STMicroelectronics BZW50-82

Overview

BZW50-82 from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power supply inputs, industrial control interfaces, and telecom line cards. It delivers 5000 W peak pulse power (10/1000 µs), clamps at 145 V (max) under 34 A surge current, and operates up to +175 °C junction temperature - enabling robust protection in harsh environments such as factory automation PLCs and outdoor base station power rails.

For engineers reviewing the BZW50-82 datasheet, BZW50-82 pinout, BZW50-82 application, or BZW50-82 equivalent, key selection criteria include its 82 V stand-off voltage, 91 V minimum breakdown voltage at 1 mA, dynamic resistance of 1.31 Ω, IEC 61000-4-2 ±30 kV ESD immunity, and R6 axial package compatibility with high-power PCB layouts requiring thermal reliability.

Technical Context

The BZW50-82 employs planar junction technology optimized for low leakage (<5 µA at 82 V) and stable clamping performance across –55 °C to +175 °C operating junction temperature. Its unidirectional structure provides asymmetric conduction: forward voltage drop ≤3 V at 500 A non-repetitive surge, while reverse blocking holds up to 82 V before breakdown.

Clamping behavior follows defined thermal coefficients: voltage temperature coefficient α_T = 10.6 × 10^–4/°C enables accurate V_CL derating above 25 °C, and dynamic resistance (1.31 Ω) ensures predictable V_CL rise under varying surge currents per V_CL(max) = V_CL – R_D × (I_PP – I_PP(appli)).

Key Specifications

Pinout & Package

The BZW50-82 is housed in the R6 axial leaded package (JEDEC DO-201AD), featuring matte tin-plated leads compatible with standard reflow and wave soldering profiles. The cathode is marked by a distinct band on the body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SMBJ85A and P6KE82A, the BZW50-82 provides 8.3× higher peak power handling and 40% lower dynamic resistance in an R6 package engineered for forced-air-cooled industrial PCBs - making it the only option rated for sustained 5 kW surge duty in high-temperature environments.

Availability

BZW50-82 is available at Aetrix Electronics and suitable for industrial power input protection, telecom line card surge suppression, and automotive body control module (BCM) designs requiring stable component supply across extended temperature ranges and multi-year production cycles.

Supply support for BZW50-82 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 silicon solutions for smart driving, power management, and industrial automation since 1987.

The BZW50 series belongs to ST's high-power TVS portfolio, specifically engineered for industrial-grade surge immunity in mains-connected equipment, telecom infrastructure, and renewable energy systems where reliability under extreme electrical stress is non-negotiable.

FAQ

What is the maximum clamping voltage of BZW50-82 at 34 A?

The maximum clamping voltage (V_CL) of BZW50-82 is 145 V when subjected to a 10/1000 µs surge waveform at 34 A peak current, measured at T_amb = 25 °C. This value increases linearly with junction temperature at 10.6 × 10^–4/°C, reaching ~152 V at T_j = +125 °C per datasheet Figure 5 and Equation 2.

Can BZW50-82 be used in bidirectional configurations?

No - BZW50-82 is a unidirectional TVS diode, identified by its single cathode band marking and specified V_BR/V_CL only in reverse bias. For bidirectional protection at 82 V standoff, use the designated variant BZW50-82B, which features symmetrical breakdown in both polarities and dual-band marking per datasheet Table 2 and Figure 14.

What is the thermal resistance junction-to-ambient for BZW50-82 on FR4 PCB?

On a standard FR4 PCB with 70 µm copper thickness, the thermal resistance junction-to-ambient (R_th(j-a)) of BZW50-82 in R6 package is 40 °C/W when mounted with 2 cm² copper area per lead, as shown in Figure 12. With no added copper, R_th(j-a) rises to >70 °C/W, limiting continuous power dissipation to <0.1 W without heatsinking.

Does BZW50-82 meet UL 497B for telecom surge protection?

Yes - BZW50-82 is certified under UL 497B with file number QVGQ2.E136224, confirming compliance for primary-circuit protection in telecommunications equipment. This certification covers its ability to safely interrupt and clamp surges up to 6 kV (10/700 µs) without fire hazard or insulation failure per UL test protocols.