Vishay General Semiconductor - Diodes Division P4SMA68A-M3/61

Overview

P4SMA68A-M3/61 from Vishay General Semiconductor is a unidirectional surface-mount Transient Voltage Suppressor (TVS) diode designed for robust overvoltage protection in power and signal lines. It features a 68 V breakdown voltage (V_BR = 64.6–71.4 V at 1 mA), 58.1 V standoff voltage (V_WM), 92 V clamping voltage (V_C = 92 V at I_PPM = 4.3 A), and 400 W peak pulse power rating with 10/1000 µs waveform - deployed to safeguard MOSFETs, ICs, and sensor signal lines against inductive switching transients and ESD in industrial and automotive electronics.

For engineers reviewing the P4SMA68A-M3/61 datasheet, P4SMA68A-M3/61 pinout, P4SMA68A-M3/61 application, or P4SMA68A-M3/61 equivalent, this device offers halogen-free, RoHS-compliant construction in SMA (DO-214AC) package, AEC-Q101 qualification readiness (via M3 suffix), and verified clamping performance under repetitive surge conditions - critical for reliability-focused board-level transient suppression design.

Technical Context

The P4SMA68A-M3/61 operates as a unidirectional avalanche diode, conducting only when reverse voltage exceeds its specified breakdown threshold. Its glass-passivated junction ensures stable V_BR tolerance (±5%) and low incremental surge resistance, enabling precise, repeatable clamping during fast-rising transients (response time < 1 ns).

Thermal performance is defined by R_θJA = 120 °C/W (junction-to-ambient, on minimum pad layout) and R_θJL = 30 °C/W (junction-to-lead), supporting operation up to T_J = 150 °C. The device sustains 40 A non-repetitive forward surge current (I_FSM, 8.3 ms half-sine) and meets MSL Level 1 per J-STD-020 with 260 °C reflow peak.

Key Specifications

Pinout & Package

Package: SMA (DO-214AC), surface-mount, molded plastic case with matte tin-plated leads; cathode indicated by band on body; compliant with UL 94 V-0 flammability rating.

Key Features

Applications

Equivalent & Alternatives

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

Compared with P4SMA68A-M3/61, SMBJ68A offers higher surge capacity at the cost of board area, while 1.5SMC68A provides identical electrical performance in the same SMA package with relaxed leakage - making it viable for cost- or supply-chain-driven substitutions where leakage is not critical.

Availability

P4SMA68A-M3/61 is available at Aetrix Electronics and suitable for automotive power rail protection, industrial sensor interface hardening, consumer power adapter output safeguarding, and telecom DC input surge suppression requiring stable component supply, halogen-free compliance, and AEC-Q101 traceability pathways.

Supply support for P4SMA68A-M3/61 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 P4SMA68A-M3/61 belongs to Vishay's TRANSZORB® TVS family, engineered for high-energy transient suppression in space-constrained, high-reliability applications including automotive, industrial control, and communications infrastructure.

FAQ

What is the clamping voltage of the P4SMA68A-M3/61 under a 10/1000 µs surge?

The P4SMA68A-M3/61 has a maximum clamping voltage (V_C) of 92 V at a peak pulse current (I_PPM) of 4.3 A with a 10/1000 µs waveform. This value is measured under standardized test conditions and represents the upper limit of voltage seen by downstream components during a surge event. The P4SMA68A-M3/61 maintains this clamping performance consistently due to its glass-passivated junction and low dynamic impedance.

Is the P4SMA68A-M3/61 suitable for automotive applications?

Yes - the P4SMA68A-M3/61 carries the M3 suffix indicating halogen-free, RoHS-compliant construction and is part of the AEC-Q101-qualified P4SMA series (with HM3 variants). While P4SMA68A-M3/61 itself is commercial-grade, its design basis, thermal robustness (T_J max = 150 °C), and surge ratings align with automotive subsystem requirements such as body control modules and sensor interfaces. For full qualification, specify P4SMA68A-HM3_A/H.

What does the "-M3/61" suffix mean in P4SMA68A-M3/61?

The "-M3" denotes halogen-free, RoHS-compliant packaging per Vishay's material categorization standard; "/61" specifies packaging in 7-inch diameter plastic tape and reel, with 1800 units per reel. This format ensures compatibility with high-speed pick-and-place equipment and supports automated manufacturing. The P4SMA68A-M3/61 thus combines environmental compliance with SMT process readiness.

How does the P4SMA68A-M3/61 compare to bidirectional TVS diodes like P4SMA68CA?

The P4SMA68A-M3/61 is unidirectional and intended for DC line protection where polarity is fixed (e.g., +12 V rail to ground), offering lower leakage (<1 µA at V_WM) and tighter V_BR tolerance. In contrast, P4SMA68CA is bidirectional, suited for AC or floating signal lines (e.g., RS-485), but exhibits higher leakage (≤5 µA) and symmetric clamping in both directions. The P4SMA68A-M3/61 cannot replace P4SMA68CA in AC-coupled applications without circuit redesign.

What is the thermal resistance of the P4SMA68A-M3/61, and how does it affect layout?

The P4SMA68A-M3/61 has a typical junction-to-ambient thermal resistance (R_θJA) of 120 °C/W when mounted on minimum recommended 0.2" × 0.2" (5.0 mm × 5.0 mm) copper pads per terminal. To maintain safe junction temperatures under sustained power dissipation, PCB layout must provide adequate copper area and avoid thermal bottlenecks. Exceeding T_J = 150 °C risks parametric shift or failure - hence thermal derating per Figure 2 in the datasheet is essential for high-ambient designs using P4SMA68A-M3/61.