STMicroelectronics STTH50W03CW

Overview

STTH50W03CW from STMicroelectronics is a dual-die ultrafast high-voltage rectifier diode in TO-247 package, rated for 300 V repetitive peak reverse voltage, 2 × 25 A average forward current (per diode), and 20 ns typical reverse recovery time. It employs Turbo 2 silicon technology and is engineered for secondary-side rectification in high-power DC/DC and DC/AC converters used in MIG/MMA/TIG welding machines.

For engineers reviewing the STTH50W03CW datasheet, STTH50W03CW pinout, STTH50W03CW application, or STTH50W03CW equivalent, key selection criteria include reverse recovery performance at 125 °C, thermal resistance (1.8 °C/W per diode), softness factor (0.3), conduction loss modeling (P = 0.9×IF(AV) + 0.012×IF²(RMS)), and TO-247 mechanical mounting requirements (0.5 N·m recommended torque).

Technical Context

The STTH50W03CW integrates two independent ultrafast rectifier dies in a single TO-247 package with common cathode (K) and isolated anodes (A1, A2), enabling synchronous or interleaved operation in high-frequency bridge configurations. Its Turbo 2 process delivers low QRR (170 nC typ.), low IRM (7–9 A typ. at 125 °C), and stable VF across temperature (1.0–1.5 V at 25–150 °C, 25 A).

Thermal design relies on junction-to-case conduction (Rth(j-c) = 1.8 °C/W per diode, total Rth(c) coupling = 0.2 °C/W), supporting continuous operation up to Tj = 175 °C. Dynamic behavior is characterized under controlled dIF/dt conditions (–200 A/µs), with trr tightly specified at 20–27 ns and tfr = 120 ns.

Key Specifications

Pinout & Package

Housed in ST's standard TO-247 package (4.46 g, epoxy UL94 V0 compliant), the STTH50W03CW features three terminals: Cathode (K), Anode 1 (A1), and Anode 2 (A2). The device uses a common-cathode dual-die configuration, allowing independent control of each rectifier path while sharing thermal mass and mounting interface.

Key Features

Applications

Availability

STTH50W03CW is available at Aetrix Electronics and suitable for MIG/MMA/TIG welding equipment, industrial DC/DC converters, and uninterruptible power systems requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for STTH50W03CW 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 analog, digital, and mixed-signal ICs, discrete devices, and MEMS sensors for industrial, automotive, and power applications.

The STTH50W03CW belongs to ST's Turbo 2 ultrafast rectifier product line, developed specifically for high-efficiency, high-reliability secondary-side rectification in demanding industrial power conversion systems.

FAQ

What is the thermal coupling between the two diodes inside the STTH50W03CW?

The STTH50W03CW exhibits 0.2 °C/W thermal coupling resistance (Rth(c)) between its dual dies, meaning heat generated in one diode raises the junction temperature of the other by 0.2 °C per watt dissipated. This coupling is accounted for in the total thermal model: Tj(diode 1) = P₁×1.8 + P₂×0.2. Designers must include this cross-heating effect when calculating worst-case junction temperatures under unbalanced loading.

Can STTH50W03CW replace STTH30L06D in a 300 V welder design?

No - STTH30L06D is a 600 V, 30 A single-die device with slower recovery (trr ≈ 50 ns) and higher VF (1.7 V typ. at 25 A). STTH50W03CW offers lower VRRM (300 V), higher current (2 × 25 A), faster trr (20 ns), and softer recovery (Sfactor = 0.3 vs ~0.1), making it unsuitable as a drop-in replacement unless the DC bus voltage is reduced to ≤250 V and layout accommodates dual-anode routing.

How is the 50 A "per device" rating achieved in practice?

The 50 A "per device" rating reflects the sum of both diodes' IF(AV) ratings (25 A each) under balanced conduction and Tc = 100 °C. It requires symmetrical PCB copper pour, equal trace inductance to A1/A2, and shared heatsink contact. Uneven current sharing due to layout asymmetry or thermal gradients reduces usable current; ST recommends using external balancing resistors or current-sharing inductors for full 50 A utilization.

Is the TO-247 mounting torque specification mandatory for thermal performance?

Yes - ST specifies 0.5 N·m recommended torque (max 1.0 N·m) to ensure optimal thermal interface between the TO-247 flange and heatsink. Under-torquing increases thermal resistance beyond 1.8 °C/W; over-torquing risks package cracking or die shear. Use calibrated torque screwdrivers and thermal interface material (e.g., phase-change pad or silicone grease) to achieve consistent Rth(j-c) performance across production units.