AH is sourced from the original manufacturer or authorized distributors?
All SMAJ8.5AH 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 SMAJ8.5AH meets industry standards.
7.What is the process for return or replacement of SMAJ8.5AH?
All SMAJ8.5AH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ8.5AH, 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 SMAJ8.5AH part is unused and in its original packaging.
Return procedure for SMAJ8.5AH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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