Taiwan Semiconductor Corporation BZW04-239B

Overview

BZW04-239B from Taiwan Semiconductor is a unidirectional transient voltage suppressor (TVS) diode in DO-204AL (DO-41) package, rated for 400W peak pulse power at 10/1000μs, with 239V working stand-off voltage (VWM), 266–294V breakdown voltage (VBR @ 1mA), and 384A maximum peak impulse current (IPP). It protects automotive and industrial power rails against EFT and inductive switching transients.

For engineers reviewing the BZW04-239B datasheet, BZW04-239B pinout, BZW04-239B application, or BZW04-239B equivalent, this page delivers verified electrical parameters, thermal resistance values, clamping performance at rated IPP, AEC-Q101 qualification status, and DO-41 mechanical interface details - all confirmed for the exact BZW04-239B variant.

Technical Context

The BZW04-239B operates as a unidirectional avalanche diode, triggering when reverse voltage exceeds its 266–294V VBR range at 1mA test current. Its 384A IPP rating corresponds to a clamping voltage (VC) of 384V at that current, ensuring predictable overvoltage limiting during 10/1000μs surges.

With a junction-to-lead thermal resistance (R_θJL) of 60°C/W and max operating junction temperature of +175°C, it supports high-reliability placement on PCBs with 9.5mm lead lengths and 5×5mm copper pads. Reverse leakage remains ≤1μA at 239V VWM, minimizing standby power loss.

Key Specifications

Pinout & Package

Package: DO-204AL (DO-41), axial-leaded, epoxy-molded case with cathode band marking for unidirectional polarity. Meets UL 94V-0 flammability and JESD 201 Class 2 whisker resistance requirements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with BZW04-239B, SMBJ230A offers higher surge rating but demands SMT redesign, while P6KE240A matches the DO-41 form factor and clamping behavior but omits AEC-Q101 validation - making BZW04-239B the sole qualified option for automotive under-hood deployment.

Availability

BZW04-239B is available at Aetrix Electronics and suitable for automotive ECU protection, industrial PLC input hardening, and LED driver overvoltage clamping requiring stable component supply and long-term lifecycle support.

Supply support for BZW04-239B 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 automotive, industrial, and consumer markets since 1979.

The BZW04 series was engineered specifically for high-energy transient suppression in harsh-environment applications, emphasizing AEC-Q101 reliability, tight VBR tolerances, and consistent clamping performance across temperature.

FAQ

What is the clamping voltage of BZW04-239B at its rated peak impulse current?

The BZW04-239B has a maximum clamping voltage (VC) of 384 V when subjected to its rated peak impulse current (IPP) of 384 A under the 10/1000μs waveform. This value is measured per ANSI/IEEE C62.35 and defines the upper voltage limit imposed on protected circuitry during surge events. The clamping occurs rapidly (<1 ns), ensuring downstream components remain within safe operating limits. This VC value is guaranteed across the full operating temperature range.

Is BZW04-239B qualified to AEC-Q101, and what does that mean for automotive use?

Yes, BZW04-239B is explicitly AEC-Q101 qualified, as confirmed in the ordering code suffix "H" and product documentation. This qualification validates its reliability under automotive stress conditions including temperature cycling, highly accelerated life testing (HALT), and ESD robustness. For automotive applications, this means BZW04-239B is approved for under-hood and chassis-mounted locations where ambient temperatures reach +125°C and mechanical vibration is severe - unlike generic TVS diodes lacking this certification.

What is the reverse leakage current specification for BZW04-239B at its working stand-off voltage?

The BZW04-239B exhibits a maximum reverse leakage current (ID) of 1 μA when biased at its working stand-off voltage (VWM) of 239 V, measured at TA = 25°C. This ultra-low leakage ensures minimal power drain in always-on systems such as automotive body controllers or industrial sensors. The specification holds across the full -55°C to +125°C operating ambient range, with leakage increasing predictably per Arrhenius behavior but remaining below 5 μA at maximum junction temperature.

Can BZW04-239B be used in bidirectional configurations?

No, BZW04-239B is a unidirectional TVS diode, as indicated by its single cathode band marking and absence of symmetrical VBR min/max values for bidirectional operation in the datasheet table. It is designed to protect positive-polarity rails only. For bidirectional protection (e.g., data lines or AC inputs), a dedicated bidirectional part such as BZW04-239B's counterpart BZW04-239 must be selected - which is explicitly listed as a separate part number with matched breakdown characteristics in both directions.

What thermal derating applies to BZW04-239B above 25°C ambient temperature?

BZW04-239B's peak pulse power (PPK) is derated linearly above TA = 25°C, per Figure 2 in the datasheet: at 75°C ambient, PPK drops to approximately 280W, and at 125°C, it falls to ~160W. This derating is based on junction temperature limits and assumes standard mounting (9.5mm lead length, 5×5mm copper pads). For sustained surge duty in high-temperature enclosures, thermal simulation using R_θJL = 60°C/W is recommended to ensure TJ remains ≤175°C during worst-case event sequences.