STMicroelectronics STP40N20

Overview

STP40N20 from STMicroelectronics is an N-channel 200V power MOSFET in TO-220 package, rated for 40A continuous drain current at 25°C, with R_DS(on) ≤ 0.045Ω at V_GS = 10V and total gate charge Q_g = 75nC. It features low intrinsic capacitances (C_iss = 2500pF), 100% avalanche tested, and is optimized as a primary switch in isolated DC-DC converters.

For engineers reviewing the STP40N20 datasheet, STP40N20 pinout, STP40N20 application, or STP40N20 equivalent, key selection criteria include its 200V V_DS, 40A I_D rating, 0.045Ω on-resistance, 75nC gate charge, and TO-220 thermal resistance (R_thj-case = 0.78°C/W) - all critical for high-efficiency switching power supply design.

Technical Context

This STripFET™ MOSFET employs a planar vertical structure optimized to minimize gate charge and input capacitance, enabling fast switching with reduced drive loss. Its low C_iss/C_oss ratio (2500pF/510pF) supports stable operation under hard-switching conditions in flyback and forward converters.

The device integrates a robust body diode with t_rr = 192ns and Q_rr = 922nC at 25°C, supporting synchronous rectification and snubberless operation in resonant topologies. Avalanche ruggedness (E_AS = 230mJ) ensures reliability during unclamped inductive switching events.

Key Specifications

Pinout & Package

STP40N20 uses a standard TO-220 package with three leads: Gate (pin 1), Drain (pin 2), Source (pin 3). The metal tab is electrically connected to the Drain terminal and serves as the primary heat dissipation path. Mounting requires insulating hardware when heatsink is grounded.

Key Features

Applications

Equivalent & Alternatives

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

Compared with IRFP460 and IXTH40N20, STP40N20 delivers superior high-frequency efficiency via lower Q_g and C_iss, while its 230mJ E_AS provides verified ruggedness absent in the IXTH40N20 and significantly exceeding IRFP460's typical 110mJ rating - critical for industrial power supply longevity.

Availability

STP40N20 is available at Aetrix Electronics and suitable for server power supplies, industrial AC-DC adapters, and solar microinverters requiring stable component supply and long-term industrial lifecycle support.

Supply support for STP40N20 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.

The STripFET™ power MOSFET product line targets high-efficiency switched-mode power conversion, emphasizing low gate charge, rugged avalanche performance, and thermal reliability in TO-220 and surface-mount packages.

FAQ

What is the maximum safe operating temperature for STP40N20 junction?

The maximum operating junction temperature (T_j) is 150°C, as specified in the Absolute Maximum Ratings table. Continuous operation above this limit risks permanent degradation of R_DS(on) and gate oxide integrity. Thermal design must ensure T_j remains ≤150°C under worst-case ambient and power dissipation conditions, using the R_thj-case = 0.78°C/W value for TO-220 mounting.

Can STP40N20 be used in a synchronous rectifier configuration?

Yes - STP40N20's low R_DS(on) (≤0.045Ω) and fast body diode (t_rr = 192ns) make it suitable for secondary-side synchronous rectification in LLC and flyback converters up to 300kHz. However, external gate timing control is required to avoid shoot-through; it does not integrate adaptive dead-time control or integrated drivers.

Is STP40N20 lead-free and RoHS compliant?

Yes - STP40N20 is manufactured in an ECOPACK® package with lead-free second-level interconnect, fully compliant with RoHS Directive 2011/65/EU and JEDEC Standard JESD97. The inner box label confirms the lead-free category, and soldering profiles follow IPC/JEDEC J-STD-020 for lead-free reflow.

Does STP40N20 require a gate resistor for stability?

Yes - a gate resistor (typically 4.7Ω to 22Ω) is required to dampen ringing caused by PCB trace inductance interacting with C_iss and gate driver output impedance. The datasheet's switching time test circuit (Figure 16) specifies R_G = 4.7Ω, and omitting it risks oscillation, increased EMI, and accelerated gate oxide wear.