Taiwan Semiconductor Corporation P6SMB68

Overview

P6SMB68 from Taiwan Semiconductor is a unidirectional 600W surface-mount transient voltage suppressor (TVS) diode with a nominal breakdown voltage of 68V, clamping voltage of 98V at 6.4A peak pulse current, and stand-off voltage of 55.1V. It features DO-214AA (SMB) packaging, 10ns response time, and is designed for overvoltage protection in DC power rails of switching mode power supplies and consumer electronics.

For engineers reviewing the P6SMB68 datasheet, P6SMB68 pinout, P6SMB68 application, or P6SMB68 equivalent, key selection criteria include its 68V V_BR (min/max: 61.2–74.8V), 98V clamping voltage at 6.4A, 1μA max reverse leakage at 55.1V, 150°C junction rating, and compliance with ISO 7637-2 Pulse 1/2a/2b/3a/3b for automotive transients.

Technical Context

The P6SMB68 operates as a unidirectional avalanche diode, triggered when reverse voltage exceeds its specified breakdown range (61.2–74.8V at 1mA test current). Its glass-passivated junction ensures stable V_BR tolerance and low leakage (<1μA at V_WM = 55.1V), while its 10/1000μs waveform-rated 600W peak pulse power enables robust surge handling per IEC 61000-4-5 and ISO 7637-2 standards.

Thermal performance is defined by R_θJC = 10°C/W and R_θJA = 55°C/W, supporting operation from –55°C to +150°C. The device uses a single-die configuration in DO-214AA (SMB) package with matte tin-plated leads compliant with J-STD-002 solderability and JESD 201 Class 2 whisker resistance.

Key Specifications

Pinout & Package

DO-214AA (SMB) package: molded plastic case with cathode band marking; matte tin-plated leads; polarity indicated by cathode band on unidirectional variant; weight ≈ 0.090g; meets J-STD-020 moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ64A and 1.5SMC68A, the P6SMB68 offers balanced clamping performance (98V), wide V_BR tolerance (61.2–74.8V), and compact SMB footprint - making it optimal for cost-sensitive, space-constrained 12–24V DC systems requiring ISO 7637-2 compliance.

Availability

P6SMB68 is available at Aetrix Electronics and suitable for switching mode power supplies, consumer display electronics, and automotive body control modules requiring stable component supply and full traceability.

Supply support for P6SMB68 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

Taiwan Semiconductor Corporation (TSC) is a vertically integrated analog and discrete semiconductor manufacturer headquartered in Hsinchu, Taiwan, serving global industrial, automotive, and consumer markets since 1979.

The P6SMB68 belongs to TSC's P6SMB series of 600W surface-mount TVS diodes engineered specifically for high-reliability DC rail protection in automotive and industrial equipment where ISO 7637-2 and RoHS compliance are mandatory.

FAQ

What is the breakdown voltage range of the P6SMB68?

The P6SMB68 has a guaranteed breakdown voltage range of 61.2V to 74.8V at 1mA test current, measured per ANSI/IEEE C62.35. This min/max specification reflects production tolerance and ensures consistent clamping behavior across batches. The P6SMB68 achieves this using a glass-passivated silicon junction optimized for stability under thermal cycling and long-term bias stress.

Is the P6SMB68 unidirectional or bidirectional?

The P6SMB68 is a unidirectional TVS diode, indicated by the absence of "C" or "CA" suffix. Its cathode band marks the terminal that connects to the higher-potential side of the protected line. Bidirectional variants (e.g., P6SMB68C) exist in the same family but are distinct orderable parts with symmetrical breakdown in both directions - the P6SMB68 itself conducts only in forward bias and clamps only in reverse.

What is the maximum clamping voltage of the P6SMB68 and under what conditions?

The P6SMB68 has a maximum clamping voltage (V_C) of 98V at a peak pulse current (I_PPM) of 6.4A, tested with the standard 10/1000μs double-exponential waveform. This value represents worst-case voltage seen by downstream circuitry during a full-power surge event. The P6SMB68 maintains this clamping performance across its full operating temperature range (–55°C to +150°C) with minimal derating.

Does the P6SMB68 meet automotive transient immunity standards?

Yes, the P6SMB68 is explicitly validated to meet ISO 7637-2 requirements for Pulse 1 (inductive load dump), Pulse 2a/2b (supply interruption and switching transients), and Pulse 3a/3b (capacitive coupling), as stated in the official Taiwan Semiconductor datasheet (Version Q2209). This makes the P6SMB68 suitable for front-end protection in automotive body electronics, infotainment power supplies, and telematics modules without additional qualification.

What is the thermal resistance profile of the P6SMB68 and how does it affect PCB layout?

The P6SMB68 has a junction-to-case thermal resistance (R_θJC) of 10°C/W and junction-to-ambient (R_θJA) of 55°C/W, measured on standard FR-4 with recommended pad layout. To maintain T_J ≤ 150°C under 600W surge, PCB copper area must be sufficient to dissipate heat between pulses - typically ≥ 40mm² of 2oz copper connected to both terminals. The P6SMB68's low R_θJC enables effective heat transfer to heatsink pads, unlike smaller SOD-123 packages.