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Taiwan Semiconductor Corporation SMAJ8.5H
- Part No.:
- SMAJ8.5H
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ8.5H.pdf
- Description:
- 400W, 10.5V, UNIDIRECTIONAL, TVS
- Quantity:
- Payment:
- Shipping:
Inventory:5,075
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Product details
Overview
SMAJ8.5H from Taiwan Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode designed for robust overvoltage protection in DC power rails and signal lines. It features a 8.5V working stand-off voltage (VWM), 9.44–11.50V breakdown voltage (VBR @ 1mA), 15.9V maximum clamping voltage (VC) at 10A peak pulse current, and 400W peak pulse power rating (10/1000μs waveform). It is widely deployed in automotive-grade DC/DC converters and industrial adapters.
For engineers reviewing the SMAJ8.5H datasheet, SMAJ8.5H pinout, SMAJ8.5H application, or SMAJ8.5H equivalent, key selection criteria include its AEC-Q101 qualification, DO-214AC (SMA) package compatibility, low 1μA reverse leakage at VWM, sub-1ps response time, and ISO 7637-2 Pulse 1/2a/2b/3a/3b compliance for automotive transient immunity.
Technical Context
The SMAJ8.5H operates as a unidirectional avalanche diode with glass-passivated junction, optimized for fast clamping of ESD and surge transients on low-voltage DC lines. Its electrical behavior follows standard TVS I-V characteristics: negligible leakage below VWM (8.5V), sharp transition into avalanche conduction at VBR (min 9.44V), and stable clamping at ≤15.9V up to 10A IPPM.
It is rated for 150°C maximum junction temperature and supports bidirectional use only when specified with CH or CAH suffix - not applicable to SMAJ8.5H. The device meets JESD201 Class 2 whisker resistance and UL 94V-0 flammability requirements for its DO-214AC molding compound.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 8.5 V - Maximum continuous reverse operating voltage before significant leakage begins; sets upper limit for protected circuit's nominal DC rail. |
| VBR @ IT=1mA | 9.44–11.50 V - Breakdown onset range; ensures reliable triggering above system noise while avoiding false trips during normal operation. |
| VC @ IPPM=10A | 15.9 V - Clamped voltage under 10/1000μs surge; defines worst-case overvoltage seen by downstream ICs during transient events. |
| PPPM | 400 W - Peak pulse power handling (10/1000μs); enables protection against high-energy transients like load dump or inductive switching spikes. |
| IR @ VWM | <1 μA - Reverse leakage at stand-off voltage; minimizes quiescent power loss and avoids interference with high-impedance sensing circuits. |
| Response time | <1.0 ps - Time from 0 V to VBR,min; ensures suppression occurs before sensitive logic or analog components experience overstress. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with cathode band marking. Matte tin-plated leads, RoHS and halogen-free compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Input/Line side for unidirectional clamp | Connected to protected line (e.g., +12V rail); conducts during positive transients when cathode is referenced to ground. |
| Cathode | Ground reference / Clamp return | Connected to system ground or low-impedance return path; establishes clamping threshold relative to reference plane. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualified | Validated for automotive underhood and powertrain applications per stress test conditions including temperature cycling, HTRB, and ESD. |
| Glass passivated junction | Enhances long-term reliability and moisture resistance vs. epoxy-passivated alternatives; critical for industrial environments with thermal cycling. |
| ISO 7637-2 compliance | Withstands standardized automotive transients (Pulse 1: inductive load disconnect; Pulse 2a: relay switch-off; Pulse 3a/b: capacitive coupling), enabling drop-in use in vehicle ECUs. |
| Moisture sensitivity level 1 | No floor life limitation or bake requirement prior to reflow; simplifies SMT assembly and reduces manufacturing overhead. |
Applications
| Automotive DC/DC Converters | Industrial SMPS Input Protection |
|---|---|
Use Scenario: Protecting 5–12V output rails of buck converters in engine control units (ECUs) exposed to battery transients and load dump. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between converter output and ground to limit overshoot during switching or fault events. Use Value: Limits clamped voltage to 15.9V, ensuring downstream microcontrollers and CAN transceivers remain within absolute maximum ratings during ISO 7637-2 Pulse 2b events. | Use Scenario: Safeguarding primary-side input of offline flyback converters in factory automation power supplies subjected to AC line surges. IC Role / Device Role / Timing Role: Standoff-rated TVS on rectified DC bus to absorb energy from differential-mode surges before they reach the PWM controller. Use Value: 400W peak pulse power rating handles 1kV/0.5J surges per IEC 61000-4-5, preventing latch-up or gate oxide damage in MOSFET drivers. |
| LED Driver Power Inputs | On-Board Charger (OBC) Auxiliary Rails |
Use Scenario: Securing constant-current LED driver inputs in streetlight systems where lightning-induced surges propagate through long cable runs. IC Role / Device Role / Timing Role: Primary overvoltage guard on 24V/48V supply line upstream of buck controller IC and current-sense amplifier. Use Value: Sub-1ps response ensures clamping initiates before 10ns-fast transients exceed the 16V tolerance of op-amps and reference ICs in feedback loop. | Use Scenario: Protecting 12V auxiliary power rail in electric vehicle on-board chargers that interface with 12V battery and body control modules. IC Role / Device Role / Timing Role: Bidirectional-capable variant not required; unidirectional SMAJ8.5H used with cathode grounded to clamp negative-going spikes from relay coil back-EMF. Use Value: 1μA leakage at 8.5V prevents measurable drain on standby battery, supporting >1-year parking mode without recharge. |
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 SMAJ8.5A | Same VWM (8.5V), but tighter VBR range (9.44–10.40V); lower VC (14.4V @ 10A); AEC-Q101 qualified. | Marginally better clamping performance; identical footprint and mounting. | Select SMAJ8.5A if system-level testing shows marginal margin at 15.9V clamping; verify layout compatibility with Littelfuse's thermal pad recommendations. |
| Vishay SMAJ8.5 | VWM = 8.5V, VBR = 9.44–11.50V (same as SMAJ8.5H), but non-AEC-Q101; VC = 15.9V; RoHS/halogen-free compliant. | Not qualified for automotive; suitable for industrial/commercial designs where AEC-Q101 is not mandated. | Choose Vishay SMAJ8.5 for cost-sensitive non-automotive applications requiring identical electrical specs without qualification overhead. |
Compared with SMAJ8.5A and Vishay SMAJ8.5, the Taiwan Semiconductor SMAJ8.5H provides AEC-Q101 validation and identical clamping performance to the Vishay part, while offering broader VBR tolerance than SMAJ8.5A - advantageous in high-volume manufacturing where parametric spread must be accommodated without derating.
Availability
SMAJ8.5H is available at Aetrix Electronics and suitable for automotive DC/DC converters, industrial SMPS input protection, and LED driver power inputs requiring stable component supply across extended production lifecycles.
Supply support for SMAJ8.5H 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 certification capability.
The SMAJ series is engineered for high-reliability transient suppression in automotive and industrial power systems, emphasizing fast response, stable clamping, and robust packaging for automated SMT assembly.
FAQ
What is the maximum clamping voltage of the SMAJ8.5H under a 10A 10/1000μs surge?
The SMAJ8.5H has a maximum clamping voltage (VC) of 15.9 V when subjected to a 10A peak pulse current with a 10/1000μs waveform. This value is measured per standard test conditions (TA = 25°C) and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ8.5H maintains this clamping performance consistently across its qualified operating temperature range.
Is the SMAJ8.5H suitable for bidirectional transient protection?
No, the SMAJ8.5H is a unidirectional TVS diode intended for protection against positive transients only. For bidirectional applications, Taiwan Semiconductor specifies variants with CH or CAH suffixes (e.g., SMAJ8.5CH). Using SMAJ8.5H in a bidirectional configuration would leave the circuit vulnerable to negative-going surges exceeding its forward voltage rating (VF = 3.5 V).
Does the SMAJ8.5H meet automotive qualification standards?
Yes, the SMAJ8.5H is AEC-Q101 qualified and meets ISO 7637-2 Pulse 1, 2a, 2b, 3a, and 3b transient immunity requirements. It also complies with JESD201 Class 2 whisker resistance and J-STD-020 moisture sensitivity level 1 - confirming suitability for automotive underhood and powertrain applications without pre-bake or special handling.
What is the reverse leakage current specification for the SMAJ8.5H at its working stand-off voltage?
The SMAJ8.5H exhibits a maximum reverse leakage current (IR) of 1 μA when biased at its 8.5 V working stand-off voltage (VWM). This ultra-low leakage ensures minimal power loss in always-on systems and avoids interference with precision analog monitoring circuits, such as those used in battery management or sensor front-ends.
What package type does the SMAJ8.5H use, and is it compatible with standard SMA footprints?
The SMAJ8.5H uses the DO-214AC (SMA) surface-mount package, with standardized dimensions and cathode band marking. It is fully compatible with industry-standard SMA footprints and reflow profiles, supporting automated placement and meeting J-STD-002 solderability requirements. The matte tin-plated leads ensure reliable interconnect integrity in high-volume manufacturing.
SMAJ8.5H 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:
- 15.9V
- Current - Peak Pulse (10/1000µs):
- 25.2A
- 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)
SMAJ8.5H FAQ
1.How can I place an order for SMAJ8.5H through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ8.5H 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 SMAJ8.5H reliable?
The price and inventory of SMAJ8.5H are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ8.5H is usually 5 days.
3.What payment methods are accepted for SMAJ8.5H?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ8.5H transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ8.5H?
SMAJ8.5H orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ8.5H 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 SMAJ8.5H?
For technical support, including SMAJ8.5H datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ8.5H requirements.
6.How does Aetrix verify that SMAJ8.5H is sourced from the original manufacturer or authorized distributors?
All SMAJ8.5H 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 SMAJ8.5H meets industry standards.
7.What is the process for return or replacement of SMAJ8.5H?
All SMAJ8.5H units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ8.5H, 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 SMAJ8.5H part is unused and in its original packaging.
Return procedure for SMAJ8.5H:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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