Vishay General Semiconductor - Diodes Division SMC3K33CA-M3/57

Overview

SMC3K33CA-M3/57 from Vishay General Semiconductor is a bidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMC (DO-214AB) package, rated for 3000 W peak pulse power (10/1000 μs), with breakdown voltage 36.7–40.6 V, stand-off voltage 33 V, and clamping voltage 53.3 V at 56.3 A peak surge current. It protects MOSFETs, ICs, and sensor signal lines against inductive switching transients and lightning surges in automotive and industrial systems.

For engineers reviewing the SMC3K33CA-M3/57 datasheet, SMC3K33CA-M3/57 pinout, SMC3K33CA-M3/57 application, or SMC3K33CA-M3/57 equivalent, key selection criteria include bidirectional clamping capability, AEC-Q101 qualification, MSL Level 1 moisture sensitivity, 150 °C max junction temperature, and compatibility with wave soldering limitations on PCB bottom side.

Technical Context

This TVS diode operates as a voltage-clamped crowbar device during transient overvoltage events, leveraging avalanche breakdown to divert surge current away from protected circuitry. Its low incremental surge resistance and fast response time ensure effective suppression of sub-microsecond transients induced by inductive load switching or ESD.

The device is specified for bidirectional polarity only, with no marking on the case, and meets UL 497B safety recognition (E136766). It is halogen-free, RoHS-compliant, and qualified per JESD 201 Class 2 whisker test - critical for long-term reliability in automotive and industrial environments.

Key Specifications

Pinout & Package

SMC3K33CA-M3/57 uses the SMC (DO-214AB) package: molded plastic body with two coplanar matte tin-plated leads, compliant with J-STD-002 and JESD 22-B102 solderability standards. Polarity is bidirectional; no marking on case.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMC3K33CA-M3/57, the HM3 variant adds formal automotive qualification without electrical change, while SMC3K36CA-M3/57 trades lower clamping headroom for higher stand-off tolerance - enabling design flexibility across 24 V and 36 V platforms.

Availability

SMC3K33CA-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 control requiring stable component supply and long-term sourcing continuity.

Supply support for SMC3K33CA-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 engineered specifically for robust transient suppression in harsh environments - targeting automotive, industrial, and telecom applications where 3 kW surge handling and AEC-Q101 compliance are mandatory.

FAQ

What is the maximum clamping voltage of SMC3K33CA-M3/57 at its rated peak pulse current?

The SMC3K33CA-M3/57 has a maximum clamping voltage (V_C) of 53.3 V at 56.3 A peak pulse current (I_PPM) under the standardized 10/1000 μs waveform. This value is measured per ANSI/IEEE C62.35 and ensures predictable voltage limiting during surge events. The SMC3K33CA-M3/57 maintains this clamping performance across its full operating temperature range of −55 °C to +150 °C.

Is SMC3K33CA-M3/57 suitable for automotive applications?

Yes, SMC3K33CA-M3/57 is halogen-free, RoHS-compliant, and meets JESD 201 Class 2 whisker test requirements. While it carries the commercial-grade M3 suffix, its underlying die and construction are identical to the AEC-Q101-qualified SMC3K33CAHM3/57. For non-safety-critical automotive subsystems (e.g., body electronics), the SMC3K33CA-M3/57 is widely deployed - though full AEC-Q101 documentation requires the HM3 variant. The SMC3K33CA-M3/57 itself is not AEC-Q101 certified.

What does the "-M3/57" suffix mean in SMC3K33CA-M3/57?

The "-M3" suffix indicates halogen-free, RoHS-compliant, commercial-grade construction with JESD 201 Class 2 whisker resistance. The "/57" denotes packaging in 7-inch diameter plastic tape and reel, with a base quantity of 850 units per reel. This packaging format is optimized for high-speed SMT placement and is compatible with standard pick-and-place equipment used in electronics manufacturing. The SMC3K33CA-M3/57 ships in this configuration unless otherwise ordered.

Can SMC3K33CA-M3/57 be used in bidirectional signal lines like RS-485 or CAN?

Yes, SMC3K33CA-M3/57 is explicitly designed for bidirectional operation and is commonly applied on differential bus lines including RS-485, CAN, and LIN. Its symmetrical clamping characteristic ensures equal protection for both polarities of transient events without requiring orientation during placement. The SMC3K33CA-M3/57's low leakage (<2 μA at 33 V) avoids signal distortion, and its fast response preserves data integrity during ESD or EFT events.

What is the thermal derating behavior of SMC3K33CA-M3/57 above 25 °C ambient?

The SMC3K33CA-M3/57 follows standard JEDEC derating curves: peak pulse power decreases linearly from 100% at 25 °C to ~50% at 125 °C junction temperature, per Figure 2 in Vishay document 89433. Derating is based on initial junction temperature, not ambient - so PCB layout, copper area, and airflow critically impact real-world performance. The SMC3K33CA-M3/57 must be mounted on ≥8.0 mm × 8.0 mm copper pads to achieve published ratings; smaller pads reduce sustainable surge energy.