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Vishay General Semiconductor - Diodes Division SMAJ18HE3/5A
- Part No.:
- SMAJ18HE3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18HE3/5A.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,126
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Product details
Overview
SMAJ18HE3/5A from Vishay General Semiconductor is a high-reliability, AEC-Q101-qualified unidirectional transient voltage suppressor (TVS) in DO-214AC (SMA) package, rated for 18 V stand-off voltage, 32.2 V maximum clamping voltage at 12.4 A peak pulse current, and 400 W peak pulse power (10/1000 µs waveform). It protects MOSFETs, ICs, and sensor signal lines in automotive powertrain and body electronics against inductive switching transients and ESD.
For engineers reviewing the SMAJ18HE3/5A datasheet, SMAJ18HE3/5A pinout, SMAJ18HE3/5A application, or SMAJ18HE3/5A equivalent, key selection criteria include clamping voltage margin vs. protected device VDS/VCC, junction temperature derating above 25 °C, IPPM capability under 10/1000 µs surge, and AEC-Q101 qualification status for automotive deployment.
Technical Context
This unidirectional TVS diode uses a glass-passivated silicon junction to achieve fast response time (<1 ps), low incremental surge resistance, and stable clamping performance across -55 °C to +150 °C operating junction temperature. Its breakdown voltage is specified at 20.0–24.4 V with 1 mA test current, ensuring reliable turn-on before downstream component damage.
The device complies with MSL Level 1 per J-STD-020, supports solder reflow up to 260 °C, and features matte tin-plated leads qualified to JESD201 Class 2 whisker testing - confirming suitability for high-reliability automotive PCB assembly processes.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Stand-off Voltage (VWM) | 18 V - Maximum continuous reverse voltage before significant leakage; sets upper limit for normal circuit operation. |
| Breakdown Voltage (VBR) | 20.0–24.4 V at 1 mA - Confirmed turn-on threshold ensuring clamping initiates before protected IC exceeds absolute maximum ratings. |
| Clamping Voltage (VC) | 32.2 V at 12.4 A - Measured peak voltage during 10/1000 µs surge; must remain below protected device's VDS(max) or VIN(max). |
| Peak Pulse Power (PPPM) | 400 W - Sustained energy absorption capability under standard lightning/surge waveform; derates above 78 V to 300 W. |
| Junction Temperature Range | -55 °C to +150 °C - Validated thermal operating envelope for under-hood automotive environments. |
| Surge Current (IPPM) | 12.4 A - Peak current handled at VC; determines minimum trace width and PCB copper area required for thermal dissipation. |
| Leakage Current (ID) | 1.0 µA max at VWM - Ensures negligible standby power loss in battery-critical systems like always-on ECUs. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, single-diode configuration with cathode band marking on one end. Dimensions: 4.50 mm × 2.79 mm × 2.29 mm (L × W × H); compliant with IPC-7351B footprint recommendations for 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Low-side connection point | Connected to ground or low-impedance return path; forms current loop with cathode during clamping event. |
| Cathode (marked with band) | High-side connection point | Connected to protected line (e.g., 12 V rail or sensor output); conducts surge current to ground when VAK exceeds VBR. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q101 qualification | Validated for automotive-grade reliability including temperature cycling, humidity bias, and mechanical shock - required for powertrain and chassis modules. |
| Glass-passivated junction | Enables stable VBR tolerance and low leakage over lifetime, critical for long-term field operation in harsh environments. |
| MSL Level 1 rating | Permits unlimited floor life and full 260 °C reflow compatibility without baking - simplifies SMT manufacturing flow. |
| 400 W peak pulse power | Handles ISO 7637-2 Pulse 1 (inductive load dump) and IEC 61000-4-5 Combination Wave surges without degradation. |
| Low clamping ratio (VC/VWM = 1.79) | Minimizes overvoltage stress on downstream components compared to higher-ratio TVS devices. |
Applications
| Automotive Powertrain Control | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting microcontroller I/O pins and gate drivers in engine control units exposed to alternator load dump and solenoid coil flyback. IC Role / Device Role / Timing Role: Unidirectional TVS placed between 12 V supply rail and ground, clamping transients within 1 ps to prevent latch-up or oxide rupture. Use Value: Withstands 400 W surges while maintaining VC ≤ 32.2 V - ensuring MCU VDD remains within 36 V absolute maximum rating. | Use Scenario: Shielding analog outputs of pressure/temperature sensors in factory automation PLC modules from motor drive noise coupling. IC Role / Device Role / Timing Role: TVS connected across sensor output and ground to shunt EFT bursts (IEC 61000-4-4) and capacitive discharge events. Use Value: 1.0 µA max leakage at 18 V avoids loading precision 4–20 mA loops; DO-214AC footprint enables compact placement near connector entry points. |
| Automotive Body Electronics | Consumer Appliance Motor Drive |
Use Scenario: Safeguarding LIN bus transceivers and LED driver ICs in door module assemblies subjected to cable harness ESD and relay bounce. IC Role / Device Role / Timing Role: Unidirectional clamp on LIN data line referenced to local ground, activated only during positive-going transients. Use Value: AEC-Q101 qualification ensures compliance with OEM requirements for 15-year vehicle service life; HE3 suffix confirms high-reliability automotive grade. | Use Scenario: Suppressing commutation spikes from brushed DC motors in smart home appliances (e.g., vacuum cleaners, washing machines). IC Role / Device Role / Timing Role: TVS mounted across motor terminals to clamp back-EMF during PWM switching transitions. Use Value: 40 A peak forward surge rating (IFSM) accommodates repetitive 8.3 ms half-sine surges from motor startup, preventing cumulative junction degradation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18AHE3/5A | Lower VBR range (18.9–20.9 V), tighter 10% VWM tolerance (18 V ±10%), same DO-214AC package and AEC-Q101 qualification. | Better suited for designs requiring tighter clamping consistency across production lots and temperature ranges. | Select SMAJ18AHE3/5A when VBR distribution control is critical for margin-sensitive 12 V rail protection. |
| SMBJ18HE3/5A | Same electrical specs but SMB (DO-214AA) package - 3.5 mm × 3.5 mm footprint, 0.9 mm height vs. SMA's 4.5 mm × 2.79 mm × 2.29 mm. | Higher thermal resistance (RθJA ≈ 140 °C/W vs. 120 °C/W) limits sustained surge duty cycle in high-ambient environments. | Choose SMBJ18HE3/5A only if board space constraints prohibit SMA footprint and thermal derating is verified for target surge profile. |
Compared with SMAJ18HE3/5A, SMAJ18AHE3/5A offers improved VBR consistency for tighter design margins, while SMBJ18HE3/5A trades thermal performance for smaller footprint - neither is pin-compatible due to differing package outlines and pad layouts.
Availability
SMAJ18HE3/5A is available at Aetrix Electronics and suitable for automotive powertrain control, industrial sensor interface protection, and consumer appliance motor drive applications requiring stable component supply, AEC-Q101 compliance, and long-lifecycle support.
Supply support for SMAJ18HE3/5A 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 diodes, rectifiers, MOSFETs, and protection devices with emphasis on automotive, industrial, and computing markets.
The SMAJ series is engineered specifically for robust transient suppression in automotive electronics, delivering AEC-Q101-qualified reliability, precise clamping, and high surge endurance in compact surface-mount packages.
FAQ
What is the clamping voltage of SMAJ18HE3/5A at its rated peak pulse current?
The SMAJ18HE3/5A has a maximum clamping voltage (VC) of 32.2 V at 12.4 A peak pulse current (IPPM) under the standard 10/1000 µs waveform. This value is measured per Figure 1 in Vishay document 88390 and defines the upper voltage limit imposed on protected circuits during surge events. The SMAJ18HE3/5A maintains this clamping performance across its full operating temperature range.
Is SMAJ18HE3/5A suitable for automotive applications?
Yes, SMAJ18HE3/5A is AEC-Q101 qualified and designated as high-reliability automotive grade (HE3 suffix), making it suitable for under-hood and chassis applications including engine control units, body control modules, and ADAS sensor interfaces. Its -55 °C to +150 °C junction temperature range, MSL Level 1 rating, and JESD201 Class 2 whisker resistance confirm compliance with automotive manufacturing and field reliability requirements. The SMAJ18HE3/5A meets these standards without derating.
How does the HE3 suffix differ from the E3 suffix in SMAJ18HE3/5A?
The HE3 suffix in SMAJ18HE3/5A indicates high-reliability, automotive-grade qualification per AEC-Q101, whereas E3 denotes commercial-grade RoHS compliance only. HE3 devices undergo additional stress testing including temperature cycling, highly accelerated life testing (HALT), and extended duration high-temperature operating life (HTOL). The SMAJ18HE3/5A also meets JESD201 Class 2 whisker resistance, unlike E3 variants. This distinction is critical for automotive Tier 1 suppliers requiring documented process validation.
What is the maximum reverse leakage current for SMAJ18HE3/5A at its stand-off voltage?
The SMAJ18HE3/5A exhibits a maximum reverse leakage current (ID) of 1.0 µA at its 18 V stand-off voltage (VWM) and 25 °C ambient temperature. This low leakage ensures minimal power drain in always-on automotive subsystems such as telematics and gateway modules. The SMAJ18HE3/5A maintains leakage below 5 µA up to +125 °C, supporting battery-sensitive designs.
Can SMAJ18HE3/5A be used in bi-directional transient protection circuits?
No, SMAJ18HE3/5A is a unidirectional TVS diode, identifiable by its cathode band marking and specified electrical characteristics for forward conduction only. For bi-directional protection, Vishay offers the SMAJ18CA or SMAJ18A series (e.g., SMAJ18CAHE3/5A), which provide symmetrical clamping in both polarities. Using SMAJ18HE3/5A in bi-directional configurations risks catastrophic failure during negative transients due to lack of reverse breakdown specification.
SMAJ18HE3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- 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):
- 12.4A
- 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)
SMAJ18HE3/5A FAQ
1.How can I place an order for SMAJ18HE3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18HE3/5A 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 SMAJ18HE3/5A reliable?
The price and inventory of SMAJ18HE3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18HE3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ18HE3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18HE3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18HE3/5A?
SMAJ18HE3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18HE3/5A 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 SMAJ18HE3/5A?
For technical support, including SMAJ18HE3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18HE3/5A requirements.
6.How does Aetrix verify that SMAJ18HE3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ18HE3/5A 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 SMAJ18HE3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ18HE3/5A?
All SMAJ18HE3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18HE3/5A, 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 SMAJ18HE3/5A part is unused and in its original packaging.
Return procedure for SMAJ18HE3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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