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Vishay General Semiconductor - Diodes Division SMA5J18CAHM3_A/I
- Part No.:
- SMA5J18CAHM3_A/I
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA5J18CAHM3_A/I.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:9,469
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Product details
Overview
SMA5J18CAHM3_A/I from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for high-energy surge protection on signal and power lines. It features a 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR), 500 W peak pulse power (10/1000 µs), clamping voltage of 29.2 V at 17.1 A, and operates from –55 °C to +150 °C - used in automotive sensor line protection and industrial I/O interface surge hardening.
For engineers reviewing the SMA5J18CAHM3_A/I datasheet, SMA5J18CAHM3_A/I pinout, SMA5J18CAHM3_A/I application, or SMA5J18CAHM3_A/I equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification status, halogen-free RoHS compliance, 500 W surge rating, and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
This TVS diode employs a glass-passivated silicon junction optimized for fast response (<1 ps) to transient overvoltages and low incremental surge resistance. Its bidirectional architecture enables symmetrical clamping in both polarities without external polarity management, making it suitable for AC-coupled or floating signal paths.
Rated for 500 W peak pulse power under standardized 10/1000 µs waveform conditions, it delivers 29.2 V clamping at 17.1 A IPPM while maintaining <1.0 µA reverse leakage at 18 V. Thermal resistance is 80 °C/W junction-to-ambient (RθJA) when mounted per recommended pad layout.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before clamping begins; defines safe signal swing range for protected line. |
| VBR (min/max) | 20.0 V / 22.1 V at 1 mA - guaranteed breakdown threshold ensures predictable turn-on during transients. |
| VC @ IPPM | 29.2 V at 17.1 A - clamping voltage limits downstream IC stress during 500 W surge events. |
| PPPM | 500 W - peak pulse power handling capacity per 10/1000 µs waveform; determines survivability against lightning-induced surges. |
| TJ range | –55 °C to +150 °C - extended temperature operation supports under-hood automotive and industrial control environments. |
| Package | SMA (DO-214AC) - surface-mount package with 5.28 mm × 4.50 mm footprint, compatible with standard reflow profiles (MSL Level 1, 260 °C peak). |
| Compliance | AEC-Q101 qualified, halogen-free, RoHS-compliant - meets automotive reliability and environmental requirements. |
Pinout & Package
SMA5J18CAHM3_A/I is housed in an SMA (DO-214AC) surface-mount package with two terminals: cathode and anode. As a bidirectional device, it has no polarity marking; both terminals are functionally symmetric and interchangeable in circuit layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current entry point (positive half-cycle) | Conducts surge current during positive voltage excursions; forms one side of symmetrical clamping path. |
| Cathode | Transient current entry point (negative half-cycle) | Conducts surge current during negative voltage excursions; completes bidirectional clamping loop with anode. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC or floating DC lines without polarity constraints or external diode pairing. |
| 500 W peak pulse power | Withstands high-energy transients such as ISO 7637-2 Pulse 5a (load dump) and IEC 61000-4-5 surge events. |
| AEC-Q101 qualification | Validated for automotive applications including engine control units, body electronics, and ADAS sensor interfaces. |
| Halogen-free & RoHS | Meets global environmental regulations and supports lead-free assembly with matte tin-plated leads. |
| Low thermal resistance | RθJA = 80 °C/W allows effective heat dissipation on standard PCB copper pads without heatsinking. |
Applications
| Automotive Sensor Protection | Industrial PLC I/O Protection |
|---|---|
Use Scenario: Protecting CAN, LIN, or analog sensor lines (e.g., oxygen, pressure, temperature sensors) from load dump and ESD in vehicle ECUs. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed across differential or single-ended signal pairs upstream of receiver inputs. Use Value: Limits transient voltage to ≤29.2 V during 500 W surges, preventing damage to automotive-grade microcontrollers and transceivers rated for ≤36 V absolute max. |
Use Scenario: Safeguarding digital input modules in programmable logic controllers exposed to inductive switching noise from solenoids and contactors. IC Role / Device Role / Timing Role: Parallel-connected TVS on field-side signal traces to shunt induced transients before they reach isolation barriers or input conditioning circuits. Use Value: Clamps 17.1 A surge current within 1 ps, reducing risk of latch-up or permanent failure in 24 V DC input stage components. |
| Telecom Line Interface | Consumer Power Adapter Output |
Use Scenario: Surge suppression on Ethernet PHY interface lines or RS-485 bus segments in network equipment subjected to lightning-induced surges. IC Role / Device Role / Timing Role: Low-capacitance bidirectional clamp placed between differential pair and PHY IC, referenced to local ground. Use Value: Maintains signal integrity with minimal added capacitance while meeting IEC 61000-4-5 Level 3 (1 kV/2 kV) immunity requirements. |
Use Scenario: Secondary-side overvoltage protection on 12–19 V DC output rails of wall-mounted power adapters for laptops and monitors. IC Role / Device Role / Timing Role: Final-stage clamp after DC-DC regulation to absorb residual transients from cable disconnect or hot-plug events. Use Value: Prevents output voltage overshoot beyond 29.2 V during 10/1000 µs surges, protecting connected devices with 20 V absolute maximum ratings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA5J18CAHE3_A/I | Same electrical specs and package; RoHS-compliant but not halogen-free; lacks AEC-Q101 qualification. | Suitable for commercial/industrial use where automotive qualification is not required. | Select when halogen-free content or AEC-Q101 certification is unnecessary and cost optimization is prioritized. |
| SMA6J18CAHM3_A/I | 600 W peak pulse power (vs. 500 W); identical VWM, VBR, VC, and package; same AEC-Q101/halogen-free status. | Preferred for higher-surge-risk environments (e.g., heavy-duty vehicle alternator lines or factory floor motor drives). | Choose when system-level surge testing exceeds 500 W requirements or margin extension is needed without layout change. |
Compared with SMA5J18CAHM3_A/I, SMA5J18CAHE3_A/I offers identical protection performance without halogen-free or automotive qualification, while SMA6J18CAHM3_A/I provides 20 % higher surge power headroom in the same footprint - enabling design reuse with enhanced robustness.
Availability
SMA5J18CAHM3_A/I is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC I/O modules, and telecom line protection requiring stable component supply, long-term lifecycle support, and traceable sourcing for production programs.
Supply support for SMA5J18CAHM3_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, rectifiers, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.
The SMA5J series is part of Vishay's TRANSZORB® TVS platform, engineered for high-power-density transient suppression in space-constrained automotive and industrial systems where fast response and repeatable clamping are critical.
FAQ
What is the clamping voltage of SMA5J18CAHM3_A/I at its rated peak pulse current?
The SMA5J18CAHM3_A/I clamps to a maximum of 29.2 V at its specified peak pulse current of 17.1 A under 10/1000 µs waveform conditions. This value is measured per JEDEC standards and guarantees consistent overvoltage limiting behavior across production lots and temperature ranges from –55 °C to +150 °C. The SMA5J18CAHM3_A/I achieves this with low dynamic impedance, ensuring reliable protection for downstream 3.3 V or 5 V logic interfaces.
Is SMA5J18CAHM3_A/I suitable for automotive applications?
Yes, SMA5J18CAHM3_A/I is AEC-Q101 qualified and specifically intended for automotive use, including engine control units, body electronics, and ADAS sensor interfaces. Its halogen-free, RoHS-compliant construction and MSL Level 1 moisture sensitivity rating support robust manufacturing and long-term reliability in under-hood environments. The SMA5J18CAHM3_A/I meets stringent automotive surge and ESD immunity requirements when applied per Vishay's recommended layout guidelines.
How does the bidirectional design of SMA5J18CAHM3_A/I affect circuit implementation?
The bidirectional design of SMA5J18CAHM3_A/I eliminates polarity marking and allows placement across any two-node connection without orientation concerns - ideal for AC-coupled lines, differential buses like RS-485, or floating sensor outputs. Unlike unidirectional TVS diodes, the SMA5J18CAHM3_A/I provides symmetrical clamping in both directions, simplifying schematic capture and PCB routing while maintaining identical VBR and VC characteristics for positive and negative transients.
What is the thermal resistance of SMA5J18CAHM3_A/I, and how does it impact layout?
SMA5J18CAHM3_A/I has a typical junction-to-ambient thermal resistance (RθJA) of 80 °C/W when mounted on 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. This value assumes standard FR-4 PCB construction and convection cooling only. To maintain safe junction temperatures during repetitive surges, designers must adhere to Vishay's recommended pad dimensions and avoid excessive copper removal near the SMA5J18CAHM3_A/I footprint - no additional heatsinking is required for single-event protection.
Does SMA5J18CAHM3_A/I require derating at elevated ambient temperatures?
Yes, SMA5J18CAHM3_A/I requires derating above 25 °C ambient temperature, as shown in Figure 2 of the Vishay datasheet (Document Number: 88875). At 85 °C ambient, its peak pulse power capability reduces to approximately 350 W, and at 125 °C, it drops to ~200 W. These derating curves apply to both single-pulse and repetitive surge conditions. System-level thermal modeling should include the SMA5J18CAHM3_A/I's RθJA and expected duty cycle to ensure sustained reliability.
SMA5J18CAHM3_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):
- 17.1A
- Power - Peak Pulse:
- 500W
- Power Line Protection:
- No
- Applications:
- Telecom
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q101
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMA5J18CAHM3_A/I FAQ
1.How can I place an order for SMA5J18CAHM3_A/I through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA5J18CAHM3_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 SMA5J18CAHM3_A/I reliable?
The price and inventory of SMA5J18CAHM3_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 SMA5J18CAHM3_A/I is usually 5 days.
3.What payment methods are accepted for SMA5J18CAHM3_A/I?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA5J18CAHM3_A/I transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA5J18CAHM3_A/I?
SMA5J18CAHM3_A/I orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA5J18CAHM3_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 SMA5J18CAHM3_A/I?
For technical support, including SMA5J18CAHM3_A/I datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA5J18CAHM3_A/I requirements.
6.How does Aetrix verify that SMA5J18CAHM3_A/I is sourced from the original manufacturer or authorized distributors?
All SMA5J18CAHM3_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 SMA5J18CAHM3_A/I meets industry standards.
7.What is the process for return or replacement of SMA5J18CAHM3_A/I?
All SMA5J18CAHM3_A/I units undergo pre-shipment inspection (PSI). If there is an issue with SMA5J18CAHM3_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 SMA5J18CAHM3_A/I part is unused and in its original packaging.
Return procedure for SMA5J18CAHM3_A/I:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMA5J18CAHM3_A/I Tags
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