Taiwan Semiconductor Corporation BZW04-28B

Overview

BZW04-28B from Taiwan Semiconductor is a bidirectional transient voltage suppressor (TVS) diode in DO-41 package, designed for high-energy surge protection with 400W peak pulse power (10/1000μs), 28.2V working stand-off voltage, and 45.7V maximum clamping voltage at 8.8A peak impulse current. It protects automotive and industrial control circuits against ESD, EFT, and inductive switching transients.

For engineers reviewing the BZW04-28B datasheet, BZW04-28B pinout, BZW04-28B application, or BZW04-28B equivalent, key selection criteria include clamping voltage margin relative to protected IC V_CC, leakage current below 1μA at 28.2V, AEC-Q101 qualification status, thermal resistance (R_θJA = 100°C/W), and DO-41 lead-form compatibility with through-hole PCB layouts.

Technical Context

The BZW04-28B operates as a bidirectional avalanche diode, triggering when reverse or forward voltage exceeds its breakdown range of 31.4–34.7V at 1mA test current. Its low dynamic impedance enables rapid clamping response (<1ns) to fast transients like IEC 61000-4-2 ESD (±15kV air) and IEC 61000-4-4 EFT (±2kV).

Thermal design relies on junction-to-ambient resistance of 100°C/W (on PCB with 10mm leads) and maximum junction temperature of 175°C. The device sustains 400W non-repetitive surges per 10/1000μs waveform but derates linearly above 25°C ambient, delivering ~240W at 75°C.

Key Specifications

Pinout & Package

DO-204AL (DO-41) axial-leaded package with cathode band marking for unidirectional variants; BZW04-28B is bidirectional and lacks polarity marking-both leads are electrically symmetric.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ28CA and P6KE27CA, the BZW04-28B delivers tighter V_BR tolerance (±5.3%), lowest leakage (<1μA), and verified AEC-Q101 qualification-making it optimal for automotive and high-reliability embedded systems requiring long-term surge endurance and minimal standby current.

Availability

BZW04-28B is available at Aetrix Electronics and suitable for automotive power line protection, industrial sensor interface protection, LED driver overvoltage suppression, and ESD-sensitive microcontroller I/O protection requiring stable component supply across production lifecycles.

Supply support for BZW04-28B 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 specializing in discrete power devices, TVS diodes, rectifiers, and thyristors, with global distribution and AEC-Q101 validation capabilities.

The BZW04 series was engineered specifically for high-energy transient suppression in automotive and industrial environments, emphasizing low clamping ratio, tight parameter distribution, and robust thermal performance in axial-leaded packages.

FAQ

What is the peak pulse power rating of the BZW04-28B and under what test condition is it specified?

The BZW04-28B has a peak pulse power rating of 400W, measured using the standardized 10/1000μs double-exponential waveform per ANSI/IEEE C62.35. This rating applies at T_A = 25°C with non-repetitive pulses; derating is required above ambient temperatures per Figure 2 in the datasheet. The BZW04-28B maintains this rating due to its optimized silicon junction and DO-41 package thermal path.

Is the BZW04-28B unidirectional or bidirectional, and how does that affect PCB layout?

The BZW04-28B is a bidirectional TVS diode, meaning it provides symmetrical clamping for both positive and negative transients without polarity sensitivity. Unlike unidirectional variants (e.g., BZW04-28), it has no cathode band marking and can be mounted in either orientation on the PCB-eliminating orientation checks during assembly and simplifying layout for differential or AC-coupled protection paths.

Does the BZW04-28B meet AEC-Q101 requirements, and which version code indicates qualification?

The BZW04-28B itself is not AEC-Q101 qualified; however, the AEC-Q101 variant is designated as BZW04-28BH (with "H" suffix). Per Taiwan Semiconductor's ordering information, only parts marked with "H" undergo stress testing per AEC-Q101 Rev D, including temperature cycling, HTRB, and ESD. Standard BZW04-28B is suitable for industrial use but requires BZW04-28BH for automotive ECUs.

What is the maximum clamping voltage of the BZW04-28B, and at what current is it measured?

The maximum clamping voltage (V_C) of the BZW04-28B is 45.7V, measured at a peak impulse current (I_PP) of 8.8A under 10/1000μs waveform conditions. This value represents the worst-case voltage imposed on protected circuitry during a full-rated surge event and is guaranteed across the entire operating temperature range (−55°C to +175°C).

How does the thermal resistance of the BZW04-28B impact its steady-state power handling capability?

The BZW04-28B has a junction-to-ambient thermal resistance (R_θJA) of 100°C/W when mounted on a PCB with 10mm lead lengths. This limits its steady-state power dissipation to 1W at T_L = 75°C, as specified in absolute maximum ratings. For continuous power applications, thermal design must ensure lead temperature stays ≤75°C-typically achieved using copper pour or thermal vias adjacent to mounting pads.