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Vishay General Semiconductor - Diodes Division SMAJ18CAHE3_A/I
- Part No.:
- SMAJ18CAHE3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18CAHE3_A/I.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,290
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Product details
Overview
SMAJ18CAHE3_A/I from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for robust overvoltage protection of sensitive electronics. It features a 18 V standoff voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 400 W peak pulse power (10/1000 μs), and clamps transients to ≤29.2 V at 13.7 A peak surge current - deployed on signal lines and power rails in automotive ECUs and industrial sensor interfaces.
For engineers reviewing the SMAJ18CAHE3_A/I datasheet, SMAJ18CAHE3_A/I pinout, SMAJ18CAHE3_A/I application, or SMAJ18CAHE3_A/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, 150 °C junction temperature rating, low incremental surge resistance, and compatibility with automated SMT placement on 0.2" × 0.2" copper pads.
Technical Context
This device operates as a voltage-clamping protector: under normal conditions it presents high impedance (>1 μA leakage at 18 V), but switches to low-impedance conduction within picoseconds when reverse voltage exceeds VBR, diverting surge energy away from downstream ICs. Its glass-passivated junction ensures stable breakdown characteristics and long-term reliability under repetitive transients.
The SMAJ18CAHE3_A/I is rated for 400 W peak pulse power (10/1000 μs waveform) up to 78 V, derating to 300 W above that threshold; thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), enabling operation from –55 °C to +150 °C without external heatsinking in typical PCB layouts.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 18 V - maximum continuous reverse operating voltage before significant leakage begins |
| VBR (Breakdown Voltage) | 20.0–22.1 V at 1 mA - precise voltage threshold triggering clamping action |
| VC (Clamping Voltage) | ≤29.2 V at 13.7 A IPPM - limits downstream voltage stress during surge events |
| PPPM (Peak Pulse Power) | 400 W (10/1000 μs) - energy-handling capacity for common lightning/inductive-switching transients |
| IPPM (Peak Pulse Current) | 13.7 A - maximum transient current safely diverted without degradation |
| TJmax | +150 °C - enables use in under-hood automotive and high-temperature industrial environments |
| AEC-Q101 Qualified | Yes - validated for automotive-grade reliability per stress test requirements |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking; matte tin-plated leads, MSL Level 1 (JEDEC J-STD-020), compatible with lead-free reflow profiles up to 260 °C peak.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal during positive transient | One side of symmetrical bidirectional structure; connects to protected line |
| Cathode | Current entry terminal during negative transient | Other side of symmetrical bidirectional structure; connects to protected line |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Protects AC-coupled or floating signal lines without polarity concerns |
| 400 W peak pulse power (10/1000 μs) | Handles IEC 61000-4-5 Level 4 surges (4 kV/2 Ω) on 12 V systems |
| AEC-Q101 qualified | Validated for automotive powertrain, body control, and ADAS modules |
| Low clamping ratio (VC/VBR ≈ 1.46) | Minimizes overvoltage margin required for downstream IC survival |
| MSL Level 1, 260 °C peak reflow | Enables single-pass assembly with standard lead-free SMT processes |
Applications
| Automotive Sensor Interface Protection | Industrial CAN Bus Line Protection |
|---|---|
|
Use Scenario: Protecting analog sensor outputs (e.g., pressure, temperature) in engine control units exposed to load dump and ISO 7637-2 pulses. IC Role / Device Role / Timing Role: Bidirectional TVS placed across differential sensor pair or between signal and ground to clamp ±200 V transients. Use Value: Prevents latch-up or gate oxide damage in precision op-amps and ADC front-ends by limiting voltage to ≤29.2 V during 13.7 A surges. |
Use Scenario: Safeguarding CANH/CANL lines in factory automation nodes subjected to ESD and inductive switching noise. IC Role / Device Role / Timing Role: TVS connected line-to-line and line-to-ground to absorb common-mode and differential transients per ISO 11898-2. Use Value: Maintains CAN signal integrity by clamping fast-rising edges (<1 ns response) while adding <1 pF capacitance at 0 V bias. |
| Consumer USB Port ESD Protection | Telecom Power Supply Input Clamping |
|
Use Scenario: Shielding USB 2.0 D+/D− lines in portable devices against human-body-model (HBM) ESD up to ±15 kV. IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS placed directly at connector to shunt ESD current before reaching PHY IC. Use Value: Enables compliance with IEC 61000-4-2 Level 4 without degrading 480 Mbps data eye due to sub-1 pF junction capacitance at VWM. |
Use Scenario: Suppressing 10/1000 μs surges on 24 V DC input rails of telecom base station power modules. IC Role / Device Role / Timing Role: Primary clamping device upstream of DC-DC converters to limit input voltage excursions during lightning-induced surges. Use Value: Absorbs 400 W transient energy without failure, reducing need for secondary crowbar circuits or oversized input capacitors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18CA-M3/5A | Halogen-free, RoHS-compliant, same electrical specs and AEC-Q101 qualification | Identical performance; differs only in material composition (halogen-free molding compound) | Select when halogen-free compliance is mandated by OEM environmental specifications |
| SMBJ18CAHE3_A/I | Same VWM/VBR/VC, but SMB (DO-214AA) package - 27% larger footprint, 600 W PPPM rating | Higher power handling; requires larger PCB pad area and different thermal layout | Choose when system-level surge testing exceeds 400 W or when higher IPPM margin is needed |
Compared with SMAJ18CAHE3_A/I, the SMAJ18CA-M3/5A offers identical protection performance with halogen-free construction, while the SMBJ18CAHE3_A/I provides 50% higher peak pulse power in a physically larger package - enabling trade-offs between board space, environmental compliance, and surge margin.
Availability
SMAJ18CAHE3_A/I is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial CAN bus nodes, consumer USB ports, and telecom power supply inputs requiring stable component supply, AEC-Q101 validation, and consistent TVS clamping performance across production batches.
Supply support for SMAJ18CAHE3_A/I 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, MOSFETs, optoelectronics, and passive components with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series is engineered for high-reliability transient suppression in automotive, industrial, and communications systems - delivering precise clamping, AEC-Q101 qualification, and robust surge handling in compact surface-mount packages.
FAQ
What is the clamping voltage of SMAJ18CAHE3_A/I at its rated peak pulse current?
The SMAJ18CAHE3_A/I clamps to a maximum of 29.2 V at its specified peak pulse current of 13.7 A (10/1000 μs waveform). This value is measured under standardized test conditions and defines the upper voltage limit imposed on protected circuitry during surge events. The SMAJ18CAHE3_A/I maintains this clamping performance across its full operating temperature range of –55 °C to +150 °C.
Is SMAJ18CAHE3_A/I suitable for automotive applications?
Yes, SMAJ18CAHE3_A/I is AEC-Q101 qualified and explicitly designated for automotive use in Vishay's ordering nomenclature (HE3 suffix). It meets stress test requirements for temperature cycling, humidity, mechanical shock, and surge endurance - making it appropriate for engine control units, body electronics, and ADAS sensor modules where reliability under harsh conditions is critical. The SMAJ18CAHE3_A/I also complies with RoHS and supports lead-free reflow.
How does the bidirectional design of SMAJ18CAHE3_A/I affect its circuit implementation?
The bidirectional configuration of SMAJ18CAHE3_A/I allows it to protect AC-coupled or floating signal paths without regard to polarity - it conducts equally during positive and negative voltage excursions beyond VBR. Unlike unidirectional TVS diodes, SMAJ18CAHE3_A/I has no cathode band marking and is installed symmetrically across protected lines (e.g., CANH–CANL or RS-485 A–B). This simplifies layout and eliminates orientation errors during automated assembly.
What is the thermal resistance of SMAJ18CAHE3_A/I, and how does it impact PCB layout?
SMAJ18CAHE3_A/I has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and junction-to-lead resistance (RθJL) of 30 °C/W. These values assume mounting on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain safe junction temperatures under repetitive surges, designers must adhere to this minimum pad layout - reducing pad size increases RθJA and risks thermal runaway. The SMAJ18CAHE3_A/I does not require external heatsinking in compliant layouts.
Does SMAJ18CAHE3_A/I meet industry standards for surge immunity testing?
Yes, SMAJ18CAHE3_A/I is characterized for 10/1000 μs waveform surge testing per ANSI/IEEE C62.35 and supports system-level compliance with IEC 61000-4-5 (lightning surge), ISO 7637-2 (automotive transients), and IEC 61000-4-2 (ESD). Its 400 W peak pulse power rating corresponds to 4 kV/2 Ω coupling in IEC 61000-4-5 Level 4 testing on 12 V systems. The SMAJ18CAHE3_A/I's fast response time (<1 ns) ensures effective clamping before downstream ICs experience overstress.
SMAJ18CAHE3_A/I Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- Voltage - Reverse Standoff (Typ):
- 18V
- Voltage - Breakdown (Min):
- 20V
- Voltage - Clamping (Max) @ Ipp:
- 29.2V
- Current - Peak Pulse (10/1000µs):
- 13.7A
- 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)
SMAJ18CAHE3_A/I FAQ
1.How can I place an order for SMAJ18CAHE3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18CAHE3_A/I 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 SMAJ18CAHE3_A/I reliable?
The price and inventory of SMAJ18CAHE3_A/I are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18CAHE3_A/I is usually 5 days.
3.What payment methods are accepted for SMAJ18CAHE3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18CAHE3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18CAHE3_A/I?
SMAJ18CAHE3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18CAHE3_A/I 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 SMAJ18CAHE3_A/I?
For technical support, including SMAJ18CAHE3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18CAHE3_A/I requirements.
6.How does Aetrix verify that SMAJ18CAHE3_A/I is sourced from the original manufacturer or authorized distributors?
All SMAJ18CAHE3_A/I 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 SMAJ18CAHE3_A/I meets industry standards.
7.What is the process for return or replacement of SMAJ18CAHE3_A/I?
All SMAJ18CAHE3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18CAHE3_A/I, 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 SMAJ18CAHE3_A/I part is unused and in its original packaging.
Return procedure for SMAJ18CAHE3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ18CAHE3_A/I Tags
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