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Vishay General Semiconductor - Diodes Division SMAJ18CA-M3/5A
- Part No.:
- SMAJ18CA-M3/5A
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18CA-M3/5A.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:3,912
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Product details
Overview
SMAJ18CA-M3/5A from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal and power lines. It features a 18 V standoff voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 29.2 V maximum clamping voltage (VC) at 13.7 A peak pulse current (IPPM), and 400 W peak pulse power (10/1000 μs waveform), used to protect MOSFETs, ICs, and sensor interfaces in automotive and industrial systems.
For engineers reviewing the SMAJ18CA-M3/5A datasheet, SMAJ18CA-M3/5A pinout, SMAJ18CA-M3/5A application, or SMAJ18CA-M3/5A equivalent, key selection criteria include bidirectional clamping capability, 150 °C max junction temperature, halogen-free RoHS-compliant construction (M3 suffix), low incremental surge resistance, and compatibility with automated SMT placement on standard PCB copper pads.
Technical Context
This TVS diode operates as a voltage-clamped shunt protector: under normal conditions it presents high impedance (>1 μA leakage at 18 V), but triggers into low-impedance conduction when reverse voltage exceeds its 20.0–22.1 V breakdown range. Its 10/1000 μs waveform response delivers 29.2 V clamping at 13.7 A, enabling robust protection against ESD, lightning-induced surges, and inductive switching spikes.
The device uses a glass-passivated silicon junction housed in an SMA (DO-214AC) package with matte tin-plated leads, rated for MSL Level 1 per J-STD-020 and qualified to AEC-Q101 when ordered with HE3/HM3 suffixes. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), supporting operation from –55 °C to +150 °C.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM (Stand-off Voltage) | 18 V - Maximum continuous reverse operating voltage before significant leakage begins; defines safe operating margin below clamping threshold. |
| VBR (Breakdown Voltage) | 20.0–22.1 V at 1 mA - Confirmed voltage range where device transitions from high- to low-impedance state; ensures predictable turn-on behavior. |
| VC (Clamping Voltage) | 29.2 V at IPPM = 13.7 A - Peak voltage seen by protected circuit during 10/1000 μs surge; directly limits stress on downstream components. |
| PPPM (Peak Pulse Power) | 400 W (10/1000 μs) - Surge energy handling capacity on 0.2" × 0.2" copper pads; supports repetitive 0.01% duty cycle events. |
| ID (Reverse Leakage) | 1.0 μA at 18 V - Low leakage preserves signal integrity and minimizes standby power loss in always-on circuits. |
| TJ max. | +150 °C - Enables reliable operation in under-hood automotive and high-temperature industrial environments. |
| Package | SMA (DO-214AC) - Surface-mount footprint compatible with standard reflow profiles; meets UL 94 V-0 flammability rating. |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking. Terminals are matte tin-plated leads, solderable per J-STD-002 and JESD 22-B102.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode | Current entry terminal in forward bias; common node for bidirectional clamping path | Connected to line being protected; forms symmetrical clamping path with cathode during either polarity surge. |
| Cathode | Current exit terminal in forward bias; common node for bidirectional clamping path | Connected to line being protected; enables identical clamping behavior for positive and negative transients. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity concerns. |
| 400 W peak pulse power (10/1000 μs) | Handles high-energy transients from inductive load switching and ESD events in compact SMA footprint. |
| Halogen-free, RoHS-compliant (M3 suffix) | Meets environmental compliance requirements for automotive and industrial end equipment without compromising surge performance. |
| MSL Level 1 moisture sensitivity | Allows unlimited floor life and standard reflow processing without baking or special handling. |
| Low clamping ratio (VC/VBR ≈ 1.39) | Minimizes overvoltage exposure to protected ICs by tightly constraining clamped voltage relative to breakdown. |
Applications
| Automotive Sensor Interface Protection | Industrial CAN Bus Line Protection |
|---|---|
|
Use Scenario: Protecting analog sensor outputs (e.g., pressure, temperature) connected to microcontrollers in engine control units against load dump and alternator ripple. IC Role / Device Role / Timing Role: Bidirectional shunt clamp absorbing ±200 V transients while maintaining <1 μA leakage at 18 V system rail. Use Value: Prevents sensor signal corruption and MCU reset events without adding series impedance or propagation delay. |
Use Scenario: Safeguarding CANH/CANL differential pair in factory automation nodes exposed to motor drive noise and ground bounce. IC Role / Device Role / Timing Role: Symmetric clamping device placed across differential lines to limit common-mode surges to <30 V peak. Use Value: Maintains CAN signal integrity up to 1 Mbps by avoiding capacitive loading >100 pF and preserving differential timing margins. |
| Consumer USB Port ESD Protection | Telecom Power Supply Input Clamping |
|
Use Scenario: Shielding USB 2.0 D+/D− lines in portable devices from IEC 61000-4-2 contact discharge (±8 kV). IC Role / Device Role / Timing Role: Low-capacitance bidirectional TVS placed adjacent to connector to divert ESD current before reaching PHY IC. Use Value: Achieves sub-100 ps response time and clamps transients to <30 V, preventing latch-up in USB transceivers. |
Use Scenario: Suppressing 100 V/1 ms surges on 24 V DC input rails of telecom base station power modules. IC Role / Device Role / Timing Role: Primary-stage shunt protector upstream of DC/DC converters, rated for 400 W non-repetitive pulses. Use Value: Absorbs surge energy without fuse blowing or thermal runaway, enabling single-stage protection architecture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-M3/5A | Unidirectional; same VWM (18 V), VBR (20.0–22.1 V), VC (29.2 V), and package; cathode band marking required. | Requires correct polarity orientation; unsuitable for AC or floating lines without external biasing. | Select when protecting DC rails with known polarity and space-constrained layouts favoring unidirectional optimization. |
| SMBJ18CA-M3/5A | Same electrical specs but SMB (DO-214AA) package; 2.54 mm lead pitch vs. SMA's 2.29 mm; 600 W PPPM rating. | Larger footprint; higher surge rating enables longer-life protection in high-cycle industrial environments. | Choose when board layout allows larger pad area and system-level surge testing requires >400 W margin. |
Compared with SMAJ18CA-M3/5A, the unidirectional SMAJ18A-M3/5A demands strict polarity alignment but offers identical clamping performance, while the SMBJ18CA-M3/5A trades compactness for 50 % higher surge power handling in a physically larger package.
Availability
SMAJ18CA-M3/5A 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 and halogen-free compliance.
Supply support for SMAJ18CA-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, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.
The SMAJ series was developed for high-reliability transient suppression in automotive, industrial, and telecom systems where compact size, bidirectional capability, and AEC-Q101 qualification are critical design requirements.
FAQ
What is the clamping voltage of SMAJ18CA-M3/5A at its rated peak pulse current?
The SMAJ18CA-M3/5A has a maximum clamping voltage (VC) of 29.2 V at its peak pulse current (IPPM) of 13.7 A, measured under the standard 10/1000 μs waveform condition. This value ensures protected circuits experience minimal overvoltage during surge events. The SMAJ18CA-M3/5A maintains this clamping performance across its full operating temperature range of –55 °C to +150 °C.
Is SMAJ18CA-M3/5A suitable for automotive applications?
Yes, SMAJ18CA-M3/5A is halogen-free and RoHS-compliant (M3 suffix), and the base SMAJ18CA family is AEC-Q101 qualified when ordered with HE3 or HM3 suffixes. While SMAJ18CA-M3/5A itself is commercial-grade, its electrical specs-including 150 °C max junction temperature and robust 400 W surge rating-align with automotive subsystem requirements such as body control modules and sensor interfaces.
How does the bidirectional design of SMAJ18CA-M3/5A affect its circuit implementation?
The bidirectional design of SMAJ18CA-M3/5A eliminates polarity marking and allows placement across any two-node interface regardless of DC bias direction-ideal for AC-coupled lines, differential buses like CAN or RS-485, or floating sensors. Unlike unidirectional variants, SMAJ18CA-M3/5A provides symmetrical clamping for both positive- and negative-going transients without external biasing or additional components.
What is the thermal resistance of SMAJ18CA-M3/5A, and how does it impact PCB layout?
SMAJ18CA-M3/5A has a typical junction-to-ambient thermal resistance (RθJA) of 120 °C/W and junction-to-lead resistance (RθJL) of 30 °C/W when mounted on minimum recommended 0.2" × 0.2" copper pads. To maintain reliability under repetitive surges, designers must allocate adequate copper area per terminal and avoid excessive trace length between the SMAJ18CA-M3/5A and ground/power planes.
Does SMAJ18CA-M3/5A meet moisture sensitivity level (MSL) requirements for standard SMT assembly?
Yes, SMAJ18CA-M3/5A meets MSL Level 1 per J-STD-020, meaning it has unlimited floor life and can undergo standard reflow soldering profiles-including peak temperatures up to 260 °C-without preconditioning or dry-pack requirements. This simplifies manufacturing logistics and reduces risk of popcorning or delamination during assembly.
SMAJ18CA-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:
- -
- 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:
- General Purpose
- Capacitance @ Frequency:
- -
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- DO-214AC (SMA)
SMAJ18CA-M3/5A FAQ
1.How can I place an order for SMAJ18CA-M3/5A through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18CA-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 SMAJ18CA-M3/5A reliable?
The price and inventory of SMAJ18CA-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 SMAJ18CA-M3/5A is usually 5 days.
3.What payment methods are accepted for SMAJ18CA-M3/5A?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18CA-M3/5A transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18CA-M3/5A?
SMAJ18CA-M3/5A orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18CA-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 SMAJ18CA-M3/5A?
For technical support, including SMAJ18CA-M3/5A datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18CA-M3/5A requirements.
6.How does Aetrix verify that SMAJ18CA-M3/5A is sourced from the original manufacturer or authorized distributors?
All SMAJ18CA-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 SMAJ18CA-M3/5A meets industry standards.
7.What is the process for return or replacement of SMAJ18CA-M3/5A?
All SMAJ18CA-M3/5A units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18CA-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 SMAJ18CA-M3/5A part is unused and in its original packaging.
Return procedure for SMAJ18CA-M3/5A:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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