STMicroelectronics BZW50-15RL

Overview

BZW50-15RL from STMicroelectronics is a unidirectional transient voltage suppression (TVS) diode designed for high-energy surge protection in power supply and interface lines. It delivers 5000 W peak pulse power (10/1000 µs), clamps at 26.9 V (max) under 186 A surge, and operates up to +175 °C junction temperature - enabling robust protection in industrial SMPS, telecom DC feeds, and automotive power rails.

For engineers reviewing the BZW50-15RL datasheet, BZW50-15RL pinout, BZW50-15RL application, or BZW50-15RL equivalent, key selection criteria include clamping voltage vs. surge current, temperature coefficient of breakdown voltage (8.8 × 10⁻⁴ /°C), dynamic resistance (0.046 Ω), leakage current ≤5 µA at 15 V, and R6 package thermal performance on FR4 PCBs.

Technical Context

The BZW50-15RL uses planar silicon junction technology optimized for low leakage (<5 µA at VRM = 15 V) and stable VBR drift over temperature (αT = 8.8 × 10⁻⁴ /°C). Its unidirectional configuration provides asymmetric conduction: forward surge handling up to 500 A (IFSM), reverse standoff at 15 V, and clamping at 26.9 V during 10/1000 µs transients.

Thermal design is enabled by its R6 package with 2.05 g mass and defined thermal impedance (Zth(j-a) = ~40 °C/W for single pulse on FR4). Dynamic resistance (RD = 0.046 Ω) ensures predictable VCL rise under increasing IPP, supporting accurate system-level surge margining per IEC 61000-4-4 Level 4 (4 kV).

Key Specifications

Pinout & Package

The BZW50-15RL is housed in the R6 axial-leaded 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 unidirectional TVS diode applications.

Compared with SMBJ15A and P6KE15A, the BZW50-15RL provides 8.3× higher pulse power, 175 °C junction rating, and UL 497B listing - making it uniquely suited for industrial, automotive, and telecom infrastructure where sustained surge immunity and safety compliance are mandatory.

Availability

BZW50-15RL is available at Aetrix Electronics and suitable for industrial SMPS input protection, automotive BCM power rail hardening, and telecom DC feed surge suppression requiring stable component supply across extended temperature and lifecycle demands.

Supply support for BZW50-15RL 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, MCU, and automotive-grade components with vertical manufacturing control.

The BZW50 series belongs to ST's high-power TVS portfolio, engineered specifically for industrial and automotive surge immunity - emphasizing thermal robustness, low leakage, and compliance with UL, IEC, and AEC-Q200-aligned reliability standards.

FAQ

What is the maximum surge current the BZW50-15RL can handle in a 10/1000 µs waveform?

The BZW50-15RL handles up to 186 A peak pulse current under 10/1000 µs conditions while clamping to 26.9 V maximum. This value is measured at Tamb = 25 °C and assumes proper PCB copper area (≥2 cm² per lead) to maintain thermal limits. Derating applies above 25 °C ambient per Figure 3 in DS0662.

Is the BZW50-15RL suitable for bidirectional surge protection?

No - BZW50-15RL is unidirectional and must be installed with cathode toward the protected line. For bidirectional protection, use the BZW50-15B variant, which features symmetrical clamping in both polarities and identical electrical ratings except for polarity-independent marking and red tape on both sides per datasheet Figure 19.

Does the BZW50-15RL require a heatsink for 5000 W pulse dissipation?

No external heatsink is required for single-pulse 5000 W events, as energy is dissipated thermally within the silicon junction. However, PCB layout must provide ≥2 cm² of 70 µm copper per lead (per Figure 12) to achieve specified Rth(j-a) and prevent cumulative heating during repetitive surges.

How does the 8.8 × 10⁻⁴ /°C voltage temperature coefficient affect system design?

This coefficient means VBR increases by 0.088 V/°C above 25 °C. At +125 °C, VBR rises to ~16.9 V - still below VCL (26.9 V), ensuring safe margin. Designers must verify that elevated VBR does not cause premature clamping in high-ambient environments, especially near heat-generating components.