Vishay General Semiconductor - Diodes Division SMC3K26CA-M3/57

Overview

SMC3K26CA-M3/57 from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) in SMC (DO-214AB) package, designed for high-energy surge protection with 3000 W peak pulse power (10/1000 μs), 28.9–31.9 V breakdown voltage, and 42.1 V maximum clamping voltage at 71.3 A peak pulse current. It protects MOSFETs, ICs, and sensor signal lines in automotive and industrial power electronics.

For engineers reviewing the SMC3K26CA-M3/57 datasheet, SMC3K26CA-M3/57 pinout, SMC3K26CA-M3/57 application, or SMC3K26CA-M3/57 equivalent, key selection criteria include bidirectional polarity, AEC-Q101 qualification, 150 °C max junction temperature, M3 halogen-free RoHS-compliant construction, and compatibility with wave-soldering restrictions on PCB bottom side.

Technical Context

This TVS diode operates as a voltage-clamping device triggered by transient overvoltage events, using avalanche breakdown to shunt surge current away from protected circuitry. Its low incremental surge resistance and fast response time ensure effective suppression of inductive switching spikes and lightning-induced transients.

The device is rated for non-repetitive 10/1000 μs waveform surges up to 3000 W, with thermal derating above 25 °C ambient and full operation across –55 °C to +150 °C junction temperature range. It meets J-STD-020 MSL Level 1 and UL 497B safety recognition (E136766).

Key Specifications

Pinout & Package

SMC3K26CA-M3/57 uses a 2-terminal SMC (DO-214AB) package with no polarity marking for bidirectional operation. Terminals are matte tin-plated leads, solderable per J-STD-002 and JESD 22-B102, and meet JESD 201 Class 2 whisker test requirements.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar transient voltage suppression applications.

Compared with SMC3K26CA-M3/57, SMC3K26CAHM3/57 adds automotive qualification without electrical or mechanical change, while SMC3K24CA-M3/57 trades 2 V lower stand-off for 3.2 V lower clamping - making it viable only in 24 V systems where tighter voltage control outweighs reduced surge tolerance.

Availability

SMC3K26CA-M3/57 is available at Aetrix Electronics and suitable for automotive power distribution, industrial sensor interface protection, telecom line card surge protection, and consumer appliance motor drive protection requiring stable component supply and legacy design support.

Supply support for SMC3K26CA-M3/57 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 high-reliability, high-power, and automotive-grade performance.

The SMC3KxxCA series was developed for high-energy transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where robustness, consistency, and safety certification are critical.

FAQ

What does the "-M3/57" suffix mean in SMC3K26CA-M3/57?

The "-M3" suffix indicates halogen-free, RoHS-compliant, commercial-grade construction meeting JESD 201 Class 2 whisker resistance, while "/57" specifies packaging in 7-inch diameter plastic tape and reel containing 850 units. This configuration ensures compatibility with standard SMT pick-and-place equipment and satisfies environmental compliance requirements for industrial and consumer applications. The SMC3K26CA-M3/57 is not AEC-Q101 qualified - that designation requires the HM3 suffix.

Is SMC3K26CA-M3/57 suitable for new automotive designs?

No - Vishay explicitly marks SMC3K26CA-M3/57 as "Not for New Designs" in its datasheet, recommending SMC3K26CAHM3_A instead. The SMC3K26CA-M3/57 lacks AEC-Q101 qualification required for modern automotive programs, though it remains viable for legacy repair, industrial retrofits, or non-automotive applications where commercial-grade reliability suffices. For new automotive projects, specify SMC3K26CAHM3/57 or SMC3K26CAHM3_A.

What is the maximum clamping voltage of SMC3K26CA-M3/57 and how is it measured?

The maximum clamping voltage of SMC3K26CA-M3/57 is 42.1 V, measured at 71.3 A peak pulse current using a standardized 10/1000 μs double-exponential surge waveform. This value represents the upper limit of voltage imposed on protected circuitry during worst-case transient events and is guaranteed across the full operating temperature range. The SMC3K26CA-M3/57 achieves this with low incremental surge resistance, ensuring predictable, repeatable protection behavior in real-world surge conditions.

Can SMC3K26CA-M3/57 be used in bidirectional signal lines like RS-485 or CAN?

Yes - SMC3K26CA-M3/57 is inherently bidirectional and has no polarity marking, making it ideal for protecting differential or AC-coupled signal lines such as RS-485, CAN, or LVDS. It clamps symmetrically on both polarities, limiting voltage excursions to ≤42.1 V regardless of surge direction. Its low capacitance (<100 pF at zero bias) minimizes signal distortion, and its fast response ensures protection before transceiver ICs experience latch-up or permanent damage.

What is the thermal derating behavior of SMC3K26CA-M3/57 above 25 °C ambient?

SMC3K26CA-M3/57 follows linear thermal derating above 25 °C ambient: peak pulse power decreases proportionally as junction temperature rises, reaching zero at 150 °C. Derating curves in the datasheet show ~75 % power capability at 75 °C ambient and ~50 % at 100 °C, assuming proper PCB copper area (0.31″ × 0.31″) per the recommended pad layout. This behavior ensures safe operation in high-temperature enclosures or under-hood automotive locations when thermal design accounts for the specified derating slope.