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Taiwan Semiconductor Corporation SMAJ8.5CH
- Part No.:
- SMAJ8.5CH
- Manufacturer:
- Taiwan Semiconductor Corporation
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ8.5CH.pdf
- Description:
- 400W, 10.5V, BIDIRECTIONAL, TVS
- Quantity:
- Payment:
- Shipping:
Inventory:8,192
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Product details
Overview
SMAJ8.5CH from Taiwan Semiconductor is a unidirectional 400W transient voltage suppressor (TVS) diode in DO-214AC (SMA) package, designed for automotive-grade overvoltage protection with 8.5V working stand-off voltage, 9.44–11.50V breakdown range at 1mA test current, and 15.9V clamping voltage at 10A peak impulse current. It protects DC/DC converters and SMPS inputs against ISO 7637-2 Pulse 1/2a/2b/3a/3b transients.
For engineers reviewing the SMAJ8.5CH datasheet, SMAJ8.5CH pinout, SMAJ8.5CH application, or SMAJ8.5CH equivalent, this part delivers AEC-Q101-qualified surge immunity, sub-1ps response time, <1μA leakage above 10V, UL 94V-0 molding, and JESD201 Class 2 whisker resistance - critical for automotive power rail hardening and industrial adapter ESD resilience.
Technical Context
This unidirectional TVS operates as a voltage-clamped shunt protector: when reverse voltage exceeds VBR (9.44–11.50V), it avalanches to clamp transient energy within VC = 15.9V at IPPM = 10A under 10/1000μs waveform. Its glass-passivated junction ensures stable breakdown and low leakage (<1μA @ 8.5V).
Designed for automotive environments, SMAJ8.5CH meets ISO 7637-2 Pulse 1 (inductive load dump suppression), Pulse 2a/2b (battery disconnection & coupling), and Pulse 3a/3b (capacitive switching noise), with operating junction temperature from –55°C to +150°C and moisture sensitivity level 1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 8.5 V - Maximum continuous reverse operating voltage before conduction begins; sets minimum system rail margin for reliable standby operation. |
| VBR min/max | 9.44 V / 11.50 V @ 1 mA - Confirmed avalanche onset range; ensures consistent turn-on across production lots and temperature. |
| VC @ IPPM | 15.9 V @ 10 A - Clamped voltage during 10/1000μs surge; defines maximum stress imposed on downstream ICs during worst-case transients. |
| PPPM | 400 W - Peak pulse power rating per 10/1000μs waveform; supports robust protection of 12V automotive subsystems without derating below 78V. |
| IR @ VWM | <1 μA - Reverse leakage at 8.5V; negligible power loss and thermal impact in always-on circuits like CAN bus power rails. |
| TJ max | +150 °C - Maximum junction temperature; enables placement near hot components (e.g., MOSFETs, inductors) in compact power modules. |
Pinout & Package
DO-214AC (SMA) surface-mount package: molded epoxy case with matte tin-plated leads, polarity indicated by cathode band, weight ≈ 0.060 g, UL 94V-0 rated, JESD201 Class 2 whisker compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to system ground or lower-potential node; completes shunt path during reverse transient events. |
| Cathode | Protected line connection | Connected to protected rail (e.g., 12V input); avalanche conduction occurs between cathode and anode when VAK ≥ VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive underhood use including temperature cycling, humidity bias, and mechanical shock - no requalification needed for Tier 1 designs. |
| Glass passivated junction | Stable VBR tolerance and low IR drift over lifetime; eliminates risk of parametric shift due to surface contamination or humidity ingress. |
| Sub-1 ps response time | Clamps transients before propagation into sensitive analog or digital circuitry; essential for protecting high-speed CAN FD or LIN transceivers. |
| ISO 7637-2 compliance | Passes all five standardized automotive transient pulses (Pulse 1, 2a, 2b, 3a, 3b) without degradation - simplifies EMC validation. |
| Moisture sensitivity level 1 | No floor life limitation or bake requirement before reflow; supports standard SMT assembly without special handling. |
Applications
| Automotive Body Control Module (BCM) | Industrial AC-DC Adapter |
|---|---|
Use Scenario: Protects 12V supply input of BCM microcontroller and CAN transceiver from load dump and battery disconnect spikes. IC Role / Device Role / Timing Role: Unidirectional shunt TVS placed directly at connector entry point, clamping transients before they reach LDOs and communication ICs. Use Value: Limits peak rail voltage to ≤15.9V during ISO 7637-2 Pulse 1 (100V/100ms), preventing latch-up or permanent damage to 16V-rated regulators. |
Use Scenario: Shields primary-side controller IC and optocoupler feedback path in offline flyback adapters against surges from mains switching. IC Role / Device Role / Timing Role: Mounted across bulk capacitor input, absorbing 400W 10/1000μs surges induced by relay contact bounce or lightning-induced coupling. Use Value: Maintains VWM = 8.5V margin below typical 12V adapter output, enabling safe operation while rejecting >100V transients without crowbar action. |
| On-board DC/DC Converter | LED Driver Power Input |
Use Scenario: Secures 24V-to-5V buck converter input in commercial vehicle lighting control units exposed to alternator ripple and inductive kick. IC Role / Device Role / Timing Role: Placed upstream of input filter inductor, acting as first-line defense against fast-rising transients that bypass LC filtering. Use Value: Sub-1ps response ensures clamping initiates before 10ns edge rates propagate into PWM controller, preserving regulation stability. |
Use Scenario: Guards constant-current LED driver IC against ESD and switching noise from nearby relays or solenoids in architectural lighting systems. IC Role / Device Role / Timing Role: Connected between LED string positive rail and chassis ground, suppressing common-mode transients coupled via long cable runs. Use Value: 15.9V clamping voltage stays below absolute maximum ratings of most LED driver ICs (typically 20–28V), eliminating need for series resistors or additional TVS stages. |
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 SMAJ8.5AHE3/5A | Same DO-214AC package, bidirectional configuration (CH suffix denotes unidirectional; AH suffix indicates tighter VBR tolerance: 9.44–10.40V vs. SMAJ8.5CH's 9.44–11.50V). | Supports symmetric transient suppression in AC-coupled or floating-rail systems; not suitable where strict unidirectional blocking is required. | Select SMAJ8.5CH for cost-sensitive unidirectional 12V rail protection; choose SMAJ8.5AH variant only if tighter VBR distribution is needed for margin-critical designs. |
| Vishay SMAJ8.5A-M3/84A | Identical electrical specs (VWM = 8.5V, VBR = 9.44–10.40V, VC = 14.4V @ 10A), AEC-Q101 qualified, same DO-214AC package but with matte tin finish per J-STD-002B. | No functional difference in surge handling; differs only in lead finish specification and traceability documentation. | Interchangeable in layout and performance; prefer SMAJ8.5CH when sourcing from Taiwan Semiconductor's authorized channel for BOM continuity assurance. |
Compared with SMAJ8.5AHE3/5A and SMAJ8.5A-M3/84A, SMAJ8.5CH offers identical clamping performance and automotive qualification but with broader VBR tolerance (±12.5% vs. ±5.5%), making it more tolerant of process variation while maintaining full ISO 7637-2 compliance at lower cost.
Availability
SMAJ8.5CH is available at Aetrix Electronics and suitable for automotive body electronics, industrial power adapters, and on-board DC/DC converters requiring stable component supply with AEC-Q101 validation and full traceability.
Supply support for SMAJ8.5CH 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 Taiwanese semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs since 1979.
The SMAJ series was developed specifically for AEC-Q101-compliant automotive transient suppression, targeting 12V/24V power rail hardening in ECUs, lighting modules, and infotainment systems with high reliability and zero-bake assembly compatibility.
FAQ
What does the "CH" suffix indicate in SMAJ8.5CH?
The "CH" suffix in SMAJ8.5CH designates a unidirectional TVS diode in DO-214AC (SMA) package with 8.5V working stand-off voltage. The "C" confirms unidirectional polarity (cathode-marked), and "H" identifies the SMAJ family's 400W 10/1000μs pulse rating. SMAJ8.5CH is not interchangeable with bidirectional variants like SMAJ8.5CAH.
Is SMAJ8.5CH suitable for ISO 7637-2 Pulse 1 testing?
Yes, SMAJ8.5CH is explicitly rated to meet ISO 7637-2 Pulse 1 (inductive load dump) requirements. With a 15.9V clamping voltage at 10A and 400W peak pulse capability, it limits transient voltage on 12V systems to well below the 25V threshold specified for Pulse 1 immunity testing, ensuring robust protection without secondary crowbar circuits.
What is the maximum junction temperature rating for SMAJ8.5CH?
The maximum junction temperature (TJMAX) for SMAJ8.5CH is +150°C, validated per AEC-Q101 stress testing. This allows direct placement adjacent to heat-generating components such as power inductors or MOSFETs in automotive DC/DC modules, provided PCB copper area and ambient conditions maintain TJ ≤ 150°C under worst-case surge duty cycles.
Does SMAJ8.5CH require moisture baking before reflow soldering?
No, SMAJ8.5CH has a moisture sensitivity level (MSL) of 1 per J-STD-020, meaning it is not moisture-sensitive and requires no floor life limitation or pre-reflow baking. It can be stored indefinitely at ambient conditions and processed using standard lead-free reflow profiles without popcorn or delamination risk.
How does the clamping voltage of SMAJ8.5CH compare to its breakdown voltage?
SMAJ8.5CH has a breakdown voltage (VBR) range of 9.44–11.50V at 1mA and a maximum clamping voltage (VC) of 15.9V at 10A IPPM. This ~40% overvoltage margin ensures reliable conduction during fast transients while limiting downstream stress - critical for protecting 16V-rated LDOs and microcontrollers in automotive applications.
SMAJ8.5CH 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:
- -
- Bidirectional Channels:
- 1
- 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)
SMAJ8.5CH FAQ
1.How can I place an order for SMAJ8.5CH through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ8.5CH 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 SMAJ8.5CH reliable?
The price and inventory of SMAJ8.5CH are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ8.5CH is usually 5 days.
3.What payment methods are accepted for SMAJ8.5CH?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ8.5CH transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ8.5CH?
SMAJ8.5CH orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ8.5CH 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 SMAJ8.5CH?
For technical support, including SMAJ8.5CH datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ8.5CH requirements.
6.How does Aetrix verify that SMAJ8.5CH is sourced from the original manufacturer or authorized distributors?
All SMAJ8.5CH 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 SMAJ8.5CH meets industry standards.
7.What is the process for return or replacement of SMAJ8.5CH?
All SMAJ8.5CH units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ8.5CH, 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 SMAJ8.5CH part is unused and in its original packaging.
Return procedure for SMAJ8.5CH:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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