Taiwan Semiconductor Corporation BZW04-7V0B

Overview

BZW04-7V0B from Taiwan Semiconductor is a unidirectional transient voltage suppressor diode (TVS) designed for primary overvoltage protection in DC power rails and signal lines. It features a 7.02 V working stand-off voltage, 7.79–8.61 V breakdown voltage at 10 mA, 400 W peak pulse power (10/1000 µs), 33.0 A maximum peak impulse current, and clamps to ≤12.1 V at rated surge current. It is used in automotive lighting control modules to protect microcontroller I/O pins from load-dump and ESD transients.

For engineers reviewing the BZW04-7V0B datasheet, BZW04-7V0B pinout, BZW04-7V0B application, or BZW04-7V0B equivalent, key selection criteria include its DO-41 package compatibility, unidirectional polarity marking, 12.1 V clamping performance at 33 A, and AEC-Q101 qualification option (BZW04-7V0BH).

Technical Context

The BZW04-7V0B operates as a silicon avalanche diode with fast response (<1 ns) to transient overvoltages. Its unidirectional configuration provides reverse-biased clamping only - forward conduction is not intended for surge handling. The device uses planar junction technology to ensure stable V_BR tolerance (±5%) and low leakage (<200 µA at 7.02 V).

Thermal design relies on its DO-41 package's 60 °C/W junction-to-lead resistance and 100 °C/W junction-to-ambient rating on standard PCB pads. It sustains 175 °C maximum junction temperature and supports repetitive surge events only when derated per Fig.2 in the datasheet.

Key Specifications

Pinout & Package

Package: DO-204AL (DO-41), axial leaded, epoxy-molded, RoHS-compliant, halogen-free, UL 94V-0 rated. Cathode indicated by band marking; anode is unmarked end.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ7.0A and P6KE7.0A, the BZW04-7V0B offers identical V_WM and P_PK in a smaller DO-41 package with verified AEC-Q101 availability, making it optimal for cost-sensitive, high-volume automotive electronics requiring proven through-hole reliability.

Availability

BZW04-7V0B is available at Aetrix Electronics and suitable for automotive lighting control, industrial PLC I/O protection, and USB port ESD protection requiring stable component supply and long-term lifecycle support.

Supply support for BZW04-7V0B 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 developed specifically for high-reliability transient suppression in harsh-environment applications, emphasizing AEC-Q101 qualification, tight V_BR tolerance, and consistent clamping performance across temperature.

FAQ

What is the polarity configuration of the BZW04-7V0B?

The BZW04-7V0B is a unidirectional TVS diode, with cathode identified by a band marking on the DO-41 package. It clamps only in reverse bias - forward conduction is not part of its surge protection function. This configuration makes it suitable for DC rail protection where polarity is fixed, such as 12 V battery-fed circuits. The BZW04-7V0B must be oriented with cathode toward the higher-potential side of the protected node.

Does the BZW04-7V0B meet AEC-Q101 reliability standards?

The BZW04-7V0B itself is not AEC-Q101 qualified; however, the AEC-Q101 variant is explicitly designated as BZW04-7V0BH in the ordering code. That version undergoes full stress testing per AEC-Q101 including HTGB, HTRB, and temperature cycling. For automotive applications requiring qualification evidence, specify BZW04-7V0BH - the BZW04-7V0B remains suitable for industrial or commercial use where qualification is not mandated.

What is the maximum clamping voltage of the BZW04-7V0B at its rated surge current?

The BZW04-7V0B has a maximum clamping voltage (V_C) of 12.1 V when subjected to its rated peak impulse current of 33.0 A under the standard 10/1000 µs waveform. This value is measured per ANSI/IEEE C62.35 and guarantees that protected circuitry downstream will not experience voltages exceeding 12.1 V during a full-rated transient event. The BZW04-7V0B maintains this clamping performance across its specified operating temperature range.

Can the BZW04-7V0B be used in bidirectional signal line protection?

No - the BZW04-7V0B is strictly unidirectional and lacks symmetrical breakdown characteristics required for AC or bidirectional signal protection. For such applications, the BZW04-7V0B's bidirectional counterpart, BZW04-7V0BB (if offered), or a dedicated bidirectional TVS like SMAJ7.0CA must be selected. Using the BZW04-7V0B on a bidirectional line risks forward conduction during normal signal swings and inadequate clamping during negative transients.

What is the thermal resistance specification for the BZW04-7V0B in standard mounting conditions?

The BZW04-7V0B has a junction-to-lead thermal resistance (R_θJL) of 60 °C/W and a junction-to-ambient thermal resistance (R_θJA) of 100 °C/W when mounted on a printed circuit board with 10 mm lead length. These values assume standard copper pad layout (5 × 5 mm per terminal) and define the device's ability to dissipate heat during surge events. Exceeding 175 °C junction temperature - calculable using R_θJL and measured lead temperature - risks permanent parametric shift in the BZW04-7V0B.