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Vishay General Semiconductor - Diodes Division SMA5J18A-M3/5A
- Part No.:
- SMA5J18A-M3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA5J18A-M3/5A.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SMA5J18A-M3/5A from Vishay General Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for high-energy surge protection on power and signal lines. It features 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR), 500 W peak pulse power (PPPM), and clamps transients to ≤29.2 V at 17.1 A IPPM - deployed in automotive sensor interfaces, industrial I/O protection, and DC power rail conditioning.
For engineers reviewing the SMA5J18A-M3/5A datasheet, SMA5J18A-M3/5A pinout, SMA5J18A-M3/5A application, or SMA5J18A-M3/5A equivalent, key selection criteria include unidirectional polarity, 150 °C max junction temperature, halogen-free RoHS compliance (M3 suffix), and compatibility with automated SMT placement on 5.0 mm × 5.0 mm copper pads.
Technical Context
This TVS diode operates as a clamping device triggered by reverse-biased avalanche breakdown above VWM. Its glass-passivated junction ensures stable leakage (<1.0 μA at 18 V) and fast response (<1 ns), while low incremental surge resistance enables effective energy diversion during 10/1000 μs transients.
Rated for 500 W peak pulse power under standardized waveform conditions and derated linearly above 25 °C ambient, it supports robust protection in environments with repetitive switching surges - including inductive load switching in 12 V/24 V automotive systems and industrial PLC inputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before clamping begins; sets threshold for protection of 15–18 V nominal rails. |
| VBR min/max | 20.0 V / 22.1 V at 1 mA - verified avalanche onset range; ensures predictable turn-on without premature conduction. |
| VC @ IPPM | ≤29.2 V at 17.1 A - clamping voltage under full-rated 10/1000 μs surge; limits downstream voltage stress to safe levels. |
| PPPM | 500 W - peak transient power handling capability; supports EN 61000-4-5 Level 4 (4 kV) surge immunity when properly laid out. |
| ID @ VWM | ≤1.0 μA - ultra-low reverse leakage at stand-off; preserves efficiency in battery-powered or high-impedance sensing circuits. |
| TJ max | +150 °C - maximum junction temperature; enables operation in under-hood automotive or enclosed industrial enclosures. |
| RθJA | 80 °C/W - thermal resistance junction-to-ambient on standard 5.0 mm × 5.0 mm pads; informs heatsinking requirements for repeated surge events. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, halogen-free, RoHS-compliant, M3 suffix. Cathode indicated by band; anode and cathode terminals are axially oriented along the body axis.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Forward current entry / reverse surge return path | Connected to protected line's lower-potential side (e.g., GND or return rail); completes clamping loop during transient. |
| Cathode | Avalanche conduction node / surge sink | Connected to protected line's higher-potential side (e.g., VCC or signal line); conducts surge current into anode/GND when V > VBR. |
Key Features
| Feature | Design Value |
|---|---|
| Low-profile SMA package | Enables compact PCB layout in space-constrained modules (e.g., ADAS camera ECUs or motor drive control boards). |
| Glass-passivated junction | Ensures long-term reliability and stable VBR over temperature and lifetime, critical for automotive AEC-Q101-aligned designs. |
| MSL Level 1 rating | Allows unlimited floor life and reflow at 260 °C peak - compatible with standard lead-free SMT assembly without baking. |
| 500 W peak pulse power | Provides margin against ISO 7637-2 Pulse 5a (load dump) and IEC 61000-4-5 surges in 12 V/24 V systems. |
| Halogen-free (M3) | Meets stringent environmental compliance (IEC 61249-2-21) for industrial and automotive supply chains requiring green materials. |
Applications
| Automotive Sensor Protection | Industrial PLC Input Protection |
|---|---|
Use Scenario: Protecting CAN/LIN bus transceivers and analog sensor front-ends (e.g., pressure, temperature) from load dump and ESD in engine control units. IC Role / Device Role / Timing Role: Unidirectional TVS clamp placed between sensor signal line and chassis ground, absorbing transients before they reach precision amplifier inputs. Use Value: Limits voltage excursion to ≤29.2 V during 17.1 A surge, preventing latch-up or damage to 3.3 V/5 V interface ICs while maintaining <1.0 μA leakage at 18 V bias. |
Use Scenario: Safeguarding digital input channels of programmable logic controllers exposed to inductive kickback from solenoid valves and relay coils. IC Role / Device Role / Timing Role: Standoff-rated TVS connected across input terminal and common rail to shunt 500 W surges away from optocoupler or Schmitt trigger input stages. Use Value: Clamps 10/1000 μs transients to ≤29.2 V within nanoseconds, enabling reliable operation in noisy factory environments without false triggering or component degradation. |
| DC Power Rail Conditioning | Consumer Device USB Port Protection |
Use Scenario: Secondary overvoltage protection on 12 V or 24 V DC distribution rails feeding motor drivers, lighting controllers, or communication modules. IC Role / Device Role / Timing Role: Parallel-connected TVS providing fail-safe clamping after primary fuse or polyfuse, limiting rail voltage during sustained overvoltage events. Use Value: Withstands 500 W pulses and operates up to +150 °C junction temperature, supporting continuous duty-cycle protection in thermally demanding power subsystems. |
Use Scenario: Reverse-polarity and surge protection on 5 V USB VBUS lines in portable medical monitors or smart home hubs. IC Role / Device Role / Timing Role: Unidirectional TVS placed between VBUS and GND to block reverse connection and clamp ESD/inductive spikes induced by hot-plug events. Use Value: Delivers <1.0 μA leakage at 18 V stand-off and sub-1 ns response, preserving USB enumeration integrity while meeting IEC 61000-4-2 Level 4 (15 kV air) requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA5J18A-E3/5A | Same electrical specs, but RoHS-compliant commercial grade (E3) without halogen-free certification; no M3 material compliance. | Approved for non-automotive industrial or consumer use where halogen-free mandate is not enforced. | Select SMA5J18A-E3/5A only if halogen-free requirement is waived and cost optimization is prioritized. |
| SMA6J18A-M3/5A | Higher PPPM (600 W vs. 500 W), same VWM/VBR/VC, identical SMA package and M3 suffix; requires verification of board-level thermal margin. | Better suited for systems facing higher-energy surges (e.g., heavy-duty vehicle alternator load dump) where extra power headroom is needed. | Choose SMA6J18A-M3/5A when design margins demand ≥600 W surge rating and thermal layout supports increased dissipation. |
Compared with SMA5J18A-M3/5A, the E3 variant trades halogen-free compliance for lower cost in non-regulated applications, while the SMA6J18A-M3/5A delivers 20 % higher pulse power without changing footprint - both require separate validation of layout thermal performance and system-level surge test compliance.
Availability
SMA5J18A-M3/5A is available at Aetrix Electronics and suitable for automotive sensor interfaces, industrial PLC inputs, and DC power rail conditioning requiring stable component supply, halogen-free compliance, and AEC-Q101-aligned reliability.
Supply support for SMA5J18A-M3/5A 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 reliability, power density, and automotive-grade qualification.
The SMA5J series is engineered for high-power-density transient suppression in harsh environments - targeting 12 V/24 V automotive, industrial automation, and telecom infrastructure where compact size, thermal robustness, and repeatable clamping are essential.
FAQ
What is the polarity configuration of the SMA5J18A-M3/5A?
The SMA5J18A-M3/5A is a unidirectional transient voltage suppressor diode. Its cathode is marked by a band on the SMA (DO-214AC) package body. When installed correctly - cathode toward the protected line's higher potential - it clamps reverse transients while blocking forward current below its forward voltage threshold. This polarity must be observed to ensure proper surge diversion in the SMA5J18A-M3/5A circuit implementation.
Does the SMA5J18A-M3/5A meet AEC-Q101 qualification?
No, the SMA5J18A-M3/5A is not AEC-Q101 qualified. It carries the M3 suffix indicating halogen-free, RoHS-compliant commercial grade construction. For automotive-qualified versions, Vishay offers the SMA5J18AHM3_A/H or SMA5J18AHM3_A/I variants - these include the HM3 suffix and explicit AEC-Q101 qualification noted in the ordering code and datasheet revision notes.
What is the maximum clamping voltage of the SMA5J18A-M3/5A under rated surge conditions?
The SMA5J18A-M3/5A has a maximum clamping voltage (VC) of 29.2 V when subjected to its rated peak pulse current (IPPM) of 17.1 A under the standard 10/1000 μs waveform. This value is measured at TJ = 25 °C and reflects worst-case clamping performance used for downstream component voltage stress analysis in the SMA5J18A-M3/5A protection circuit.
How does the thermal resistance of the SMA5J18A-M3/5A affect its surge handling capability?
The SMA5J18A-M3/5A 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. This value directly impacts how many consecutive surges the SMA5J18A-M3/5A can absorb without exceeding its 150 °C maximum junction temperature - higher RθJA reduces permissible surge repetition rate unless additional copper area or thermal vias are added.
Can the SMA5J18A-M3/5A be used in bidirectional protection applications?
No, the SMA5J18A-M3/5A is strictly unidirectional. For bidirectional transient suppression - such as AC signal lines or differential buses - Vishay specifies the SMA5J18CA family (e.g., SMA5J18CA-M3/5A), which uses the CA suffix and exhibits symmetrical clamping in both polarities. Using SMA5J18A-M3/5A in bidirectional roles will result in forward conduction and failure during negative transients.
SMA5J18A-M3/5A Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Package/Case:
- DO-214AC, SMA
- Series:
- TransZorb®
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- Zener
- Unidirectional Channels:
- 1
- Bidirectional Channels:
- -
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMA5J18A-M3/5A FAQ
1.How can I place an order for SMA5J18A-M3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA5J18A-M3/5A 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 SMA5J18A-M3/5A reliable?
The price and inventory of SMA5J18A-M3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA5J18A-M3/5A is usually 5 days.
3.What payment methods are accepted for SMA5J18A-M3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA5J18A-M3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA5J18A-M3/5A?
SMA5J18A-M3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA5J18A-M3/5A 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 SMA5J18A-M3/5A?
For technical support, including SMA5J18A-M3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA5J18A-M3/5A requirements.
6.How does Aetrix verify that SMA5J18A-M3/5A is sourced from the original manufacturer or authorized distributors?
All SMA5J18A-M3/5A 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 SMA5J18A-M3/5A meets industry standards.
7.What is the process for return or replacement of SMA5J18A-M3/5A?
All SMA5J18A-M3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMA5J18A-M3/5A, 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 SMA5J18A-M3/5A part is unused and in its original packaging.
Return procedure for SMA5J18A-M3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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