STMicroelectronics BZW50-180B

Overview

BZW50-180B from STMicroelectronics is a bidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in industrial power supplies and telecom infrastructure. It delivers 5000 W peak pulse power (10/1000 µs), clamps at 322 V (max) under 16 A surge, and operates up to +175 °C junction temperature - enabling robust protection of AC mains inputs and DC bus lines against IEC 61000-4-4 level 4 (4 kV) and IEC 61000-4-2 (30 kV contact/air discharge).

For engineers reviewing the BZW50-180B datasheet, BZW50-180B pinout, BZW50-180B application, or BZW50-180B equivalent, this page provides verified electrical parameters, thermal derating curves, R6 package mechanical data, and direct comparison with functionally aligned TVS alternatives for high-voltage AC/DC front-end design.

Technical Context

The BZW50-180B uses planar silicon junction technology optimized for low leakage (<5 µA at 180 V) and stable clamping over temperature (α_T = 10.8 × 10⁻⁴/°C). Its bidirectional architecture supports symmetrical surge suppression on AC lines without polarity constraints.

It exhibits dynamic resistance of 6.31 Ω at 10/1000 µs and 1.294 Ω at 8/20 µs, enabling precise voltage clamping during fast transients. Junction capacitance is <100 pF at 1 V reverse bias, minimizing signal distortion in high-frequency power circuits.

Key Specifications

Pinout & Package

The BZW50-180B is housed in the axial-leaded R6 package (JEDEC DO-201AD), featuring two electrically symmetric terminals with no anode/cathode distinction due to its bidirectional construction. Leads are matte tin-plated for solderability and RoHS compliance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ180CA and 1.5KE180CA, the BZW50-180B uniquely combines 5 kW surge rating, UL 497B listing, and sub-5 µA leakage - making it the sole choice for certified front-end protection in Class I industrial power systems requiring full IEC 61000-4-2/4-4 compliance.

Availability

BZW50-180B is available at Aetrix Electronics and suitable for AC mains input protection, telecom line interface, DC bus overvoltage clamp, and motor drive inverter stage applications requiring stable component supply across extended product lifecycles.

Supply support for BZW50-180B 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, specializing in power management, analog, MEMS, and microcontroller technologies for industrial, automotive, and consumer markets.

The BZW50 series belongs to ST's high-power TVS portfolio, engineered specifically for front-end surge immunity in AC/DC power conversion systems where reliability under extreme thermal and electrical stress is mandatory.

FAQ

What is the maximum clamping voltage of BZW50-180B at 10 A (10/1000 µs)?

Per Table 2 in DS0662 Rev 8, the maximum clamping voltage is 322 V at 16 A (10/1000 µs). At 10 A, VCL is lower - calculated using VCL(max) = VCL − RD × (IPP − IPP_appli) = 322 V − 6.31 Ω × (16 A − 10 A) = 284.1 V. This value is confirmed by Figure 5 curve interpolation for 10/1000 µs pulses.

Can BZW50-180B be used in place of unidirectional BZW50-180?

No - BZW50-180B is bidirectional and lacks polarity marking; BZW50-180 is unidirectional with cathode bar marking. Substitution requires circuit redesign to accommodate symmetrical clamping and verify absence of DC bias that could forward-bias one junction. Reverse voltage ratings differ: BZW50-180 has VRM = 180 V, while BZW50-180B maintains 180 V in both directions.

Does BZW50-180B meet UL 497B for telecom surge protection?

Yes - UL 497B file number QVGQ2.E136224 is explicitly listed in the datasheet. This certification confirms suitability for primary protection in telecommunications equipment, including DSL, POTS, and PoE-powered devices, covering both differential- and common-mode surge paths per ANSI/UL 497B Annex D.

What is the thermal resistance junction-to-ambient for BZW50-180B on FR4 PCB?

Per Figure 12, R_th(j-a) is 4.5 °C/W with 5 cm² copper area per lead on 70 µm FR4. With minimal copper (0.5 cm²), R_th(j-a) rises to ~40 °C/W. Derating must follow Figure 3: at T_j = 125 °C, PPP drops to ~3700 W (10/1000 µs), not 5000 W - confirming thermal layout directly impacts surge capability.