STMicroelectronics BZW50-150

Overview

BZW50-150 from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power supply and industrial interface circuits. It features a 150 V stand-off voltage, 166 V minimum breakdown voltage at 1 mA, 269 V maximum clamping voltage at 19 A (10/1000 µs), 5000 W peak pulse power rating, and operates up to +175 °C junction temperature - deployed in telecom AC/DC front-ends and motor drive DC bus lines.

For engineers reviewing the BZW50-150 datasheet, BZW50-150 pinout, BZW50-150 application, or BZW50-150 equivalent, key selection criteria include clamping voltage margin vs. protected IC V_DS(max), leakage current at operating temperature, dynamic resistance under fast transients, and R6 package thermal performance on FR4 PCBs with limited copper area.

Technical Context

The BZW50-150 uses planar junction silicon technology optimized for low leakage (<5 µA at 150 V, 25 °C) and stable V_BR temperature coefficient (α_T = 10.8 × 10⁻⁴/°C). Its unidirectional configuration enables asymmetric surge handling - forward conduction during positive overvoltage, reverse blocking until breakdown.

Clamping behavior follows V_CL(T_j) = V_CL(25 °C) × [1 + α_T × (T_j − 25)], with dynamic resistance R_D = 4.50 Ω (10/1000 µs) enabling predictable voltage overshoot under defined surge currents. It meets IEC 61000-4-2 level 4 (±30 kV contact/air) and IEC 61000-4-4 level 4 (4 kV).

Key Specifications

Pinout & Package

The BZW50-150 is housed in the axial-leaded R6 package (JEDEC DO-201AD), featuring two terminals: anode and cathode. Cathode identified by a bar marking on the body. 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 transient voltage suppression applications.

Compared with SMBJ150A and 1.5KE150A, the BZW50-150 delivers 3.3× and 3.3× higher peak pulse power respectively, tighter clamping (269 V vs. 243 V/250 V), and certified compliance with telecom-grade ESD and surge standards - making it the only option qualified for high-reliability front-end protection in harsh environments.

Availability

BZW50-150 is available at Aetrix Electronics and suitable for AC/DC power supplies, industrial motor drives, telecom line interfaces, and automotive BCMs requiring stable component supply across long production lifecycles.

Supply support for BZW50-150 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, designing and manufacturing silicon solutions for automotive, industrial, and power management applications.

The BZW50 series belongs to ST's high-power TVS portfolio, engineered specifically for robust front-end surge protection in systems exposed to lightning, ESD, and load-dump transients - emphasizing thermal stability, low leakage, and international safety certification.

FAQ

What is the maximum clamping voltage of BZW50-150 under a 10/1000 µs surge?

The maximum clamping voltage is 269 V at 19 A for a 10/1000 µs waveform, measured at T_amb = 25 °C. This value increases linearly with junction temperature using α_T = 10.8 × 10⁻⁴/°C, reaching ~292 V at T_j = 125 °C per the V_CL(T_j) formula in DS0662.

Can BZW50-150 be used in bidirectional protection circuits?

No - BZW50-150 is unidirectional. For bidirectional protection at 150 V stand-off, use the BZW50-150B variant, which has symmetrical breakdown in both polarities and identical clamping performance in either direction per Table 2.

What is the thermal resistance junction-to-ambient for BZW50-150 on standard FR4?

On a standard epoxy FR4 board with 70 µm copper thickness, R_th(j-a) is approximately 40 °C/W for a 1 cm² copper pad per lead (Figure 12). With 2.5 cm² total copper area, thermal resistance drops to ~22 °C/W, enabling sustained 6.5 W dissipation at T_amb = 70 °C.

Does BZW50-150 meet UL 497B for telecom surge protection?

Yes - it carries UL 497B file number QVGQ2.E136224, certifying compliance for use in telecommunications primary protector applications including POTS, xDSL, and ISDN interfaces per ANSI/UL 497B Edition 5.