STMicroelectronics BZW50-100B

Overview

BZW50-100B from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power rails and signal lines. It features a 100 V stand-off voltage (VRM), 111 V minimum breakdown voltage (VBR), 179 V clamping voltage (VCL) at 28 A (10/1000 µs), and 5000 W peak pulse power dissipation - deployed in industrial motor drives to safeguard IGBT gate drivers against ESD and lightning-induced transients.

For engineers reviewing the BZW50-100B datasheet, BZW50-100B pinout, BZW50-100B application, or BZW50-100B equivalent, key selection criteria include verified 179 V clamping at 28 A, bidirectional polarity, R6 axial package thermal robustness up to 175 °C junction temperature, and compliance with IEC 61000-4-2 (30 kV contact/air) and IEC 61000-4-4 level 4 (4 kV).

Technical Context

The BZW50-100B employs planar silicon junction technology optimized for low leakage (<5 µA at VRM) and stable clamping performance across -55 °C to +175 °C operating junction temperature. Its bidirectional architecture enables symmetrical surge suppression on AC-coupled or floating lines without polarity dependency.

Dynamic resistance is 2.01 Ω (10/1000 µs) and 0.400 Ω (8/20 µs), enabling precise VCL prediction via VCL = VCL₂₅°C × (1 + αT × (Tj − 25)) where αT = 10.7 × 10⁻⁴ /°C. The device sustains 3700 W at Tj = 175 °C per Figure 3, confirming derated high-power capability under thermal stress.

Key Specifications

Pinout & Package

The BZW50-100B is housed in an R6 axial leaded package (JEDEC DO-201AD), with cathode identified by a band on one end. Leads are matte tin-plated for solderability and RoHS compliance. Package dimensions: A = 8.6–9.1 mm, B = 25.4 mm, C = 8.6–9.1 mm, D = 1.2–1.3 mm.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar bidirectional TVS protection applications.

Compared with SMBJ100A and P6SMB100CA, BZW50-100B uniquely delivers 5000 W surge handling in a bidirectional R6 package with full IEC 61000-4-2/4-4 certification - making it the sole option for high-energy AC-coupled protection where polarity independence and thermal endurance are mandatory.

Availability

BZW50-100B is available at Aetrix Electronics and suitable for industrial motor drives, telecom line interfaces, power supply input stages, and automotive body control modules requiring stable component supply across extended product lifecycles.

Supply support for BZW50-100B 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, delivering intelligent power, analog, MEMS, and microcontroller solutions for industrial, automotive, and consumer markets.

The BZW50 series belongs to ST's high-power TVS portfolio, engineered specifically for robust, high-reliability surge protection in harsh-environment applications where thermal stability, low leakage, and certified immunity are non-negotiable.

FAQ

What is the maximum clamping voltage of BZW50-100B under a 10/1000 µs surge?

The maximum clamping voltage (VCL) is 179 V at a peak pulse current (IPP) of 28 A for the 10/1000 µs waveform, measured at Tamb = 25 °C per Table 2. This value increases linearly with junction temperature using αT = 10.7 × 10⁻⁴ /°C, reaching ~192 V at Tj = 125 °C.

Can BZW50-100B be used in place of a unidirectional TVS like BZW50-100?

No - BZW50-100B is bidirectional and lacks a defined anode/cathode polarity, whereas BZW50-100 is unidirectional with a marked cathode. Substituting them requires verifying circuit topology: bidirectional use is mandatory for AC lines or floating nodes; unidirectional is required for DC rails with defined ground reference.

Does BZW50-100B meet UL 497B for telecom surge protection?

Yes - BZW50-100B carries UL 497B file number QVGQ2.E136224, certifying its suitability for primary and secondary circuit protection in telecommunications equipment per UL 497B Annex B requirements for impulse withstand and insulation coordination.

What is the thermal resistance junction-to-ambient for BZW50-100B on a standard FR4 PCB?

On a standard epoxy FR4 board with 70 µm copper thickness, Rth(j-a) is approximately 40 °C/W when mounted with 2 cm² copper area per lead (Figure 12). With minimal copper (0.5 cm²), Rth(j-a) rises to ~70 °C/W - critical for thermal design when operating near 175 °C junction limit.