Taiwan Semiconductor Corporation BZW04-342

Overview

BZW04-342 from Taiwan Semiconductor is a unidirectional transient voltage suppressor diode (TVS) designed for high-energy surge protection in DC power rails and signal lines. It features a 342 V working stand-off voltage, 380–420 V breakdown voltage at 1 mA, 548 V maximum clamping voltage at 0.75 A peak impulse current, and 400 W peak pulse power rating per 10/1000 μs waveform - deployed in automotive lighting control and industrial sensor interface circuits.

For engineers reviewing the BZW04-342 datasheet, BZW04-342 pinout, BZW04-342 application, or BZW04-342 equivalent, key selection criteria include clamping voltage margin vs. protected IC's absolute maximum rating, junction temperature derating above 25°C, unidirectional polarity marking, DO-41 mechanical fit, and AEC-Q101 qualification status for automotive-grade reliability validation.

Technical Context

The BZW04-342 operates as a silicon avalanche diode with controlled reverse-biased breakdown behavior. Its clamping action begins at V_BR = 380–420 V (tested at 1 mA), limiting transient voltages to ≤548 V under 0.75 A 10/1000 μs surge, while maintaining <1 μA leakage at 342 V DC bias.

Thermal design relies on R_θJA = 100 °C/W (on PCB, 10 mm leads) and R_θJL = 60 °C/W, enabling operation from −55°C to +175°C junction temperature. The device uses DO-204AL (DO-41) package with tin-plated leads compliant with J-STD-002 solderability and JESD201 Class 2 whisker resistance.

Key Specifications

Pinout & Package

DO-204AL (DO-41) is a hermetically sealed, axial-leaded glass-passivated package with cathode band marking. Lead spacing is standardized for manual and automated through-hole assembly; body diameter ≈ 2.7 mm, length ≈ 5.2 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ33CA and P6SMB330A, the BZW04-342 provides verified 342 V standoff and axial DO-41 mounting for legacy through-hole systems, while offering superior thermal dissipation and automotive qualification path - making it optimal for high-reliability 300+ V DC protection where leaded assembly remains standard.

Availability

BZW04-342 is available at Aetrix Electronics and suitable for automotive lighting modules, industrial PLC analog inputs, and DC power supply rail protection requiring stable component supply and long-term lifecycle support.

Supply support for BZW04-342 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 semiconductor manufacturer headquartered in Hsinchu, Taiwan, specializing in discrete power devices, TVS diodes, rectifiers, and thyristors since 1979.

The BZW04 series is part of TSC's high-power TVS portfolio engineered for robustness in harsh environments - targeting automotive, industrial control, and renewable energy applications where reliability under repetitive surge stress is critical.

FAQ

What is the polarity configuration of the BZW04-342?

The BZW04-342 is a unidirectional TVS diode, meaning it conducts only during reverse-biased overvoltage events. Its cathode is marked by a band on the DO-41 package body, and it must be installed with cathode toward the protected line and anode to ground. This configuration blocks forward current and clamps positive transients - unlike bidirectional variants such as BZW04-342B, which protect both polarities.

Does the BZW04-342 meet AEC-Q101 qualification?

The base BZW04-342 is not automatically AEC-Q101 qualified; qualification applies only to versions marked with the "H" suffix (e.g., BZW04-342H). These undergo stress testing per AEC-Q101 Rev D, including HTGB, AC-H3TRB, and temperature cycling. For automotive applications, specify BZW04-342H to ensure compliance - the standard BZW04-342 lacks this certification documentation.

What is the maximum clamping voltage of the BZW04-342 under surge conditions?

The BZW04-342 has a maximum clamping voltage (V_C) of 548 V when subjected to a 10/1000 μs surge waveform at 0.75 A peak impulse current. This value is guaranteed across temperature and lot variations per datasheet Table 2. It defines the upper voltage limit imposed on the protected circuit during transient events - critical for ensuring compatibility with downstream components' absolute maximum ratings.

Can the BZW04-342 be used in bidirectional protection applications?

No - the BZW04-342 is strictly unidirectional and cannot provide symmetrical clamping for AC or bipolar transients. For bidirectional protection at the same voltage level, the designated variant is BZW04-342B, which features matched breakdown in both directions and identical V_WM, V_BR, and V_C specs. Using BZW04-342 in place of BZW04-342B risks failure during negative-going surges.

How does the thermal performance of the BZW04-342 affect PCB layout?

The BZW04-342 has R_θJA = 100 °C/W on a PCB with 10 mm lead lengths, meaning each watt of sustained power raises junction temperature by 100°C above ambient. Since its steady-state power dissipation (P_D) is only 1 W at T_L = 75°C, layout must minimize thermal resistance: use ≥5 × 5 mm copper pads per lead, avoid narrow traces, and ensure airflow or heatsinking if operating near T_J = 175°C limits.