Vishay General Semiconductor - Diodes Division SMCJ30CAHE3_A/H

Overview

SMCJ30CAHE3_A/H from Vishay General Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in SMC (DO-214AB) package, designed for robust overvoltage protection of sensitive electronics. It features a 30 V standoff voltage (V_WM), 48.4 V maximum clamping voltage (V_C) at 31.0 A peak pulse current (I_PPM), and 1500 W peak pulse power (10/1000 µs waveform), making it suitable for automotive power line and industrial sensor interface protection.

For engineers reviewing the SMCJ30CAHE3_A/H datasheet, SMCJ30CAHE3_A/H pinout, SMCJ30CAHE3_A/H application, or SMCJ30CAHE3_A/H equivalent, key selection considerations include bidirectional surge capability, AEC-Q101 qualification, low clamping ratio (V_C/V_WM = 1.61), RoHS-compliant matte tin terminations, and compatibility with automated SMT placement on standard PCB pad layouts.

Technical Context

This device operates as a voltage-clamped crowbar during transients, leveraging an avalanche breakdown mechanism to divert surge energy away from downstream circuitry. Its bidirectional symmetry ensures identical clamping behavior in both polarities, eliminating polarity marking requirements and simplifying layout in AC-coupled or floating signal paths.

Thermally, it exhibits R_θJA = 75 °C/W (typ.) and R_θJL = 15 °C/W (typ.), enabling reliable operation up to T_J = +150 °C. The glass-passivated junction and MSL Level 1 rating support reflow soldering at peak temperatures up to 260 °C without degradation.

Key Specifications

Pinout & Package

Package: SMC (DO-214AB), surface-mount, low-profile case with matte tin-plated leads compliant with J-STD-002 and JESD 22-B102. No polarity marking - bidirectional construction eliminates cathode/anode distinction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SAC30CA, SMCJ30CAHE3_A/H delivers 2.5× higher surge power handling and automotive qualification; compared with SMCJ30CAHM3_A/H, it shares full functional equivalence except for halogen content-making HE3 the default choice unless halogen-free certification is mandatory.

Availability

SMCJ30CAHE3_A/H is available at Aetrix Electronics and suitable for automotive electronic control units, industrial sensor interfaces, telecom infrastructure equipment, and consumer USB protection requiring stable component supply and AEC-Q101 assurance.

Supply support for SMCJ30CAHE3_A/H 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 high-reliability diodes, rectifiers, and protection devices for demanding industrial and automotive applications.

The SMCJ series was engineered specifically for high-power transient suppression in harsh environments, emphasizing low clamping voltage, repeatable avalanche performance, and extended thermal survivability beyond standard TVS offerings.

FAQ

What is the clamping voltage of the SMCJ30CAHE3_A/H at its rated peak pulse current?

The SMCJ30CAHE3_A/H has a maximum clamping voltage (V_C) of 48.4 V when subjected to its rated peak pulse current of 31.0 A using the standardized 10/1000 µs waveform. This value is measured under defined test conditions per ANSI/IEEE C62.35 and represents the upper bound of voltage seen by protected circuitry during worst-case surge events. The SMCJ30CAHE3_A/H maintains this clamping performance across its qualified operating temperature range.

Is the SMCJ30CAHE3_A/H suitable for automotive applications?

Yes, the SMCJ30CAHE3_A/H is AEC-Q101 qualified and explicitly designed for automotive use, including engine control modules, body electronics, and infotainment systems. Its qualification covers high-temperature operation up to +150 °C, resistance to thermal cycling, and robustness against mechanical shock and vibration. The SMCJ30CAHE3_A/H meets ISO 16750-2 load dump and ISO 7637-2 pulse immunity requirements when applied with appropriate layout and filtering.

How does the bidirectional design of the SMCJ30CAHE3_A/H affect PCB layout?

The bidirectional nature of the SMCJ30CAHE3_A/H eliminates polarity marking and allows symmetrical placement across any two-node interface-such as differential data lines, AC power inputs, or floating sensor outputs-without regard to signal direction. Unlike unidirectional TVS diodes, the SMCJ30CAHE3_A/H requires no orientation check during automated placement, reducing assembly errors and enabling simplified routing with equal trace lengths to both terminals.

What is the thermal resistance of the SMCJ30CAHE3_A/H, and how does it impact power dissipation?

The SMCJ30CAHE3_A/H has a typical junction-to-ambient thermal resistance (R_θJA) of 75 °C/W and junction-to-lead resistance (R_θJL) of 15 °C/W. These values define its ability to dissipate heat during repetitive or sustained surge events. At ambient temperatures above 25 °C, derating applies per Figure 2 in the datasheet; for example, at 85 °C ambient, the maximum allowable average power drops to ~3.5 W. Proper copper pad sizing (0.31" x 0.31") is essential to achieve the published R_θJA.

Does the SMCJ30CAHE3_A/H require external components to function effectively in surge protection circuits?

The SMCJ30CAHE3_A/H functions as a standalone shunt protector and does not require external components to clamp transients. However, optimal system-level protection typically includes series impedance (e.g., ferrite bead or resistor) upstream to limit di/dt and coordinate with upstream protectors like GDTs or MOVs. For the SMCJ30CAHE3_A/H, such coordination ensures energy sharing and prevents premature failure during multi-stage surge events like lightning-induced surges per IEC 61000-4-5.