Vishay General Semiconductor - Diodes Division P6SMB6.8A-M3/5B

Overview

P6SMB6.8A-M3/5B from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode in SMB (DO-214AA) package, with 6.45 V minimum and 7.14 V maximum breakdown voltage at 10 mA test current, 5.80 V standoff voltage, 1000 μA max reverse leakage at VWM, and 10.5 V clamping voltage at 57.1 A peak pulse current. It delivers 600 W peak pulse power (10/1000 μs), supports automotive-grade reliability (halogen-free, RoHS-compliant), and protects MOSFETs and ICs against inductive switching transients in power supply rails.

For engineers reviewing the P6SMB6.8A-M3/5B datasheet, P6SMB6.8A-M3/5B pinout, P6SMB6.8A-M3/5B application, or P6SMB6.8A-M3/5B equivalent, this page provides verified electrical parameters, thermal derating behavior, clamping performance under surge conditions, SMB package mechanical data, and validated alternatives for circuit protection design-in.

Technical Context

This TVS diode operates as a unidirectional clamping device: it remains high-impedance below 5.80 V (VWM), breaks down sharply between 6.45 V and 7.14 V (VBR), and limits transient voltages to ≤10.5 V at 57.1 A (IPPM). Its glass-passivated junction ensures stable avalanche characteristics and low incremental surge resistance.

Designed for automated SMT assembly on PCBs with 0.2" × 0.2" copper pads per terminal, it meets MSL Level 1 (reflow peak 260 °C), JESD201 Class 2 whisker resistance, and UL 94 V-0 flammability. Junction temperature range spans −65 °C to +150 °C, with thermal resistance R_θJA = 100 °C/W and R_θJL = 20 °C/W.

Key Specifications

Pinout & Package

SMB (DO-214AA) package: molded plastic case with matte tin-plated leads, 0.220" × 0.130" body size, cathode indicated by a band on one end. Mounting requires 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal for rated power dissipation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMAJ6.8A, P6SMB6.8A-M3/5B delivers 50% higher surge power headroom in the same general application class; versus 1.5SMC6.8A, it achieves equivalent protection in 30% less PCB area while maintaining full 600 W capability.

Availability

P6SMB6.8A-M3/5B is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, consumer USB port ESD shielding, and telecom DC input surge suppression requiring stable component supply and halogen-free compliance.

Supply support for P6SMB6.8A-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, efficiency, and application-specific performance.

The P6SMB Series targets cost-sensitive yet robust circuit protection needs in automotive, industrial, and communications infrastructure, delivering high-power transient suppression in compact SMB packaging with AEC-Q101 qualification options.

FAQ

What is the clamping voltage of P6SMB6.8A-M3/5B at its rated peak pulse current?

The P6SMB6.8A-M3/5B clamps to a maximum of 10.5 V when subjected to its rated peak pulse current of 57.1 A under the standard 10/1000 μs waveform. This value is measured at T_A = 25 °C with specified mounting conditions (0.2" × 0.2" copper pads), and represents the upper limit of voltage imposed on protected circuitry during worst-case surge events. The P6SMB6.8A-M3/5B maintains this clamping performance across its full operating temperature range with predictable derating above 25 °C.

Is P6SMB6.8A-M3/5B suitable for automotive applications?

Yes, P6SMB6.8A-M3/5B is halogen-free and RoHS-compliant (M3 suffix), and the P6SMB6.8A variant is available in AEC-Q101 qualified versions (e.g., P6SMB6.8AHM3_B). While the specific P6SMB6.8A-M3/5B ordering code does not carry the "_B" automotive suffix, its construction-glass-passivated junction, MSL Level 1 rating, and −65 °C to +150 °C operating range-meets foundational automotive environmental requirements. For certified automotive use, specify P6SMB6.8AHM3_B/H or P6SMB6.8AHM3_B/I.

How does the standoff voltage (V_WM) of P6SMB6.8A-M3/5B compare to its nominal voltage rating?

The P6SMB6.8A-M3/5B has a standoff voltage V_WM of 5.80 V, which is intentionally set below its nominal 6.8 V designation to ensure reliable blocking during normal operation. This 0.3 V margin prevents premature conduction while allowing sufficient headroom for typical 5 V rail tolerances (±5%). At V_WM, reverse leakage remains ≤1000 μA-low enough to avoid loading sensitive circuits-while still enabling rapid transition to avalanche conduction when transients exceed 6.45 V (V_{BR min}). The P6SMB6.8A-M3/5B thus balances noise immunity and surge responsiveness.

What is the thermal resistance profile of P6SMB6.8A-M3/5B, and how does it affect layout?

P6SMB6.8A-M3/5B has a typical junction-to-ambient thermal resistance (R_θJA) of 100 °C/W and junction-to-lead resistance (R_θJL) of 20 °C/W. These values assume mounting on 0.2" × 0.2" copper pads per terminal; reducing pad area increases R_θJA and risks thermal runaway during repetitive surges. Layout must allocate adequate copper area and consider thermal vias to inner layers if operating near 5.0 W steady-state dissipation. The P6SMB6.8A-M3/5B's R_θJL confirms efficient heat transfer to PCB traces, making it well-suited for compact, thermally dense designs.

Can P6SMB6.8A-M3/5B be used in bidirectional configurations?

No, P6SMB6.8A-M3/5B is a unidirectional TVS diode, identifiable by its cathode band marking and specified electrical parameters (e.g., V_BR, V_WM) for single-polarity operation. For bidirectional protection, Vishay offers the P6SMB6.8CA series (e.g., P6SMB6.8CA-M3/5B), which features symmetrical breakdown in both directions and no polarity marking. Using P6SMB6.8A-M3/5B in reverse-biased AC signal paths would result in forward conduction and failure. Always match the P6SMB6.8A-M3/5B's unidirectional architecture to DC or referenced signal lines.