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Vishay General Semiconductor - Diodes Division SMA6J18A-E3/5A
- Part No.:
- SMA6J18A-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMA6J18A-E3/5A.pdf
- Description:
- TVS DIODE 18VWM 33.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:8,883
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Product details
Overview
SMA6J18A-E3/5A from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on power and signal lines. It features a 18 V stand-off voltage (VWM), 20.0–22.1 V breakdown voltage (VBR at IT = 1 mA), 28.3 V maximum clamping voltage at 10/1000 μs IPPM = 21.2 A, and 600 W peak pulse power rating. It protects MOSFETs, ICs, and sensor signal lines in industrial and telecom equipment against inductive switching surges.
For engineers reviewing the SMA6J18A-E3/5A datasheet, SMA6J18A-E3/5A pinout, SMA6J18A-E3/5A application, or SMA6J18A-E3/5A equivalent, key selection criteria include unidirectional polarity, 28.3 V clamping at 21.2 A (10/1000 μs), SMA package thermal resistance (RθJA = 120 °C/W), 0.292 Ω dynamic resistance, and compliance with J-STD-020 MSL level 1.
Technical Context
This TVS diode operates as a voltage-clamped crowbar device triggered above its breakdown threshold, using avalanche breakdown to shunt transient energy away from protected circuitry. Its low dynamic resistance (0.292 Ω) ensures minimal voltage overshoot during high-current transients, while its 120 °C/W junction-to-ambient thermal resistance requires PCB copper pad thermal management per recommended 5.0 mm × 5.0 mm layout.
The SMA6J18A-E3/5A is rated for 4 W steady-state power dissipation at TA = 50 °C and supports 50 A non-repetitive forward surge current (IFSM, 8.3 ms half-sine). It exhibits a positive voltage temperature coefficient (αT = 9.2 × 10⁻⁴ /°C), enabling predictable VBR drift over -55 °C to +150 °C operating range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse voltage before leakage exceeds 0.2 μA; defines safe operating margin below clamping onset. |
| VBR (min/max) | 20.0 V / 22.1 V at IT = 1 mA - Confirmed avalanche initiation window; sets minimum trigger threshold under production tolerance. |
| VC at IPPM | 28.3 V at 21.2 A (10/1000 μs) - Clamped voltage seen by protected IC during worst-case surge; determines downstream voltage stress. |
| PPPM (10×1000 μs) | 600 W - Peak transient energy handling capacity under standard lightning/surge waveform; defines protection robustness. |
| RD | 0.292 Ω - Dynamic resistance governing voltage rise ΔV = RD × ΔI during transient; lower value improves clamping precision. |
| TJ max. | +150 °C - Maximum junction temperature limit; constrains PCB thermal design and derating above TA = 25 °C. |
| IFSM | 50 A - Single half-sine surge current rating (8.3 ms); validates survivability during inrush or fault events. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, unidirectional polarity with cathode indicated by color band. Molded compound meets UL 94 V-0; matte tin-plated leads compliant with J-STD-002 solderability.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Transient current sink path | Connected to protected line (e.g., VCC or signal); conducts during reverse-biased avalanche event. |
| Cathode | Reference node / clamp return | Connected to ground or low-impedance reference; completes current path during clamping; marked by band. |
Key Features
| Feature | Design Value |
|---|---|
| Clamping performance | 28.3 V VC at 21.2 A (10/1000 μs) enables reliable protection of 24 V systems without overvoltage damage to downstream ICs. |
| Thermal reliability | MSL level 1 rating and 260 °C lead-free reflow compatibility ensure robust automated assembly without popcorn cracking. |
| Leakage control | ≤0.2 μA ID at 18 V VWM minimizes standby power loss and avoids false triggering in low-power sensor interfaces. |
| Dynamic response | Sub-nanosecond response time (inherent to avalanche diode physics) captures fast transients before protected devices react. |
| PCB integration | SMA footprint supports high-density layouts; 5.0 mm × 5.0 mm copper pads per terminal reduce thermal impedance to 120 °C/W. |
Applications
| Industrial Motor Drives | Telecom Power Supplies |
|---|---|
Use Scenario: Protection of gate drivers and DC bus sensing circuits against inductive kickback from relay and solenoid switching. IC Role / Device Role: Unidirectional TVS clamping transient spikes on 24 V control rails and feedback paths. Use Value: Prevents latch-up or permanent damage to isolated amplifiers and PWM controllers exposed to >1 kV transients. |
Use Scenario: Input-stage surge suppression on 48 V telecom rectifier outputs subjected to lightning-induced surges per IEC 61000-4-5. IC Role / Device Role: Primary clamping element absorbing 600 W (10/1000 μs) energy before downstream DC/DC converters. Use Value: Maintains system uptime by limiting input rail excursion to ≤28.3 V during 21.2 A surge events. |
| Automotive Body Control Modules | Industrial Sensor Interfaces |
Use Scenario: Reverse battery and load dump protection on LIN bus power rails and microcontroller supply inputs. IC Role / Device Role: Standoff-rated TVS absorbing 50 A IFSM surges while maintaining 18 V nominal operation. Use Value: Eliminates need for additional series fusing or active protection ICs in cost-sensitive BCM designs. |
Use Scenario: ESD and EFT hardening of analog sensor signal lines (e.g., pressure, temperature) in factory automation PLCs. IC Role / Device Role: Low-leakage (0.2 μA) clamping device preserving signal integrity on mV-level sensor outputs. Use Value: Enables direct connection to 16-bit ADCs without gain error from leakage-induced offset drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMA6J18CA-E3/5A | Bidirectional variant with symmetrical ±20.0 V breakdown; higher capacitance (≈13.6 pF vs. unidirectional's ≈7.0 pF). | Required where AC-coupled or bidirectional signal lines (e.g., RS-485, CAN) need symmetric clamping. | Select only if polarity reversal or AC transients are present; not drop-in for DC-only rails. |
| SMCJ18A-E3/57T | Higher power rating (1500 W PPPM), larger SMC (DO-214AB) package, RθJA = 30 °C/W, same VWM/VBR specs. | Suitable for higher-energy surges where board space allows larger footprint and improved thermal performance. | Choose when 600 W is insufficient and thermal budget permits SMC package; no PCB redesign needed if pad layout accommodates. |
Compared with SMA6J18A-E3/5A, SMA6J18CA-E3/5A adds bidirectional capability at the cost of higher junction capacitance, while SMCJ18A-E3/57T delivers 2.5× higher surge power in a thermally superior but physically larger package-both require explicit validation for pin compatibility and layout fit.
Availability
SMA6J18A-E3/5A is available at Aetrix Electronics and suitable for industrial motor drives, telecom power supplies, and automotive body control modules requiring stable component supply, RoHS-compliant packaging, and MSL level 1 reflow readiness.
Supply support for SMA6J18A-E3/5A 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, TVS devices, and optoelectronics with emphasis on reliability and industrial-grade qualification.
The SMA6J18A-E3/5A belongs to Vishay's TRANSZORB® family of transient suppressors, engineered specifically for high-reliability clamping in harsh environments including factory automation, telecom infrastructure, and vehicle electronics.
FAQ
What is the maximum clamping voltage of the SMA6J18A-E3/5A under a 10/1000 μs surge?
The SMA6J18A-E3/5A has a maximum clamping voltage (VC) of 28.3 V when subjected to a 10/1000 μs waveform at its rated peak pulse current of 21.2 A. This value is measured per JEDEC standards and reflects the actual voltage imposed on protected circuitry during surge events. The SMA6J18A-E3/5A maintains this clamping performance across its specified operating temperature range.
Is the SMA6J18A-E3/5A suitable for 24 V DC power rail protection?
Yes, the SMA6J18A-E3/5A is explicitly designed for 24 V system protection: its 18 V stand-off voltage (VWM) provides adequate margin below 24 V nominal, while its 28.3 V clamping voltage stays safely below typical 30 V absolute maximum ratings of industrial ICs and MOSFETs. The SMA6J18A-E3/5A also withstands 50 A surge currents, making it appropriate for inductive load switching in such rails.
Does the SMA6J18A-E3/5A have a bidirectional variant?
Yes, the SMA6J18CA-E3/5A is the bidirectional counterpart of the SMA6J18A-E3/5A, offering symmetrical ±20.0 V breakdown and clamping in both polarities. However, the SMA6J18A-E3/5A itself is unidirectional only, with cathode marked by a band. The bidirectional version has higher junction capacitance and is intended for AC or differential signal lines-not a direct replacement for DC rail protection.
What is the thermal resistance and recommended PCB layout for the SMA6J18A-E3/5A?
The SMA6J18A-E3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W when mounted on the minimum recommended pad layout: 5.0 mm × 5.0 mm copper pads per terminal. This layout is critical to achieve rated 4 W power dissipation at TA = 50 °C and prevent thermal runaway during repetitive transients. The SMA6J18A-E3/5A datasheet specifies exact dimensions in inches and millimeters.
How does the SMA6J18A-E3/5A compare to the SMCJ18A in terms of surge handling?
The SMA6J18A-E3/5A delivers 600 W peak pulse power (10/1000 μs), whereas the SMCJ18A offers 1500 W-2.5× higher energy absorption. This difference stems from the SMCJ18A's larger SMC package (DO-214AB) and lower RθJA (30 °C/W vs. 120 °C/W). The SMA6J18A-E3/5A remains optimal for space-constrained designs where 600 W suffices; the SMCJ18A is preferred when higher surge immunity is required and board area permits.
SMA6J18A-E3/5A 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:
- 33.2V
- Current - Peak Pulse (10/1000µs):
- 102A (8/20µs)
- Power - Peak Pulse:
- 4000W (4kW)
- 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)
SMA6J18A-E3/5A FAQ
1.How can I place an order for SMA6J18A-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMA6J18A-E3/5A 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 SMA6J18A-E3/5A reliable?
The price and inventory of SMA6J18A-E3/5A are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMA6J18A-E3/5A is usually 5 days.
3.What payment methods are accepted for SMA6J18A-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMA6J18A-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMA6J18A-E3/5A?
SMA6J18A-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMA6J18A-E3/5A 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 SMA6J18A-E3/5A?
For technical support, including SMA6J18A-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMA6J18A-E3/5A requirements.
6.How does Aetrix verify that SMA6J18A-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMA6J18A-E3/5A 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 SMA6J18A-E3/5A meets industry standards.
7.What is the process for return or replacement of SMA6J18A-E3/5A?
All SMA6J18A-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMA6J18A-E3/5A, 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 SMA6J18A-E3/5A part is unused and in its original packaging.
Return procedure for SMA6J18A-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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