Vishay General Semiconductor - Diodes Division SM6T30A-M3/5B

Overview

SM6T30A-M3/5B from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, rated for 30 V breakdown voltage (V_BR = 28.5–31.5 V at 1.0 mA), 41.5 V maximum clamping voltage (V_C) at 14.5 A peak pulse current, and 600 W peak pulse power with 10/1000 μs waveform. It protects MOSFETs and ICs against inductive switching transients in automotive power electronics.

For engineers reviewing the SM6T30A-M3/5B datasheet, SM6T30A-M3/5B pinout, SM6T30A-M3/5B application, or SM6T30A-M3/5B equivalent, key selection criteria include unidirectional polarity, 25.6 V stand-off voltage (V_WM), 1.0 μA max reverse leakage at V_WM, 150 °C max junction temperature, and halogen-free RoHS-compliant construction per M3 suffix.

Technical Context

This TVS diode operates as a clamping device in parallel with sensitive circuit nodes, conducting only when transient voltage exceeds its breakdown threshold. Its glass-passivated junction ensures stable V_BR tolerance (±5%) and low dynamic impedance under surge conditions.

Designed for surface-mount assembly on standard PCB pads (0.2" × 0.2"), it delivers low-inductance transient response and meets J-STD-020 MSL Level 1 with 260 °C reflow peak. The cathode band identifies polarity; no marking is used for bidirectional variants.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, matte tin-plated leads solderable per J-STD-002. Cathode identified by molded band.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ30A and SMCJ30A, the SM6T30A-M3/5B delivers certified 600 W surge capacity in the smallest viable package for automotive-grade reliability-making it the preferred choice where board space, thermal performance, and AEC-Q101 alignment (via HM3 variant) are jointly critical.

Availability

SM6T30A-M3/5B is available at Aetrix Electronics and suitable for automotive electronics, industrial motor drives, consumer power adapters, and telecom DC interfaces requiring stable component supply and halogen-free compliance.

Supply support for SM6T30A-M3/5B 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, TVS devices, and optoelectronics with emphasis on reliability and automotive qualification.

The SM6T Series is engineered for high-energy transient suppression in harsh environments, targeting automotive, industrial, and telecom applications where consistent clamping performance and AEC-Q101 readiness are essential.

FAQ

What is the breakdown voltage tolerance of the SM6T30A-M3/5B?

The SM6T30A-M3/5B has a specified breakdown voltage (V_BR) range of 28.5 V to 31.5 V at 1.0 mA test current, representing a ±5% tolerance around the nominal 30 V rating. This tight tolerance ensures predictable clamping behavior across production lots and temperature ranges, critical for protecting 3.3 V or 5 V logic interfaces referenced to higher rails. The SM6T30A-M3/5B maintains this specification per Vishay Document Number 88385, Revision 09-Jan-2024.

Is the SM6T30A-M3/5B suitable for automotive applications?

Yes, the SM6T30A-M3/5B is halogen-free and RoHS-compliant per its M3 suffix, and the SM6T family offers AEC-Q101 qualified variants (HM3 suffix). While the SM6T30A-M3/5B itself is commercial-grade, its electrical specs-including 150 °C max junction temperature, 600 W surge rating, and glass-passivated junction-align with automotive environmental stress requirements. Designers commonly use it in non-safety-critical automotive subsystems such as infotainment power inputs or sensor interface protection. The SM6T30A-M3/5B meets J-STD-020 MSL Level 1 for lead-free reflow.

What is the maximum clamping voltage of the SM6T30A-M3/5B under surge conditions?

The SM6T30A-M3/5B has a maximum clamping voltage (V_C) of 41.5 V at 14.5 A peak pulse current using the industry-standard 10/1000 μs double-exponential waveform. This value is measured under defined test conditions (mounted on 0.2" × 0.2" copper pads) and represents the upper limit of voltage imposed on protected circuitry during worst-case transient events. The SM6T30A-M3/5B achieves this with low dynamic impedance, ensuring effective energy diversion without overstressing downstream components.

How does the SM6T30A-M3/5B differ from bidirectional TVS diodes like SM6T30CA?

The SM6T30A-M3/5B is unidirectional and features a cathode band for polarity identification, enabling asymmetric protection-clamping only in reverse bias while conducting forward like a rectifier. In contrast, SM6T30CA is bidirectional, offering symmetrical clamping in both directions with no polarity marking. The SM6T30A-M3/5B is selected for DC power line protection (e.g., 12 V battery rails), whereas SM6T30CA suits AC signal lines or differential buses. Both share identical V_BR, V_C, and P_PPM, but their circuit integration differs fundamentally.

What is the thermal resistance of the SM6T30A-M3/5B, and how does it affect PCB layout?

The SM6T30A-M3/5B has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on minimum recommended 0.2" × 0.2" copper pads per terminal. This value assumes standard FR-4 PCB with no internal planes; adding thermal vias or larger copper areas reduces R_θJA significantly. For continuous power dissipation near its 5.0 W rating, designers must ensure adequate copper area and airflow. The SM6T30A-M3/5B's R_θJL of 20 °C/W indicates efficient heat transfer to leads, supporting reliable operation in thermally constrained automotive modules.