Vishay General Semiconductor - Diodes Division SM6T15A-M3/5B

Overview

SM6T15A-M3/5B from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, with 12.8 V stand-off voltage (V_WM), 14.3–15.8 V breakdown voltage (V_BR at 1.0 mA), and 21.2 V maximum clamping voltage (V_C) at 28.0 A peak pulse current (I_PPM). It delivers 600 W peak pulse power (10/1000 μs), operates from −65 °C to +150 °C, and protects MOSFETs and ICs against inductive switching transients in automotive power supplies.

For engineers reviewing the SM6T15A-M3/5B datasheet, SM6T15A-M3/5B pinout, SM6T15A-M3/5B application, or SM6T15A-M3/5B equivalent, key selection criteria include clamping voltage margin relative to protected device's absolute maximum rating, I_PPM derating above 25 °C, thermal resistance (R_θJA = 100 °C/W), unidirectional polarity marking, and halogen-free RoHS-compliant M3 suffix qualification.

Technical Context

The SM6T15A-M3/5B employs a glass-passivated silicon junction optimized for fast response (<1 ns) to transient overvoltages. Its unidirectional configuration provides forward conduction path only during reverse overvoltage events, with cathode band marking for polarity identification.

Designed for PCB-level surge protection per IEC 61000-4-5 (8/20 μs waveform), it achieves 27.2 V clamping at 147 A under 8/20 μs stress and exhibits low leakage (<1.0 μA at V_WM) and low inductance due to SMB package geometry and internal leadframe design.

Key Specifications

Pinout & Package

Package: SMB (DO-214AA), surface-mount, halogen-free, RoHS-compliant, MSL Level 1 (260 °C reflow peak). Cathode marked with band on one end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ15A and 1.5SMC15A, the SM6T15A-M3/5B offers optimal balance of compact SMB footprint, 600 W capability, and commercial-grade cost-ideal for space-constrained consumer and industrial designs where AEC-Q101 is not mandated.

Availability

SM6T15A-M3/5B is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface protection, and consumer power adapter input stage applications requiring stable component supply and halogen-free RoHS compliance.

Supply support for SM6T15A-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, MOSFETs, and protection devices with emphasis on reliability, efficiency, and application-specific optimization.

The SM6T Series was engineered for high-reliability transient suppression in space-constrained surface-mount applications, targeting automotive, industrial, and telecom systems where consistent clamping performance and manufacturability are critical.

FAQ

What is the maximum clamping voltage of the SM6T15A-M3/5B under standard test conditions?

The SM6T15A-M3/5B has a maximum clamping voltage (V_C) of 21.2 V when subjected to a 10/1000 μs waveform at its rated peak pulse current of 28.0 A. This value is measured per JEDEC standards and reflects the actual voltage imposed on the protected circuit during surge events. The SM6T15A-M3/5B maintains this clamping performance across its specified operating temperature range, making it suitable for protecting 15 V-rated components in automotive and industrial environments.

Is the SM6T15A-M3/5B suitable for automotive applications requiring AEC-Q101 qualification?

The SM6T15A-M3/5B itself is a commercial-grade part with halogen-free RoHS compliance (M3 suffix), but it is not AEC-Q101 qualified. For automotive applications requiring AEC-Q101, Vishay offers the SM6T15AHM3_X variant (e.g., SM6T15AHM3_B/I), which uses the same die and SMB package but undergoes additional qualification testing. The SM6T15A-M3/5B may be used in non-safety-critical automotive subsystems where qualification is not mandated, but designers must verify system-level compliance independently.

How does the SMB package of the SM6T15A-M3/5B affect its thermal performance?

The SMB (DO-214AA) package of the SM6T15A-M3/5B has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on 5.0 mm × 5.0 mm copper pads per terminal. This limits continuous power dissipation to 5.0 W at 50 °C ambient, but supports 600 W peak pulses due to short duration. To maintain reliability, PCB layout must adhere to Vishay's recommended pad dimensions and avoid thermal isolation; the SM6T15A-M3/5B's performance is directly dependent on proper copper pour implementation.

What is the meaning of the "M3/5B" suffix in SM6T15A-M3/5B?

The "M3" suffix in SM6T15A-M3/5B indicates halogen-free, RoHS-compliant construction meeting JESD201 Class 2 whisker resistance, while "5B" specifies packaging in 13-inch diameter plastic tape and reel with a base quantity of 3200 units. This ordering code ensures traceable, automated-assembly-ready supply with environmental compliance verified per Vishay's material declarations. The SM6T15A-M3/5B is distinct from E3-suffix (standard RoHS) and HM3-suffix (AEC-Q101 qualified) variants.

Can the SM6T15A-M3/5B be used in bidirectional configurations?

No, the SM6T15A-M3/5B is strictly a unidirectional TVS diode, identified by its cathode band marking. Bidirectional operation requires the CA-suffixed variant (e.g., SM6T15CA), which has symmetrical breakdown in both polarities. Using the SM6T15A-M3/5B in reverse-biased configurations beyond its specified V_WM will cause permanent damage. Designers must select SM6T15CA or equivalent for AC line or differential signal protection where polarity reversal occurs.