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Vishay General Semiconductor - Diodes Division 3KASMC18HE3/9AT
- Part No.:
- 3KASMC18HE3/9AT
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AB, SMC
- Datasheet:
-
3KASMC18HE3/9AT.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AB
- Quantity:
- Payment:
- Shipping:
Inventory:6,537
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Product details
Overview
3KASMC18HE3/9AT from Vishay General Semiconductor is a unidirectional surface-mount transient voltage suppressor (TVS) diode in DO-214AB (SMC) package, rated for 18 V stand-off voltage, 20.0–22.1 V breakdown at 1 mA, 3000 W peak pulse power (10/1000 µs), 103 A peak surge current, and 29.2 V clamping voltage. It delivers high-reliability protection for automotive power rails and sensor interfaces.
For engineers reviewing the 3KASMC18HE3/9AT datasheet, 3KASMC18HE3/9AT pinout, 3KASMC18HE3/9AT application, or 3KASMC18HE3/9AT equivalent, this page provides verified electrical parameters, AEC-Q101 qualification status, thermal resistance (RθJA = 77.5 °C/W), junction temperature limit (TJ = 185 °C), and DO-214AB mechanical layout details required for PCB design and automotive-grade ESD/surge validation.
Technical Context
This TVS diode uses passivated anisotropic rectifier technology optimized for high-temperature stability and low incremental surge resistance. Its unidirectional polarity enables forward-biased clamping during positive transients on DC supply lines, with fast response time and excellent clamping ratio (VC/VBR ≈ 1.32).
Designed for AEC-Q101 qualification, it supports operation from –65 °C to +185 °C junction temperature and meets MSL Level 1 per J-STD-020 with 260 °C lead-free reflow peak. The device is rated for 200 A non-repetitive forward surge (8.3 ms half-sine) and exhibits 3.5 V maximum forward voltage at 100 A.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse operating voltage before leakage exceeds 1 μA; defines safe DC rail protection threshold. |
| VBR (min/max) | 20.0 V / 22.1 V at IT = 1 mA - Confirmed breakdown range ensures predictable turn-on during overvoltage events. |
| PPPM | 3000 W (10/1000 µs) - Sustains high-energy transients common in automotive load-dump and inductive switching. |
| IPPM | 103 A - Peak surge current capability directly supports ISO 7637-2 Pulse 5a compliance margin. |
| VC | 29.2 V at IPPM - Clamping voltage limits downstream IC stress; clamping ratio of 1.32 indicates efficient suppression. |
| TJ max | +185 °C - Enables under-hood deployment without derating in engine control units and body electronics. |
| RθJA | 77.5 °C/W - Thermal resistance informs board-level heatsinking requirements for sustained power dissipation. |
Pinout & Package
Package: DO-214AB (SMC), surface-mount, matte tin-plated leads, RoHS-compliant, AEC-Q101 qualified. Cathode indicated by color band.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward conduction terminal | Connected to system ground or lower-potential node; conducts during positive transients when cathode is at higher potential. |
| Cathode | Reverse-biased clamping terminal | Connected to protected line (e.g., 12 V rail); initiates avalanche breakdown above VBR to shunt surge energy. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive electronic modules requiring zero-failure reliability across temperature and lifetime stress tests. |
| Junction passivation | Enhanced moisture and contamination resistance improves long-term stability in humid under-hood environments. |
| MSL Level 1 rating | Enables standard SMT assembly without baking; compatible with 260 °C lead-free reflow profiles. |
| Low Rsurge | Minimizes voltage overshoot during fast-rising transients (e.g., ISO 10605 ESD), improving protection fidelity. |
| 185 °C TJ max | Eliminates thermal derating in high-ambient applications such as powertrain and ADAS ECUs. |
Applications
| Automotive Power Rail Protection | Engine Control Unit (ECU) Input Protection |
|---|---|
Use Scenario: Suppresses load-dump transients (ISO 7637-2 Pulse 5a) on 12 V battery-fed circuits in vehicles. IC Role / Device Role / Timing Role: Unidirectional TVS diode placed between battery rail and input filter capacitor. Use Value: Clamps surge to ≤29.2 V within nanoseconds, protecting downstream DC/DC converters and microcontrollers rated for 30 V absolute max. |
Use Scenario: Shields ECU microcontroller power inputs from alternator-induced spikes and relay-switching noise. IC Role / Device Role / Timing Role: Primary overvoltage clamp on main 5 V or 3.3 V regulator input. Use Value: Withstands 200 A 8.3 ms surge and maintains <1 μA leakage at 18 V, ensuring low quiescent current in always-on domains. |
| Automotive Sensor Interface Protection | Industrial CAN Bus Node Protection |
Use Scenario: Protects analog sensor signal lines (e.g., oxygen, pressure) from ESD and cable discharge events. IC Role / Device Role / Timing Role: Low-capacitance unidirectional TVS placed at connector entry point. Use Value: Delivers 29.2 V clamping with sub-100 pF junction capacitance (typ.) at zero bias, preserving signal integrity up to 1 MHz. |
Use Scenario: Guards CANH/CANL transceiver pins against ISO 11898-2 bus faults and coupling transients. IC Role / Device Role / Timing Role: Secondary protection stage after common-mode choke, referenced to local ground. Use Value: 3000 W peak power rating absorbs multiple repetitive surges without degradation, supporting industrial CAN networks with frequent hot-plug cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A | Same DO-214AC (SMA) package; lower PPPM = 400 W; VC = 29.2 V at 13.9 A; RθJA = 110 °C/W. | Not AEC-Q101 qualified; limited to consumer/industrial use; insufficient for automotive load-dump. | Select only for cost-sensitive, non-automotive designs where 400 W surge margin suffices. |
| SMCJ18A | Same DO-214AB (SMC) package; identical PPPM = 3000 W and VC = 29.2 V; but rated for TJ = 175 °C (not 185 °C) and not AEC-Q101 certified. | Lacks automotive qualification; thermal margin reduced by 10 °C - may require derating in high-ambient ECU locations. | Acceptable for industrial controls or non-safety-critical automotive subsystems where full AEC-Q101 is not mandated. |
Compared with SMAJ18A and SMCJ18A, the 3KASMC18HE3/9AT provides superior junction temperature capability (+185 °C), formal AEC-Q101 certification, and guaranteed MSL Level 1 process compatibility - making it the only option qualified for front-end power protection in ASIL-B compliant vehicle systems.
Availability
3KASMC18HE3/9AT is available at Aetrix Electronics and suitable for automotive power rail protection, engine control unit (ECU) input conditioning, and sensor interface surge suppression requiring stable component supply, long-term lifecycle assurance, and AEC-Q101 traceability.
Supply support for 3KASMC18HE3/9AT 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
Vishay General Semiconductor is a global leader in discrete semiconductors, specializing in high-reliability diodes, MOSFETs, and optoelectronics for automotive, industrial, and computing markets.
The 3KASMC series is part of Vishay's PAR® (Protected Anisotropic Rectifier) TVS platform, engineered specifically for under-hood automotive applications demanding extended temperature operation, AEC-Q101 compliance, and robust surge immunity.
FAQ
What is the clamping voltage of the 3KASMC18HE3/9AT at its rated peak pulse current?
The 3KASMC18HE3/9AT has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current (IPPM) of 103 A using a 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 standards and ensures downstream components see no more than 29.2 V during worst-case surge events. The 3KASMC18HE3/9AT achieves this with low incremental surge resistance, minimizing overshoot beyond VC.
Is the 3KASMC18HE3/9AT qualified for automotive applications?
Yes, the 3KASMC18HE3/9AT is AEC-Q101 qualified and rated for operation from –65 °C to +185 °C junction temperature, making it suitable for under-hood automotive modules including engine control units, body control modules, and ADAS sensors. Its DO-214AB package meets MSL Level 1 and passes JESD201 Class 2 whisker testing. The 3KASMC18HE3/9AT is explicitly listed in Vishay's AEC-Q101 qualified product matrix.
What is the marking code for the 3KASMC18HE3/9AT on the device body?
The 3KASMC18HE3/9AT is marked with the code "3BT" on its package body, as confirmed in the Vishay datasheet (Document Number: 89962, Table on page 2). This two-character marking identifies the 18 V variant within the 3KASMCxxA family and is laser-etched on the cathode-band end of the DO-214AB (SMC) case. The "3BT" marking is consistent across all packaging variants, including the 3KASMC18HE3/9AT reel format.
Does the 3KASMC18HE3/9AT have bidirectional polarity?
No, the 3KASMC18HE3/9AT is unidirectional only, as stated in the Vishay datasheet's FEATURES section. It functions as a single-junction avalanche diode with cathode band indicating the high-side terminal; it clamps positive transients on the cathode side relative to anode (ground). Bidirectional variants (e.g., 3KASMC18CA) are separate part numbers and are not interchangeable with the 3KASMC18HE3/9AT.
What is the thermal resistance from junction to ambient for the 3KASMC18HE3/9AT?
The typical thermal resistance from junction to ambient (RθJA) for the 3KASMC18HE3/9AT is 77.5 °C/W, measured on the minimum recommended pad layout per the Vishay datasheet (page 3, THERMAL CHARACTERISTICS table). This value assumes standard FR-4 PCB with specified copper area and is critical for calculating junction temperature rise under continuous power dissipation conditions. The 3KASMC18HE3/9AT also has RθJL = 18.3 °C/W for junction-to-leads conduction.
3KASMC18HE3/9AT Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AB, SMC
- Series:
- PAR®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 32.2V
- Current - Peak Pulse (10/1000µs):
- 93.2A
- Power - Peak Pulse:
- 3000W (3kW)
- Power Line Protection:
- No
- Applications:
- -
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -65°C ~ 185°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AB (SMCJ)
3KASMC18HE3/9AT FAQ
1.How can I place an order for 3KASMC18HE3/9AT through Aetrix?
Please submit a Request for Quotation (RFQ) for 3KASMC18HE3/9AT 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 3KASMC18HE3/9AT reliable?
The price and inventory of 3KASMC18HE3/9AT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 3KASMC18HE3/9AT is usually 5 days.
3.What payment methods are accepted for 3KASMC18HE3/9AT?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 3KASMC18HE3/9AT transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 3KASMC18HE3/9AT?
3KASMC18HE3/9AT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 3KASMC18HE3/9AT 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 3KASMC18HE3/9AT?
For technical support, including 3KASMC18HE3/9AT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 3KASMC18HE3/9AT requirements.
6.How does Aetrix verify that 3KASMC18HE3/9AT is sourced from the original manufacturer or authorized distributors?
All 3KASMC18HE3/9AT 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 3KASMC18HE3/9AT meets industry standards.
7.What is the process for return or replacement of 3KASMC18HE3/9AT?
All 3KASMC18HE3/9AT units undergo pre-shipment inspection (PSI). If there is an issue with 3KASMC18HE3/9AT, 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 3KASMC18HE3/9AT part is unused and in its original packaging.
Return procedure for 3KASMC18HE3/9AT:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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