STMicroelectronics STW40N20

Overview

STW40N20 from STMicroelectronics is an N-channel 200V, 40A, 0.038Ω R_DS(on) Power MOSFET in TO-247 package, optimized for high-efficiency isolated DC-DC converters as a primary switch. It features low gate charge (75 nC), low output capacitance (510 pF), and 100% avalanche tested ruggedness with 230 mJ single-pulse energy rating.

For engineers reviewing the STW40N20 datasheet, STW40N20 pinout, STW40N20 application, or STW40N20 equivalent, key selection criteria include thermal resistance (R_thj-case = 0.78°C/W), safe operating area at high dv/dt (12 V/ns), and gate-drive compatibility with standard 10V logic-level controllers in hard-switched topologies.

Technical Context

This STripFET™ II MOSFET uses a planar vertical structure with minimized intrinsic capacitances to reduce switching losses and improve efficiency in high-frequency power conversion. Its low C_iss/C_oss ratio (2500 pF / 510 pF) supports ZVS-capable resonant designs while maintaining robust dv/dt immunity.

The device integrates a fast-recovery body diode (t_rr = 192 ns @ T_j = 25°C) with low Q_rr (922 nC), enabling reliable synchronous rectification and freewheeling operation in LLC and phase-shifted full-bridge converters without external Schottky supplementation.

Key Specifications

Pinout & Package

STW40N20 is housed in a TO-247 package with three leads: Gate (pin 1), Drain (pin 2), Source (pin 3). The metal tab is electrically connected to the Drain terminal and must be isolated from heatsink unless referenced to high-side potential.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar N-channel 200V power MOSFET applications.

Compared with IXTH40N20 and IRFP460, STW40N20 delivers superior figure-of-merit (R_DS(on) × Q_g = 2.85 Ω·nC), verified avalanche ruggedness, and lower thermal resistance-making it optimal for high-density, high-reliability 200V power stages where efficiency and robustness are co-prioritized.

Availability

STW40N20 is available at Aetrix Electronics and suitable for server power supplies, industrial AC-DC adapters, and telecom rectifier modules requiring stable component supply and long-term production continuity.

Supply support for STW40N20 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, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

STW40N20 belongs to the STripFET™ II family, engineered specifically for high-frequency, high-efficiency power conversion in isolated DC-DC topologies where low gate charge and rugged avalanche performance are essential.

FAQ

Is STW40N20 suitable for gate-driving with 5V logic?

No. STW40N20 has a gate threshold voltage (V_GS(th)) of 2–4 V and requires 10 V for full enhancement to achieve its specified 0.038 Ω R_DS(on). Driving with only 5 V results in partial turn-on, excessive conduction loss (>0.2 Ω), and thermal runaway risk at rated current. A dedicated 10–15 V gate driver is mandatory.

What is the maximum continuous drain current at 100°C case temperature?

The maximum continuous drain current (I_D) at T_C = 100°C is 25 A, as specified in Table 1 of the datasheet. This reflects thermal derating due to reduced channel mobility and increased R_DS(on); operation above this current requires active cooling or pulse-width limitation to maintain junction temperature below 150°C.

Does STW40N20 have a built-in ESD protection diode on the gate?

No. STW40N20 lacks integrated gate ESD protection. Its gate oxide is rated for ±20 V absolute maximum V_GS, and exposure to static discharge exceeding ±1000 V HBM can cause irreversible damage. External gate protection (e.g., 12 V Zener clamp between gate and source) is required during PCB handling and assembly.

Can STW40N20 replace STP40N20 in existing TO-220 layouts?

No. STW40N20 uses TO-247 packaging with different lead spacing (E = 10.0–10.4 mm), tab orientation, and thermal mounting requirements versus TO-220 (E = 15.45–15.75 mm). Mechanical interference, solder joint stress, and thermal interface mismatch make direct replacement non-viable without PCB redesign and thermal validation.