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Vishay General Semiconductor - Diodes Division SMAJ18CA-M3/61
- Part No.:
- SMAJ18CA-M3/61
- Manufacturer:
- Vishay General Semiconductor - Diodes Division
- Category:
- TVS Diodes
- Package:
- DO-214AC, SMA
- Datasheet:
-
SMAJ18CA-M3/61.pdf
- Description:
- TVS DIODE 18VWM 29.2VC DO214AC
- Quantity:
- Payment:
- Shipping:
Inventory:5,107
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Product details
Overview
SMAJ18CA-M3/61 from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMA (DO-214AC) package, designed for clamping voltage transients on signal or power lines. It features a 18 V standoff voltage (VWM), 20.0–22.1 V breakdown voltage (VBR) at 1 mA, 400 W peak pulse power (10/1000 μs), and clamps to ≤29.2 V at 13.7 A peak surge current - used to protect MOSFETs, ICs, and sensor signal lines in automotive and industrial control systems.
For engineers reviewing the SMAJ18CA-M3/61 datasheet, SMAJ18CA-M3/61 pinout, SMAJ18CA-M3/61 application, or SMAJ18CA-M3/61 equivalent, key selection criteria include bidirectional clamping capability, 150 °C max junction temperature, halogen-free RoHS-compliant construction (M3 suffix), and compatibility with automated SMT placement on PCBs with standard 0.2" × 0.2" copper pads.
Technical Context
This TVS diode operates as a voltage-clamping protection device across two terminals, responding within <1 ps to transient overvoltages induced by inductive switching or ESD events. Its bidirectional symmetry ensures identical clamping behavior in both polarities, eliminating polarity concerns during board layout.
The device uses a glass-passivated silicon junction with low incremental surge resistance (typical Rdyn ≈ 1.2 Ω), enabling stable clamping under repetitive 0.01% duty-cycle surges. Thermal resistance is 120 °C/W (junction-to-ambient) and 30 °C/W (junction-to-lead), supporting operation up to 150 °C junction temperature with appropriate PCB copper area.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VWM | 18 V - maximum continuous reverse operating voltage before significant leakage; defines safe operating margin below clamping threshold |
| VBR (min/max) | 20.0 V / 22.1 V at 1 mA - verified breakdown range ensuring reliable turn-on during transients without premature conduction |
| VC @ IPPM | ≤29.2 V at 13.7 A - clamped voltage level that determines maximum stress imposed on protected downstream circuitry |
| PPPM | 400 W (10/1000 μs waveform) - peak transient energy absorption capacity; derates to 300 W above 78 V |
| IFSM | 40 A (8.3 ms half-sine) - surge current rating for unidirectional devices; not applicable to bidirectional SMAJ18CA but confirms robust junction design |
| TJ max | +150 °C - maximum junction temperature enabling use in under-hood automotive and high-temperature industrial environments |
| Package | SMA (DO-214AC) - standardized surface-mount outline with 0.208" length, 0.157" width, and 0.090" height; compatible with JEDEC MS-013 |
Pinout & Package
Package: SMA (DO-214AC), surface-mount, bidirectional configuration with no polarity marking - both terminals are electrically symmetric and interchangeable.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| Anode/Cathode (bidirectional) | Transient current path | Both terminals serve as symmetrical surge conduction paths; no cathode band marking required per bidirectional design |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional clamping | Enables single-device protection of AC-coupled or floating signal lines without polarity constraints |
| 400 W peak pulse power (10/1000 μs) | Supports robust immunity against ISO 7637-2 Pulse 1/2a/5a and IEC 61000-4-5 Level 3 surges |
| Halogen-free, RoHS-compliant (M3 suffix) | Fulfills environmental compliance requirements for automotive and industrial end equipment without compromising thermal performance |
| MSL Level 1 (J-STD-020), 260 °C reflow peak | Enables direct placement into standard lead-free SMT reflow profiles without pre-baking |
| Low incremental surge resistance (~1.2 Ω) | Minimizes voltage overshoot during fast-rising transients, improving protection margin for sensitive CMOS inputs |
Applications
| Automotive Power Line Protection | Industrial Sensor Interface Protection |
|---|---|
Use Scenario: Protecting 12 V battery-fed ECUs from load dump and alternator ripple transients. IC Role / Device Role / Timing Role: Bidirectional voltage clamp placed across power rail input prior to DC/DC converter. Use Value: Limits transient excursions to ≤29.2 V, preventing damage to 36 V-rated input stages while surviving 400 W pulses. |
Use Scenario: Shielding analog output lines (e.g., 4–20 mA current loop) from ESD and field wiring surges. IC Role / Device Role / Timing Role: Low-capacitance TVS connected between signal line and ground, adjacent to connector. Use Value: Clamps sub-100 ns ESD events without distorting low-bandwidth analog signals due to minimal dynamic impedance. |
| Consumer USB Port Surge Suppression | Telecom Data Line Transient Protection |
Use Scenario: Safeguarding USB 2.0 D+/D− lines in portable chargers and docking stations against contact ESD. IC Role / Device Role / Timing Role: Bidirectional TVS pair placed differentially across data lines, referenced to ground. Use Value: Maintains signal integrity with <10 pF junction capacitance at VWM, while clamping ±15 kV HBM ESD to <30 V. |
Use Scenario: Protecting RS-485 transceiver I/O pins in base station backhaul equipment exposed to lightning-induced surges. IC Role / Device Role / Timing Role: Line-to-ground TVS on each differential pair, mounted at entry connector. Use Value: Absorbs 10/1000 μs surges up to 400 W without latch-up, preserving communication uptime in outdoor deployments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar transient voltage suppression applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMAJ18A-M3/61 | Unidirectional; cathode band marked; same VWM, VBR, and PPPM; forward conduction capability | Required where DC bias exists and polarity is fixed (e.g., +12 V supply rail only) | Select when protecting unidirectional power rails with known polarity and need for forward surge handling |
| SMBJ18CA-M3/61 | Same electrical specs but SMB (DO-214AA) package - 20 % larger footprint, 10 % higher PPPM (600 W), lower RθJA (90 °C/W) | Better thermal performance for high-repetition-rate surges; requires larger PCB pad area | Choose when enhanced thermal margin or higher surge repetition tolerance is needed and board space permits SMB outline |
Compared with SMAJ18CA-M3/61, the unidirectional SMAJ18A-M3/61 adds forward conduction capability but requires polarity-aware layout, while SMBJ18CA-M3/61 offers superior thermal dissipation and surge headroom at the cost of increased board area - making SMAJ18CA-M3/61 optimal for space-constrained bidirectional protection.
Availability
SMAJ18CA-M3/61 is available at Aetrix Electronics and suitable for automotive body control modules, industrial PLC analog I/O cards, and telecom remote terminal units requiring stable component supply with halogen-free compliance and AEC-Q101 qualification readiness.
Supply support for SMAJ18CA-M3/61 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 SMAJ series is engineered for robust transient suppression in harsh environments - targeting automotive, industrial, and communications systems where compact size, high surge capability, and long-term stability are critical.
FAQ
What does the "CA" suffix indicate in SMAJ18CA-M3/61?
The "CA" suffix in SMAJ18CA-M3/61 denotes a bidirectional Transient Voltage Suppressor. Unlike unidirectional variants (e.g., SMAJ18A), SMAJ18CA-M3/61 provides symmetrical clamping in both voltage polarities - essential for protecting AC-coupled, floating, or polarity-agnostic signal lines without requiring orientation during placement. This eliminates risk of incorrect installation in automated assembly.
Is SMAJ18CA-M3/61 qualified to AEC-Q101?
SMAJ18CA-M3/61 is halogen-free and RoHS-compliant (per M3 suffix), but it is not AEC-Q101 qualified. For automotive-grade qualification, Vishay offers the SMAJ18CAHM3_X variant (e.g., SMAJ18CAHM3_A), which carries the HM3 suffix and explicit AEC-Q101 certification. SMAJ18CA-M3/61 remains suitable for industrial and commercial applications where AEC-Q101 is not mandated.
What is the maximum clamping voltage for SMAJ18CA-M3/61 at its rated peak pulse current?
The maximum clamping voltage (VC) for SMAJ18CA-M3/61 is 29.2 V at 13.7 A peak pulse current (IPPM), measured using the standard 10/1000 μs double-exponential waveform. This value represents the upper limit of voltage seen by protected circuitry during a full-rated surge event and is guaranteed across the operating temperature range of –55 °C to +150 °C.
Can SMAJ18CA-M3/61 be used in place of SMAJ18A-M3/61?
No - SMAJ18CA-M3/61 and SMAJ18A-M3/61 are not interchangeable without circuit review. SMAJ18A-M3/61 is unidirectional with a cathode band and supports forward conduction, while SMAJ18CA-M3/61 is bidirectional with no polarity marking. Substituting one for the other may cause failure in DC-biased circuits or misclamping in AC applications. Always verify polarity requirements and conduction mode before replacement.
What PCB pad layout is recommended for optimal thermal and surge performance of SMAJ18CA-M3/61?
Vishay specifies a minimum 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pad for each terminal of SMAJ18CA-M3/61 to achieve rated 400 W peak pulse power. Larger copper areas improve thermal dissipation and surge repetition capability. The SMA (DO-214AC) package requires solder mask-defined pads aligned to JEDEC MS-013 standards, with no thermal relief on inner layers to maximize heat spreading.
SMAJ18CA-M3/61 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-M3/61 FAQ
1.How can I place an order for SMAJ18CA-M3/61 through Aetrix?
Please submit a Request for Quotation (RFQ) for SMAJ18CA-M3/61 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-M3/61 reliable?
The price and inventory of SMAJ18CA-M3/61 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SMAJ18CA-M3/61 is usually 5 days.
3.What payment methods are accepted for SMAJ18CA-M3/61?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SMAJ18CA-M3/61 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SMAJ18CA-M3/61?
SMAJ18CA-M3/61 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SMAJ18CA-M3/61 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-M3/61?
For technical support, including SMAJ18CA-M3/61 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SMAJ18CA-M3/61 requirements.
6.How does Aetrix verify that SMAJ18CA-M3/61 is sourced from the original manufacturer or authorized distributors?
All SMAJ18CA-M3/61 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-M3/61 meets industry standards.
7.What is the process for return or replacement of SMAJ18CA-M3/61?
All SMAJ18CA-M3/61 units undergo pre-shipment inspection (PSI). If there is an issue with SMAJ18CA-M3/61, 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-M3/61 part is unused and in its original packaging.
Return procedure for SMAJ18CA-M3/61:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SMAJ18CA-M3/61 Tags
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