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Vishay General Semiconductor - Diodes Division SMAJ18C-E3/5A
- Part No.:
- SMAJ18C-E3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18C-E3/5A.pdf
- Description:
- TVS DIODE 18VWM 32.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:2,326
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Product details
Overview
SMAJ18C-E3/5A from Vishay General Semiconductor is a bi-directional surface-mount Transient Voltage Suppressor (TVS) in DO-214AC (SMA) package, designed for clamping voltage transients on signal or power lines. It features a 18 V stand-off voltage (VWM), 20.0–24.4 V breakdown voltage (VBR), 32.2 V maximum clamping voltage (VC) at 12.4 A peak pulse current, and 400 W peak pulse power rating with 10/1000 µs waveform - used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial control systems.
For engineers reviewing the SMAJ18C-E3/5A datasheet, SMAJ18C-E3/5A pinout, SMAJ18C-E3/5A application, or SMAJ18C-E3/5A equivalent, this page delivers verified electrical parameters, bi-directional TVS behavior, DO-214AC mechanical data, clamping performance under surge conditions, and direct alternatives for ESD/lightning transient protection in 12 V and 24 V rail designs.
Technical Context
This bi-directional TVS diode operates symmetrically in both polarities, with no polarity marking on the device body. Its glass-passivated junction enables fast response (<1 ns) to transients and low incremental surge resistance, critical for suppressing inductive switching spikes and ESD events per IEC 61000-4-2/4-4.
The device is rated for 150 °C maximum junction temperature and meets MSL Level 1 per J-STD-020, supporting lead-free reflow up to 260 °C. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), confirming suitability for compact PCB layouts with minimal copper pad area (0.2" × 0.2").
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - Maximum continuous reverse working voltage before clamping begins; defines safe operating margin for 12 V nominal systems. |
| VBR min/max | 20.0 V / 24.4 V at 1 mA - Confirmed breakdown threshold range; ensures reliable turn-on during overvoltage events above system rail. |
| VC @ IPPM | 32.2 V at 12.4 A - Clamped voltage under 10/1000 µs surge; limits stress on downstream 33 V-tolerant components. |
| PPPM | 400 W - Peak pulse power handling (≤0.01% duty cycle); supports repetitive surge immunity in motor drive and power supply inputs. |
| IPPM | 12.4 A - Peak pulse current capacity; derived from 10/1000 µs waveform and VC, defining surge energy absorption capability. |
| ID @ VWM | 1.0 µA - Reverse leakage at 18 V; negligible bias current, preserving signal integrity on high-impedance sensor lines. |
| TJ range | −55 °C to +150 °C - Full industrial/automotive temperature operation; validated for under-hood and factory-floor environments. |
Pinout & Package
Package: DO-214AC (SMA), surface-mount, bi-directional configuration with unmarked body (no cathode band). Matte tin-plated leads, RoHS-compliant, MSL Level 1, compatible with J-STD-002 solderability and JESD22-B102.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (symmetrical) | Bi-directional transient conduction path | No polarity distinction; either terminal serves as anode or cathode depending on transient polarity - simplifies layout and eliminates orientation errors. |
Key Features
| Feature | Design Value |
|---|---|
| Bi-directional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity constraints - e.g., RS-485, CAN, or sensor differential pairs. |
| 400 W peak pulse power | Handles 10/1000 µs surges up to 12.4 A while limiting VC to 32.2 V - sufficient for ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Level 3. |
| Glass-passivated junction | Ensures stable VBR and low leakage across temperature and lifetime - critical for long-term reliability in automotive ECUs and industrial PLCs. |
| MSL Level 1 & 260 °C reflow | Supports standard lead-free SMT assembly without moisture sensitivity concerns or pre-bake requirements - reduces manufacturing overhead. |
| RoHS-compliant, JESD201 Class 1A | Meets global environmental compliance and mitigates tin whisker risk in high-reliability applications including automotive and medical-grade peripherals. |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
|
Use Scenario: Suppressing load-dump and jump-start transients on 12 V battery-fed ECUs and body control modules. IC Role / Device Role / Timing Role: Bi-directional TVS placed at connector entry point to clamp ±100 V spikes within 1 ns, protecting LDOs and microcontrollers. Use Value: Limits clamped voltage to 32.2 V - below absolute maximum ratings of common 3.3 V/5 V logic and analog front-ends powered from local regulators. |
Use Scenario: Shielding 4–20 mA current-loop transmitters and RTD interfaces from ESD and field-wiring induced noise. IC Role / Device Role / Timing Role: Placed across input terminals to shunt transients before they reach precision op-amps or ADC drivers. Use Value: 1.0 µA leakage at 18 V avoids loading high-impedance sensor bridges or current-sense resistors, preserving measurement accuracy. |
| Telecom Data Line Surge Protection | Consumer USB Port ESD Clamp |
|
Use Scenario: Protecting Ethernet PHY magnetics and PoE injectors against lightning-induced surges on outdoor cabling. IC Role / Device Role / Timing Role: Paired with common-mode chokes to absorb differential-mode surges on twisted-pair lines. Use Value: 400 W pulse rating sustains multiple 10/1000 µs events per IEC 61000-4-5, enabling robust outdoor deployment without derating. |
Use Scenario: Adding secondary-level ESD protection on USB 2.0 D+/D− lines behind integrated port controllers. IC Role / Device Role / Timing Role: Low-capacitance bi-directional clamp (typ. <100 pF at 0 V) minimizing signal distortion on 480 Mbps data paths. Use Value: Symmetric clamping prevents DC bias shift on differential signals - maintaining eye diagram integrity and USB-IF compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bi-directional TVS protection applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18CA-E3/5A | Same electrical specs and DO-214AC package; "CA" suffix explicitly denotes bi-directional variant per Vishay naming convention (vs. "C" in SMAJ18C-E3/5A). | No functional difference - both are bi-directional; "CA" is Vishay's standardized designation for all bi-directional SMAJ devices. | Select SMAJ18CA-E3/5A if BOM alignment with Vishay's official bi-directional part numbering is required for procurement or documentation traceability. |
| SMCJ18CA | Higher 1500 W peak power rating, larger DO-214AB (SMC) package, 38.9 V clamping voltage at 38.9 A - not pin-compatible. | Used where higher surge energy (e.g., 10/1000 µs >100 A) must be absorbed; requires PCB redesign due to 7.11 mm × 6.22 mm footprint vs. SMA's 4.5 mm × 2.79 mm. | Choose SMCJ18CA only when system-level surge testing exceeds 400 W - otherwise SMAJ18C-E3/5A offers optimal size/power balance for space-constrained boards. |
Compared with SMAJ18CA-E3/5A, the SMAJ18C-E3/5A shares identical electrical behavior but uses legacy "C" bi-directional coding; versus SMCJ18CA, it trades surge capacity for 60 % smaller footprint and lower thermal mass - making it preferable for consumer and portable electronics where board area and weight are critical.
Availability
SMAJ18C-E3/5A is available at Aetrix Electronics and suitable for automotive power line protection, industrial sensor interface protection, telecom data line surge protection, and consumer USB port ESD clamp applications requiring stable component supply across production lifecycles.
Supply support for SMAJ18C-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, MOSFETs, and protection devices with emphasis on reliability, efficiency, and AEC-Q qualified solutions.
The SMAJ series is engineered for robust transient suppression in harsh environments - targeting automotive, industrial, and telecom infrastructure where repeatable clamping, low leakage, and MSL-1 assembly compatibility are mandatory.
FAQ
What does the "C" suffix in SMAJ18C-E3/5A indicate?
The "C" suffix in SMAJ18C-E3/5A designates a bi-directional Transient Voltage Suppressor, confirmed by Vishay's documentation stating "C or CA suffix (e.g. SMAJ10C, SMAJ10CA)" for bi-directional use. Electrical characteristics apply identically in both directions, and the device has no polarity marking - unlike uni-directional variants that feature a cathode band. This makes SMAJ18C-E3/5A suitable for AC-coupled or floating signal lines where voltage polarity may reverse.
Is SMAJ18C-E3/5A RoHS compliant and qualified for automotive use?
Yes, SMAJ18C-E3/5A is RoHS 2002/95/EC compliant and manufactured with matte tin-plated leads meeting J-STD-002 and JESD22-B102. While the base "E3" suffix denotes commercial-grade RoHS compliance (JESD201 Class 1A whisker test), it is not AEC-Q101 qualified - that status applies only to "HE3" suffix variants like SMAJ18CAHE3/5A. For non-automotive industrial or consumer use, SMAJ18C-E3/5A meets full environmental and solderability requirements.
What is the clamping voltage of SMAJ18C-E3/5A under surge conditions?
The maximum clamping voltage (VC) of SMAJ18C-E3/5A is 32.2 V at 12.4 A peak pulse current (IPPM) with a 10/1000 µs waveform. This value is measured per Fig. 1 and Fig. 3 in Vishay document 88390 and represents the upper limit of voltage seen by protected circuitry during a standardized surge event - ensuring downstream 33 V-rated components remain within safe operating limits.
How does SMAJ18C-E3/5A differ from SMAJ18A-E3/5A?
SMAJ18C-E3/5A is bi-directional, whereas SMAJ18A-E3/5A is uni-directional with a cathode band marking. Their key electrical differences include: SMAJ18C-E3/5A has symmetric VBR (20.0–24.4 V) and no polarity; SMAJ18A-E3/5A has asymmetric behavior - forward conduction below ~1 V and reverse clamping only. Clamping voltage also differs: SMAJ18A-E3/5A is 29.2 V at 13.7 A. Thus, SMAJ18C-E3/5A is selected for bidirectional signal lines; SMAJ18A-E3/5A for DC rails with defined polarity.
What PCB pad layout is recommended for SMAJ18C-E3/5A?
Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad area per terminal for SMAJ18C-E3/5A to achieve its rated 400 W peak pulse power. The DO-214AC (SMA) package outline shows 0.157" (3.99 mm) body width and 0.208" (5.28 mm) length; pad extensions beyond footprint improve thermal dissipation. Use of thermal reliefs is discouraged - solid copper connections maximize surge current handling and minimize localized heating during transient events.
SMAJ18C-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:
- Obsolete
- Type:
- Zener
- Unidirectional Channels:
- -
- Bidirectional Channels:
- 1
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ18C-E3/5A FAQ
1.How can I place an order for SMAJ18C-E3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18C-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 SMAJ18C-E3/5A reliable?
The price and inventory of SMAJ18C-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 SMAJ18C-E3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ18C-E3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18C-E3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18C-E3/5A?
SMAJ18C-E3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18C-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 SMAJ18C-E3/5A?
For technical support, including SMAJ18C-E3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18C-E3/5A requirements.
6.How does Aetrix verify that SMAJ18C-E3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ18C-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 SMAJ18C-E3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ18C-E3/5A?
All SMAJ18C-E3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18C-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 SMAJ18C-E3/5A part is unused and in its original packaging.
Return procedure for SMAJ18C-E3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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