Taiwan Semiconductor Corporation BZW04-145

Overview

BZW04-145 from Taiwan Semiconductor is a unidirectional transient voltage suppressor (TVS) diode designed for high-energy surge protection in automotive and industrial power rails. It features a 145 V working stand-off voltage, 161–179 V breakdown voltage at 1 mA, 400 W peak pulse power (10/1000 μs), clamping voltage of 234 V at 1.7 A peak impulse current, and operates from −55 °C to +175 °C junction temperature.

For engineers reviewing the BZW04-145 datasheet, BZW04-145 pinout, BZW04-145 application, or BZW04-145 equivalent, key selection criteria include its DO-41 package compatibility, AEC-Q101 qualification option (BZW04-145H), low leakage (<1 μA @ 145 V), and precise clamping performance for 12 V/24 V/48 V system overvoltage events.

Technical Context

The BZW04-145 is a silicon avalanche diode optimized for unidirectional clamping in DC power lines. Its 145 V V_WM ensures reliable blocking during normal operation while enabling fast response (<1 ns) to transients exceeding V_BR (161–179 V). The device uses planar passivated junction technology for stable breakdown and low thermal resistance (R_θJL = 60 °C/W).

It complies with ANSI/IEEE C62.35 for transient suppression and supports single-pulse 10/1000 μs waveform testing per IEC 61000-4-5. The 0.108 %/°C V_BR temperature coefficient ensures predictable voltage shift across its full operating range.

Key Specifications

Pinout & Package

Package: DO-204AL (DO-41), axial leaded, glass-passivated silicon junction. Cathode indicated by band marking. RoHS-compliant, halogen-free molding compound (UL 94V-0), pure tin-plated leads.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Littelfuse SMAJ150A and ON Semi 1.5KE150A, the BZW04-145 offers optimal balance of 145 V stand-off margin, DO-41 footprint compatibility, and AEC-Q101 qualification path-making it preferred for space-constrained automotive and industrial 24–48 V systems requiring validated reliability.

Availability

BZW04-145 is available at Aetrix Electronics and suitable for automotive ECU protection, industrial PLC input stages, LED driver overvoltage clamping, and telecom DC feed circuits requiring stable component supply across long production lifecycles.

Supply support for BZW04-145 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 Company (TSC) is a vertically integrated semiconductor manufacturer specializing in discrete power devices, TVS diodes, rectifiers, and MOSFETs for automotive, industrial, and consumer markets.

The BZW04 series was developed specifically for high-reliability transient suppression in harsh-environment applications, emphasizing AEC-Q101 compliance, extended temperature operation, and consistent clamping performance across voltage grades.

FAQ

What is the maximum clamping voltage of the BZW04-145 under standard test conditions?

The BZW04-145 has a maximum clamping voltage (V_C) of 234 V when subjected to a 10/1000 μs surge waveform at a peak impulse current (I_PP) of 1.7 A. This value is measured per ANSI/IEEE C62.35 and is guaranteed across the full operating temperature range. The BZW04-145 maintains this clamping performance consistently due to its planar junction construction and low dynamic impedance.

Is the BZW04-145 suitable for automotive applications?

Yes-the BZW04-145 is offered in an AEC-Q101 qualified version (BZW04-145H) with full qualification testing for temperature cycling, humidity bias, mechanical shock, and high-temperature operating life. Its −55 °C to +175 °C junction temperature range and DO-41 mechanical robustness make the BZW04-145 appropriate for engine control modules, body control units, and ADAS power supplies where transient immunity is critical.

How does the BZW04-145 differ from bidirectional variants like BZW04-145B?

The BZW04-145 is unidirectional and features a cathode band marking; it conducts only during positive transients on the cathode relative to anode. The BZW04-145B is bidirectional, with symmetrical breakdown in both polarities and no polarity marking. Both share identical V_WM, V_BR, and V_C ratings, but the BZW04-145 is selected for DC rail protection where polarity is fixed, while BZW04-145B suits AC or floating signal line protection.

What is the thermal resistance of the BZW04-145, and how does it affect PCB layout?

The BZW04-145 has a junction-to-lead thermal resistance (R_θJL) of 60 °C/W and junction-to-ambient resistance (R_θJA) of 100 °C/W on a 10 mm lead length PCB. For sustained surge duty, designers should use ≥5 × 5 mm copper pads per lead to achieve the rated R_θJL; this minimizes thermal runaway risk and ensures the BZW04-145 remains within its 175 °C T_JMAX limit during repetitive events.

Can the BZW04-145 replace older 1N6277 series TVS diodes?

Yes-the BZW04-145 is a functional and mechanical upgrade to the 1N6277A (140 V V_WM). It offers tighter V_BR tolerance (161–179 V vs. 154–170 V), lower clamping voltage (234 V vs. 243 V), and AEC-Q101 qualification path. The DO-41 package and axial lead form factor ensure drop-in compatibility; however, verify layout clearance and thermal pad area meet BZW04-145's 60 °C/W R_θJL requirement.